Retrospective study of
i mmuni zat i on
rates of rural area
k indergarten
students / Darlene H.
Scavona.
Thesis Nurs. 1999 S288r
RETROSPECTIVE STUDY OF IMMUNIZATION RATES OF RURAL AREA
KINDERGARTEN STUDENTS

by
Darlene H. Scavona

Submitted in partial Fulfillment of the Requirements for the
Master of Science in Nursing Degree

Edinboro University of Pennsylvania

Approved by:

Judi*
Con

Schilling, PhD, CRNP
itte^Chairperson

Jan<

Sjsel, kN, PhD
Tftee Member

Date

/m

mm/—
fa-'G—_____

Nancy Rea, MHSA
Committee Member
Erie County Department of Health

Date

ii

Abstract
Retrospective Study of Immunization Rates of Rural Area Kindergarten Students

National efforts have been directed toward the reduction of vaccinepreventable diseases through improved immunization rates. The purpose of this study
was to determine the immunization status of a rural childhood population. Percent of

children with up-to-date immunization series and individual antigens was calculated
at the ages of 12 and 24 months, and school entry. Percent of children with age-

appropriate immunization series was calculated at the ages of 3, 5, 7, 16, and 19
months, and school entry. Data were compiled using school-based Certification of

Immunization Records of 122 kindergarten students in a rural school district in

northwestern Pennsylvania.

Seventy-five percent of the students had an up-to-date immunization series by
the age of 24 months; rates increased to 86% by age of school entry. Rates of age-

appropriate immunization series were lower. Rates of individual antigen levels were
slightly higher than rates for up-to-date immunization series at 24 months. At age of
school entry, coverage rate of the antigens DTP5, MMR2, or HBV3 was from 86% to
93%.

Less than 90% of this rural kindergarten population was fully immunized.

Dependent care agencies of the community were inadequate to meet the children’s
therapeutic self-care demand. Follow-up studies are needed to determine if low

immunization rates continue, and to identify existing barriers to immunization of the

community, primary care providers and/or health care system, and parents.

iii

Acknowledgments
I would like to acknowledge all those persons that have made this thesis
possible. My sincere gratitude is extended to the members of my committee: Dr.

Judith Schilling, Dr. Janet Geisel, and Mrs. Nancy Rea for their commitment,
direction, and time. I would like to thank the superintendent and school principal of

the rural school district for allowing me to conduct this research in their elementary

school. Finally, a special recognition goes to my husband Jim, and my children Joe
and Alicia for their patience and support throughout this thesis.

iv

Table of Contents

Contents

Page

List of Tables

Vll

Chapter I. Introduction

1

Background of the Problem

1

Theoretical Framework

4

Statement of the Problem

6

Statement of the Purpose

6

Definitions of Terms

6

Assumptions

7

Limitations

8

Summary

8

Chapter II. Review of Literature
National Immunization Survey

10

10

National immunization rates

11

Pennsylvania immunization rates

14

Erie County Immunization Rates

17

Rural versus Urban Population Immunization Rates

17

School-based Immunization Survey

19

Summary

20

Chapter III. Research Methodology

Research Questions

.22
.22

V

Operational Definitions

,22

Research Design

23

Sample,

27

Research Consent

,27

Data Collection

,27

Pilot Study

28

Data Analysis

29

Summary

29

Chapter IV. Results

31

Sample Group

31

Immunization Data,

31

Up-to-Date Immunization Coverage Rates

32

Properly Spaced Doses

34

Age-Appropriate Immunization Coverage Rates

34

Individual Antigen Coverage Rates

37

Pennsylvania’s Mandated Immunizations for School Entrance

39

Summary

39

Chapter V. Discussion

.41

Conclusions

,43

Recommendations

,47

References

,49

vi

Appendix

A. Certification of Immunization Record

53
54

vii

List of Tables
Table

Page

1. Single Antigen Coverage Rates - United States, 1994-1997

12

2. Immunization Series Coverage Rates - United States, 1994-1997

13

3. Immunization Series Coverage Rates - Pennsylvania, 1994-1997

15

4. Individual Antigen Coverage Rates - Pennsylvania, 1996-1997

16

5. Up-to-Date Immunization Series Coverage Rates

24

6. Ages-Appropriate Immunization Series by Age

25

7. Proper Spacing between Doses of Vaccines

26

8. Coverage Rates of Up-to-Date Immunization Series by Respective Ages

33

9. Coverage Rates of Age-Appropriate Immunization Series by Respective Ages...36

10. Coverage Rates of Individual Antigens by Age

38

1

Chapter I
Introduction
This chapter provides an overview of the importance of immunizations for the

prevention of infectious diseases and the problem of inadequate immunization
coverage of children in the United States. Dorothea Orem’s (1995) Self-Care Deficit
Theory serves as the framework for this research and is discussed. Statements of the

research problem and purpose define the focus of this study. Definitions of terms,
limitations, and assumptions of this study are also provided.

Background of the Problem
The reduction and eradication of infectious diseases are among the most

important public health accomplishments in the past 100 years (United States
Department of Health and Human Services [US DHHS], 1991). These

accomplishments are the result of a combination of factors: improved sanitation,
water treatment, basic hygiene, and the discovery of antimicrobial drugs. However,
the most striking single factor is the development and use of vaccines that provide a

safe and effective way to prevent infectious diseases.

Use of vaccines played a major part in the global eradication of small pox in

1977 and the significant reduction of diphtheria and poliomyelitis cases. Between
1988 and 1998 only two to five cases per year of diphtheria were reported in the

United States (Centers for Disease Control and Prevention [CDC], 1994b; CDC,
1997c- CDC, 1998d). Since 1979 there have been no reported cases of poliomyelitis

caused by wild-type virus in the United States (CDC, 1997c). National eradication of

2

diphtheria and poliovirus is possible if immunizations are up-to-date for all children,

adolescents, and adults.
Progress toward the reduction and eradication of many infectious diseases is

impressive, but should not be taken for granted. Infectious diseases remain a public
concern as a cause of illness with potential serious sequela, and even death (CDC,
1989, CDC, 1991; CDC, 1994c; CDC, 1998a; CDC, 1998e). As the result of
nonimmunization or underimmunization, small epidemics of infectious diseases do

occur, as evidenced by the resurgence of measles in 1989 (CDC, 1998a). Between
1984 and 1988 the incidence of measles was reduced to less than 4,000 cases
annually. Alarmingly, between 1989 and 1991, the incidence of measles rose sharply

to greater than 55,000 cases resulting in more than 120 measles related deaths (CDC,

1998a). As is true of other vaccine-preventable diseases, the resurgence of measles
was due to inadequate immunization of susceptible individuals.

Another major health concern of the nation is the rising incidence of acute

hepatitis B viral infections.(CDC, 1991). It is an infectious disease of adolescents and

adults incidental to drug use, sexual contact, or occupational or household exposure.
During the 1980s, the incidence of acute hepatitis B infections increased by 37%.
Each year between 1980 and 1991 there were approximately 250,000 to 300,000 new

cases of acute hepatitis B infections. Four thousand to 5,000 persons who were
chronically infected with hepatitis B virus died each year as a result of liver

complications secondary to the hepatitis B infection. .

3

Proposed national strategies to improve the overall health of Americans have
been published m a document entitled Healthy People 2000: National Health

Promotion and Disease Prevention Objectives (Healthy People 2000) (US DHHS,
1991). Of the numerous strategies addressed in this national document, the

prevention and reduction of infectious diseases ranked among the nation’s top three
priorities. National objectives are to reduce indigenous cases of vaccine-preventable

diseases (Healthy People 2000 objective 20.1) by increasing the immunization
coverage among preschoolers and adults. By the year 2000, the goals of Healthy

People 2000 are to have 90% of children at the age of 2 years, and 95% of children
enrolled in a licensed child care facility or school, receive a basic immunization series

(Healthy People 2000 objective 20.11). Since 1994, the Centers for Disease Control

and Prevention (CDC) have estimated coverage rates for two immunization series

(CDC, 1998b). The first of these series consists of four doses of diphtheria and
tetanus toxoids and pertussis vaccine (DTP), three doses of poliovirus vaccine (OPV),
and one dose of any measles-containing vaccine (MCV) (4:3:1 series). The second
series includes the vaccine doses of the 4:3:1 series and an additional three doses of

Haemophilus influenzae type b vaccine (HIB) (4:j:1:3 series).

In 1989, the baseline estimates by the CDC reported that 70% to 80% of

preschool children were immunized, but that in pockets of some high-risk groups less
than 50% of preschool children were immunized (US DHHS, 1991). Currently

estimates of immunization rates remain low, particularly in high-risk groups (CDC,

1997b* CDC 1998c; Lowery et al., 1998). In 1997, the CDC’s National

4

Immunization Survey reported that only 78% of preschoolers were adequately
immunized (CDC, 1998c) and immunization rates for high-risk preschool populations

were substantially lower (CDC, 1997d). Children at high-risk for underimmunization
were members of both urban and rural populations (Lowery et al., 1998). Generally

they were from poor families, with less educated parents, and of racial minorities.

However, unlike the children living in urban areas, the children living in rural areas
had fewer available health care providers, and a greater number of their families
lacked health care insurance (Lowery et al., 1998).

Healthy People 2000 recommendations to improve immunization coverage
suggested broadening the immunization laws for schools, preschools, and day care

settings (Healthy People 2000 objective 20.13) (US DHHS, 1991). Secondly,
primary care providers are to counsel and inform consumers about immunizations and

administer vaccinations in a timely manner (Healthy People 2000 objective 20.14).
Thirdly, immunizations are not to be cost prohibitive for any American (Healthy

People 2000 objective 20.15). Finally, a method of retrieving immunization

information was needed to evaluate the progress towards achieving the immunization

goals of Healthy People 2000 was (Healthy People 2000 objective 22.3).
Theoretical Framework
This research was based on Dorothea Orem’s Self-Care Deficit Theory

(1995). Self-care is the "practice of activities that individuals initiate and perform on

their own behalf in maintaining life, health, and well-being" (Orem, 1995, p. 104).
Self-care requisite is a term used to specify a need for self-care. A person’s acquired

5

ability or power to perform self-care is known as

self-care agency. When a person

acts on behalf of another individual, such as a parent or nurse caring for a child or
patient, their ability to perform care is known as dependent care agency or nursing

agency. Actions performed by another person for a dependent child or person is

referred to as dependent self-care.

Therapeutic self-care demand is the summation of all the actions to be taken
in the process of meeting one’s existent self-care requisites or need. In the case of a

child or person of limited self-care agency, a dependent care agency or nursing

agency is initiated to perform the actions of therapeutic self-care demand and fulfill
the requisites of self-care.

Both Healthy People 2000 (1991) and Orem (1995) identify prevention from

infectious diseases as necessary to preserve optimal health. Orem referred to disease
prevention as a universal self-care requisite. Its purpose is to protect the body's

integrity and functioning from the hazards of disease and its consequences. To date,
prevention from vaccine-preventable diseases is best achieved by up-to-date, age-

appropriate immunization practices as suggested by CDC (CDC, 1994a).
An estimated one million preschool children remain inadequately immunized

(Lowery et al., 1998). The fact that so many US children are underimmunized
indicates that our national self-care requisite to protect our nation's children has been
inadequately addressed.

As a primary care provider, particularly in rural areas, the nurse practitioner is

responsible to assure that all efforts are undertaken to deliver optimal preventive

6

health care including immunizations. Determinations of a community’s rates of
immunization help to identify health care trends in a community and its immunization

practices. Retrospective studies of immunization rates of school age children fulfill
this need.
Statement of the Problem
Estimated national immunization levels of preschool children are suboptimal
(US DHHS, 1991). Only 70% to 80% of U.S. preschool children are adequately
immunized and in some high-risk populations less than 50% of the children are

immunized.
Much of research has focused on the underimmunized populations in urban

areas; limited research has focused on the childhood populations in rural areas.
(Lowery et al., 1998). Similar to their urban counterparts, rural population groups are

often poor, less educated, and lack health insurance.
Statement of the Purpose
The purpose of this research was to identify the immunization status of a rural

childhood population. This study determined the immunization coverage rates of
rural kindergarten students in northwestern Pennsylvania.

Definition of Terms
The following terms are defined as they were used in this study:

1

Age-appropriate immunizations are immunizations administered to

children at the ages recommended.

7

2. Immunization is the process of inducing immunity by administering an

antigen (CDC, 1994a).
3. Up-to-date immunizations are the immunizations recommended by the

America Academy of Pediatrics or the Centers for Disease Control and Prevention

that should be administered to a child by the particular age being evaluated (Zell,
Dietz, Stevenson, Cochi, & Bruce, 1994).

4. Vaccination is the physical act of administering any vaccine or toxoid
(CDC, 1996).
Assumptions
This research was based on the following assumptions:
1. The process of immunity against vaccine-preventable diseases is most

effective when immunizations are administered according to the Recommended
Immunization Schedule of the Centers for Disease Control and Prevention and/or the
American Academy of Pediatrics (American Academy of Pediatrics [AAP], 1991;

CDC, 1994a).
2. Underimmunized children must be identified to improve the immunization
coverage rates.

3. All children are entitled to equal protection from vaccine-preventable
diseases through the process of immunization.
4. Immunization data provided by the parents, guardians, or health care

providers are accurate.

8

5. All data were correctly entered onto the students’ Certificate of

Immunization Records.
6. There were no contraindications that would prevent any student from

being immunized by the age of school entry.

Limitations
Limitations to this research were:

1. This research was limited to a convenience sample of kindergarten
students in a small rural school district located in northwestern Pennsylvania.

2. This study included only children bom between September 1, 1992 and
August 31, 1993.
3. Immunization coverage rates were limited to immunizations mandated by

the Commonwealth of Pennsylvania for first time entry into school for the school
year 1998/1999. These immunizations included DTP, poliovirus, MMR, and hepatitis

B (Pennsylvania Department of Health, 1983/1997).
4. Findings of this retrospective study were of past events and did not reflect
the immunization status of current 2-year old children.

Summary
It is possible to eradicate or reduce vaccine-preventable diseases by
widespread, appropriate immunization practices (CDC, 1994a). Unfortunately, only

70% to 80% of our nation’s preschoolers were adequately immunized and among
some high-risk populations less than 50% of preschoolers were immunized (US

DHHS, 1991).

9

Similar to urban areas, rural areas may have pockets of underimmunized

preschoolers, but little research has focused on this population group. For this reason,
the purpose of this retrospective study was to determine the immunization status of a

rural kindergarten population. As a retrospective study, it identified past
immunization practices that would indicate the need for further study of the
community’s health care delivery system, health care providers, and client/cultural

needs.
Orem’s Self-Care Deficit Theory (1995) served as the theoretical basis for this

research and was discussed. In addition, definitions of terms, assumptions, and

limitations were enumerated in this chapter.

10

Chapter II
Review of Literature
The purpose of this study was to identify the immunization status of a rural

childhood population in northwestern Pennsylvania. To understand immunization

past and current trends, this review of literature examines immunization assessments

made on a national, state (Pennsylvania), and county (Erie) levels. Additional
literature reviewed includes studies that examine the immunization status of rural

childhood populations and studies that use school-based immunization records to
assess immunization status.

National Immunization Survey

In April of 1994, the CDC’s Childhood Immunization Initiative implemented
the National Immunization Survey to monitor the occurrence of vaccine-preventable
diseases and to determine the immunization status of preschoolers (CDC, 1995). This

national survey continues to provide data regarding the nation, each state, and
selected high-risk urban areas. Annual estimations of vaccination coverage rates

among children aged 19 to 35 months are computed to assess what progress was

made towards the attainment of targeted goals set forth by the Childhood
Immunization Initiative. By 1996, the CDC’s goals were to immunize 90% of
children age 24 months against diphtheria, tetanus, pertussis, poliovirus, measles,

mumps and rubella; and immunize 70 % of children age 24 months against hepatitis

B virus. In 1998, the goal for hepatitis B vaccine (HBV) coverage was increased to

90% or better (CDC, 1997b).

11

The scope of the National Immunization Survey is limited (CDC, 1998b). It
does not take into account the dates of each vaccination, the age-appropriateness of
the vaccinations, or whether vaccine doses were properly spaced. Surveyed sites are

limited to metropolitan areas with high-risk urban populations. Areas with rural
populations are not studied.

National immunization rates. Between 1994 and 1997, national immunization
rates reached targeted goals of 90% coverage for four of five single antigens for a
sample group of children with a median age of 27 months (Table 1) (CDC, 1998b).

Rates ofcoverage with HBV surpassed 1996 targeted goals for 70% coverage, having

increased from 37% in 1994 to 82% in 1996. But in 1997, with 84% coverage, HBV

did not yet reach the increased goal of 90% for 1998 (CDC, 1997b).
Preschool children are best protected from selected vaccine-preventable
diseases when they receive a full series of immunizations (CDC, 1994a). The CDC

estimates the coverage rates for two immunization series (CDC, 1998b). The first of
these series consists of four doses of diphtheria, and tetanus toxoid, and pertussis

vaccine (DTP), three doses of poliovirus (OPV/IPV), and one dose of measles­
containing vaccine (MCV) (DTP4:OPV3:MCV1). The second immunization series
includes three doses of Haemophilus influenzae type b vaccines (HIB) in addition to
the doses of DTP, OPV, and MCV (DTP4:OPV3:MCV1:HIB3). In 1997, national

rates for a sample group of children with a median age of 27 months was 78% for the

12

Table 1

Single Antigen Coverage Rates - United States, 1994-1997

Percent Covered (*CI)

Vaccine /Series

1994

1995

1996

lDTP/DT
> 3 DTP/DT

94 + 0.6

95 + 0.6

95 + 0.4

95 + 0.4

> 4 DTP/DT

76+1.1

79+1.0

81 + 0.7

81+0.7

83 + 1.0

88 + 0.8

91+0.5

91+0.5

1 doses

89 + 0.8

90 + 0.7

91+0.5

91+0.5

3HBV > 3 doses

37+1.2

68+1.0

82 + 0.7

84 + 0.6

Poliovirus

2MCV

3 doses

1997

Notes. Data taken from the annual National Immunization Survey (Centers for
Disease Control and Prevention, 1998b). In 1994 data collected from April through
December. From 1995 to 1997 data collected from January through December.

Sample groups had median age of 27 months.
1 DTP/DT = diphtheria and tetanus toxoids, and pertussis vaccine/diphtheria and

tetanus toxoids. 2 MCV = any measles-containing vaccine.3 HBV - hepatitis B
vaccine.

*CI = Percents computed at 95% confidence interval.

13

DTP4:OPV3:MCV1 series and 76% for DTP4:OPV3:MVC1:HIB3 (Table 2) (CDC,

1998b). It was suggested that the reason why the basic series rates were lower was

because the fourth dose of DPT is gi ven after the first year of life (CDC, 1998b). It

was thought that this might be an age that is more difficult to get children to return to
their health care provider.

Table 2
Immunization Series Coverage Rates - United States, 1994-1997

Percent Covered (*CI)
Vaccine /Series

1994

1995

1996

1997

a4:3:l

74+ 1.1

76+ 1.0

78 + 0.8

78 + 0.7

b4:3:l:3

69+ 1.2

74+ 1.0

77+ 0.8

76+ 0.8

Notes. Data taken from the National Immunization Survey (CDC, 1998b). In 1994

data collected April through December. From 1995 to 1997 data collected January
through December. Median age of sample group was 27 months.

a4:3:l

4 doses of diphtheria and tetanus toxoids, and pertussis vaccine/ diphtheria

and tetanus toxoid; 3 doses of poliovirus; and 1 dose of measles-containing vaccine.

b4:3:1:3 = 4 doses of diphtheria and tetanus toxoids, and pertussis vaccine; 3 doses of
poliovirus vaccine; 1 dose of measles-containing vaccine; and 3 doses of
Haemophilus influenzae type b vaccine.

*CI = percents computed at 95% confidence interval.

14

Pennsylvmiaummunization^^ Compared to national rates, Pennsylvania’s
rates ofcoverage were higher for the two basic immunization series; but remained

below the 90/o goal of the CDC’s Childhood Immunization Initiative (CDC, 1998b).
In 1997, Pennsylvania’s immunization rates for the basic immunization series of

DTP4:OPV3:MCV1 and DTP4:OPV3:MCV1:HIB3 reached only 82% and 80%,
respectively (Table 3).

Pennsylvania s coverage rates for individual antigens were higher than the

rates for immunization series. In 1996 and 1997, the Pennsylvania rates of coverage
were at least 90% or better for three doses of DTP, three dose of OPV, and one dose
of MCV (Table 4). Coverage rates in 1997 were 83% for HBV, and 84% for the
fourth dose of DTP, both below 90% goals. During the same year, coverage rates

dropped for poliovirus from 94% in 1996 to 90% in 1997.

Pennsylvania’s immunization coverage rates during 1997 were not impacted
by changes in the Commonwealth’s immunization requirements for school entrance

(Pennsylvania Department of Health, 1983/1997 #173). Stricter immunization
requirements beginning in the school year of 1997/98 mandated that children entering
school for the first time must have a dose of DTP on or after the 4th birthday, a second

dose of MMR, and three doses of hepatitis B vaccines. Research suggested that

immunization compliance could be promoted by state mandated physical
examinations prior to school entry and by increasing school immunization

requirements (Bradford, Benedum, Heald, & Petrie, 1996). Expectations were that if

15

Table 3

Immunization Series Coverage Rates - Pennsylvania, 1994-1997

Percent Covered (*CI)

Vaccine /Series

a4:3:l
b4:3:l:3

1994

1995

1996

1997

77+ 5.1

78 + 4.5

81 + 3.6

82+ 3.6

NA

78 + 4.7

79+ 3.7

80+ 3.7

Notes. Data taken from the annual National Immunization Survey (Centers for
Disease Control and Prevention [CDC}, 1995; CDC, 1997a; CDC, 1997b; CDC,

1998b). In 1994 data collected from April through December. From 1995 to 1997

data collected January through December. NA denotes that datum was not available.

a4:3:l

4 doses of diphtheria and tetanus toxoids, and pertussis vaccine/diphtheria

and tetanus toxoid; 3 doses of poliovirus; and 1 dose of measles-containing vaccine.

b4:3:l:3 = 4 doses of diphtheria and tetanus toxoids, and pertussis vaccine; 3 doses of
poliovirus vaccine; 1 dose of measles-containing vaccine; and 3 doses of

Haemophilus influenzae type b vaccine.

*CI = Percents computed at 95% confidence interval.

16

Table 4
Individual AntigenCoverageRates, - Pennsylvania, 1996-1997

Percent of Covered (*CI)
Vaccine/Dose

1996

1997

3 doses DTP/DT

96+ 1.8

96+ 1.9

> 4 doses DTP/DT

83+ 3.5

84+ 3.5

Poliovirus > 3 doses

94 + 2.2

90 + 2.9

2mcv

1 doses

92+ 2.6

91 + 0.5

3HBV

3 doses

84+ 3.3

83+ 3.3

'dtp/dt

Notes. Data taken from the National Immunization Survey (Centers for Disease
Control and Prevention [CDC], 1997b; CDC, 1998b). In 1996 and 1997 data was

collected January through December.
1 DTP/DT = Diphtheria, tetanus toxoids and pertussis vaccine/diphtheria and tetanus

toxoids. 2 MCV = any measles-containing vaccine. 3 HBV = Hepatitis B vaccine.
*CI

Percents computed at 95% confidence interval.

17
additional immunizations were required for school entrance, parents and health care

providers would be more likely to obtain the proper immunizations.
Erie County Immunization Rates

According to N. Rea (personal communication, April 1, 1999) the Health Cost
Summit is currently in the process of conducting an audit to determine the

immunization status of children age 12 to 23 months bom in Erie County. Data for
this audit was collected using the health records of private and public health care

providers throughout the County. Preliminary results as of February 1,1999,
indicated that 86.9% of children at 12 months of age were up-to-date for three doses
of DTP, two doses of OPV, and three doses of HIB.

These findings are similar to the coverage rates of children seen at public

health clinics of the Erie County Health Department (Erie County Department of

Health, 1999). As of March 1, 1999, an estimated 84% of children less than 24
months of age seen by the clinics had up-to-date immunizations.

Rural versus Urban Populations Immunization Rates
Within the past 10 years immunization baseline data were collected in

numerous urban settings, but similar baseline data in rural settings were limited
(Lowery et al., 1998). Lowery et al. completed an extensive comparative analysis of

populations in both rural (nonmetropolitan area) and urban areas. This research was
based on two national studies, the 1991 National Maternal and Infant Health Survey

(NMIHS) and the 1993 National Health Interview Survey (NHIS), with a total sample
group of 1432 rural children an
18

1991 and 1993, approximately 34% to 37% of children in rural and urban areas were
inadequately immunized. Similarities of underimmunized rural and urban childhood

populations indicated that they were both more likely to be of a racial minorities,
from families with low incomes, and had parents who were less educated.
Undenmmumzation did not necessarily correlate with either rural or urban place of

residence. Lowery cautioned that because two population groups shared similar
demographic characteristics it did not follow that similar solutions are applicable for

both populations. Solutions to the problem of underimmunization in a rural
population should be considered only within the context of the rural culture.

In 1990, a second study compared two Pennsylvania school districts (Bradford

et al., 1996). One school district was located in an urban community just outside of
Pittsburgh; the other was situated in a rural, outlying area. Immunization status was

computed in two stages: a review of school immunization records and follow-up
telephone survey to students’ parents. A total of 281 immunization records were
reviewed; 169 records were from the rural school district. All 281 students met the

Pennsylvania requirements for school entrance that mandated they have three doses

of DTP, three doses of OPV, and one dose ofMMR.
Telephone surveys to 237 students’ parents identified demographic data,

vaccination status, and barriers to immunizations (Bradford et al., 1996).

Demographic data revealed that both surveyed groups, rural and urban, consisted of
populations of a majority Caucasian race, higher income families, and coverage with

some form of health insurance.

No statistically significant correlation of students’

19

immunization status and their demographic data could be made. Reported
Vaccination status of this subset of students indicated that only 46% were fully

immunized with five doses of DTP, four doses of OPV, one dose of MMR, and one

dose of HIB. Most often the students were missing boosters, particularly the fifth

dose of DTP (24%) and HIB (23%), that were not required for school entrance.
Boosters were missing in spite of the fact that 96% of the underimmunized children
had seen a doctor within a year and 65% had seen a doctor within the past 6 months.

When parents were asked why their children were missing immunizations, 58% of
parents reported that they were unaware of the fact that their children were not fully

immunized .
School-based Immunization Survey
Retrospective studies of immunization rates in school populations provided an

accessible and inexpensive measurement of trends occurring in a specific population
served by multiple providers (Rodewald et al., 1993). Utilizing school immunization

records served to identify the majority of students in a community without regard to
provider. Furthermore, it was possible to identify children who had no specific

primary care provider or who had changed providers.
A large retrospective survey used school records to determine immunization

rates of kindergarten and first grade students enrolled in the 1990/1991 and
1991/1992 school years (Zell et al., 1994). Surveyed groups were selected from 18

large urban sites, one small city, and one rural area. In all sites surveyed, children

were underimmunized.

Only 11% to 58% (median 44%) of these children at age 2

20

years had an up-to-date DTP4: OPV3: MMR1 immunization senes. By the age of
school entrance coverage rates for the same series increased to between 71% to 96%
(median 87%). Inadequate spacing between doses of vaccines further reduced up-to-

date senes rates by 1 to 8 percentage points. Age-appropriate immunization series

had lower coverage rates than up-to-date series. Five percent to 20% (median 12%)
had immunization series that were age-appropriate.

Not including the fourth DTP (DTP4), immunization rates for specific
antigens were higher than up-to-date immunization rates (Zell et al., 1994). Twelve
percent to 63% of 2 year-olds received DTP4 as compared to 63% to 89% of 2 year-

olds who received three doses of DTP. Other vaccinations had similarly low rates.
Fifty-four percent to 80% of 2-year olds had three doses of OPV, and 52% to 80%

had the first dose of MMR (Zell et al., 1994).
Summary
The purpose of this retrospective study was to determine the immunization
status of kindergarten students in a rural school district. In 1996 and 1997, the

National Immunization Survey of the CDC reported that 90% or more of children age

24 months were immunized with the antigens of DTP third dose, OPV third dose, and
MMR first dose (CDC, 1997b; CDC, 1998b). Of the same population group,

however, only 78% to 81% had received combined immunization senes that included
four doses of DTP, three doses of OPV, and one dose of MMR in 1996 and 1997.
According to finding of one study, one-third of both rural and urban

populations were not fully immunized (Lowery et al., 1998) Rural and urban

21

populations at high risk for underimmunization were generally from families of lower
incomes, less educated, and of minority races.

A second study found that in rural and urban populations with a majority

Caucasian race, higher incomes, more education, and covered by health insurance,
children were still underimmunized (Bradford et. al, 1996). Most often the parents

reported that they were unaware of needed immunizations.
Lastly, the Zell et al.(1994) retrospective school based research found that

only 11% to 58% of children 24 months of age had a basic immunization series of
four doses of DTP, three doses of OPV, and one dose of MMR. By the age of school

entry the students’ immunization coverage had increased to levels between 71% and
96% for the same immunization series.

22

Chapter III

Research Methodology
The purpose of this research was to determine the immunization status of rural

kindergarten students in a northwestern Pennsylvania school district. This chapter
describes the methodology. Research questions, operational definitions, research

design, sample, research consent, data collection, pilot study, and data analysis are
discussed.

Research Questions
What percentage of kindergarten students in a northwestern Pennsylvania

rural school district had an up-to-date immunization series? What percentage of
kindergarten students had an up-to-date immunization series with all doses of
vaccines properly spaced? What percentage of kindergarten students had age-

appropriate immunization series? Lastly, what percentage of kindergarten students

has received each individual antigen?
Operational Definitions
The operational definitions utilized in this research study were:

1. Immunizations are included the vaccinations required by the

Commonwealth of Pennsylvania for first time entry into school for the school year

1998/99 (Pennsylvania Department of Health, 1983/1997). Pennsylvania school
immunization laws mandate that all students entering kindergarten must have four or
more doses of DTP, with one dose administered on or after the 4th birthday; three
doses of OPV/IPV; two doses of a measles-containing vaccine (preferably the MMR);

23
one dose of rubella containing vaccine (preferably MMR), one dose of mumps
containing vaccine (preferably MMR), and three doses of HBV.

2. Up-to-date immunizations are the vaccines doses recommended by the
Centers of Disease Control and Prevention (CDC) or American Academy of

Pediatrics (AAP,) for a child by the age 12 months, 24 months, and at age of school
entry (Table 5)(AAP, 1991; CDC, 1989; CDC, 1991; CDC, 1994a)
3. Age-appropriate immunizations are the vaccines doses administered

within a period up to 30 days after the latest age recommended by the CDC or AAP
(Table 6) (AAP, 1991; CDC, 1989; CDC, 1991; CDC, 1994a).
4. Properly spaced doses are immunizations administered on or after the

minimum recommended age (Table 7) (CDC, 1994a). Subsequent doses of

immunizations are spaced so that the interval between doses is not less than that
recommended by the CDC.

5. Certificate of Immunization Record (Appendix A) is a standardized form
supplied by the Pennsylvania Department of Health to each school district for the

purpose of recording a student’s dates of immunization (Pennsylvania Department of
Health, 1983/1997).

Research Design
This retrospective descriptive study used the school-based Certificate of

Immunization Records to collect data. This study was designed to determine the
immunization coverage rates of kindergarten students in a rural school district in
northwestern Pennsylvania.

24

Table 5

Up-to-Date Immunization Series

Age in months

Up-to-Date Immunization Series

12

'DTP/DT 3:2OPV 2:3HBV 2

24

DTP/DT 4: OPV 3:4MMR 1: HBV 3

5School Entry

DTP/DT 5: OPV 3: MMR2:HBV3

Notes. Immunization series are based on recommendations of the American
Academy of Pediatric (AAP,) and/or the Centers for Disease Control and Prevention

(CDC) (AAP, 1991; CDC, 1989; CDC, 1994a). Immunization series include
immunizations required in Pennsylvania for a kindergarten enrolled in school for the
year 1998/1999 (Pennsylvania Department of Health, 1983/1997).

!DTP/DT

diphtheria and tetanus toxoids and pertussis vaccine/diphtheria and

tetanus toxoids. 2OPV = oral poliovirus vaccine. 3 HBV = hepatitis B vaccine.

4MMR = measles, mumps, and rubella. 5School Entry = students were at least 60
months of age and no more than 72 months of age on 9-1-98.

25

Table 6
Ages-Appropriate Immunization Series

Age in months

Age-Appropriate Immunizations

3

'DTP/DT 1:2OPV 1:3HBV 1

5

DTP/DT 2: OPV2: HBV 2

7

DTP/DT 3: OPV2: HBV 2

16

DTP/DT 3: OPV2: HBV2:4MMR1

19

DTP/DT 4: OPV 3: HBV 3: MMR 1

5School Entry

DTP/DT 5: OPV 3: HBV 3: MMR 2

Notes. Before 1993, the Centers for Disease Control and Prevention (CDC) and the

American Academy of Pediatrics (AAP) recommended different ages for
administering the fourth dose of DTP and third dose of OPV (AAP, 1991; CDC,

1989; CDC, 1991). The CDC recommended giving these vaccinations at 15 months

of age. AAP recommended giving these vaccinations between 15 to 18 months of
age. As of 1998 the CDC and AAP recommended giving a second dose of MMR at
the age of school entry (CDC, 1998a).

^TP/DT = diphtheria and tetanus toxoid and pertussis vaccine/diphtheria and tetanus
toxoid. 2OPV = oral poliovirus vaccine.

3HBV = hepatitis B vaccine. 4MMR =

measles, mumps, and rubella vaccine. 5 School Entry = students were at least 60
months of age and no more than 72 months of age on 9 1 98.

26

Table 7

Proper Spacing Between Doses of Vaccines

Minimum interval between doses

Minimum Age

Vaccine

For first dose

Dose 1 to 2

Dose 2 to 3

Dose 3 to 4

'dpt/dt

6 weeks

4 weeks

4 weeks

6 months

2OPV

6 weeks

6 weeks

6 weeks

6 weeks

3IPV

6 weeks

4 weeks

6 months

12 months

1 month

4mmr
5hbv

Birth

1 month

a2 months

Notes. Proper intervals between doses recommended by the Centers for Disease

Control and Prevention (CDC) (CDC, 1994a).
!DTP/DT

diphtheria and tetanus toxoid and pertussis vaccine/diphtheria and tetanus

toxoid. 2OPV = oral poliovirus vaccine. 3jpy = inactivated poliovirus vaccine.

4MMR = measles, mumps, and rubella vaccine. 5HBV = hepatitis B vaccine.

a2 months = a child must be at least 4 months or older.

27
Sample
For the purpose of this research, a convenience sample of 125 kindergarten

students was used. This was the total kindergarten population of a northwestern

Pennsylvania rural school district. Kindergarten students were 5 years (60 months) to
6 years (72 months) old and bom between September 1, 1992 and August 31.1993.
They were enrolled m a public elementary school for the school year 1998/1999.

Research Consent
The researcher received written consent from the school district’s

superintendent to conduct this research in the elementary school. Permission was
given to use the kindergarten students’ Certification of Immunization Records

(Appendix A) to obtain data: immunization dates, dates of births, genders, and zip

codes.
Data Collection

Data were collected using the Certificate of Immunization Records (Appendix

A). The Certificate of Immunization Record is a form supplied to each school by the
Pennsylvania Department of Health for the purpose of recording a student’s dates of

immunization (Pennsylvania Department of Health, 1983/1997). All Pennsylvania

schools are mandated to maintain an immunization record for each student. Records

are kept on the school premises and are maintained by the school nurse or designee.
Upon first entry into school, parents or guardians must produce proof of their

children’s immunizations. Children’s baby books or physician statements are used to
verify immunization dates (Pennsylvania Department of Health, 1983/1997).

28

(PenBsylva.ua Departmen. of Health, 1983/19i>7). pennsylvania
mandate that all students entering kindergarten must have four or more doses of DTP,

with one dose administered on or afler the 4* birthday; three doses of OPV/IPV; two
doses of a measles-containing vaccine (preferably the MMR); one dose of rubella

containing vaccine (preferably MMR), one dose of mumps containing vaccine

(preferably MMR), and 3 doses of HBV. All immunizations must be properly
spaced.
When collecting data, the researcher assigned a reference number to each
student’s immunization record. Data collected from the immunization record
included the student’s date of birth, gender, zip code, and dates of all immunizations.

Collected data was entered into the Clinic Assessment Software Application
(winCASA) computer program developed by the CDC to measure vaccine coverage

rates.
Pilot Study

A pilot study was performed in the same school as the sample group. Ten

immunization records were randomly selected from the 1 grade students.
Immunization records were photo-copied by a school office employee.
Confidentiality was assured by limiting the information maintained on the copies.

Identifying data including students’ names, home addresses, phone numbers, and

names of guardians were eliminated from the copies of students’ immunization
records. Infonualion regarding students’ dates of immunization, date of births,

genders, and zip codes were retained on the record copies.

29

Data Analysis

Data analysis used categorical frequency distribution and the Clinic

Assessment Software Application (winCASA) computer program developed by the
CDC. Steps in the data analysis were the following:
1. Determine the percentage of children with an up-to-date immunization

series for the recommended childhood vaccinations at ages of 12 months, 24 months,
and school entry.

2. Determine the percentage of children with up-to-date immunization series
that includes only the vaccine doses that are properly spaced and valid. Up-to-date
immunization series computed at ages of 12 months, 24 months, and school entry.
3. Determine the percentage of children with age-appropriate immunization

series at ages of 3 months, 5 months, 7 months, 16 months, 19 months, and school
entry.

4. Determine the percentage of children with each single antigen at the age of
12 months, 24 months, and school entry. Single antigens considered are DTP, OPV,

MMR, and HBV.
Summary

This purpose of this study was to determine the immunization rates of
kindergarten students in a rural school district located in northwestern Pennsylvania.
The sample group consisted of 125 rural kindergarten students enrolled in school for

Elected from photo-copies of students’ Certificate of
the year 1998/1999. Data was c<
Immunization Records. Data analysis used categorical frequency distributions and

30
the computer program, Clinical Assessment Software Application (WinCASA), to

determine the percentage rates of immunization coverage. Research Questions,

operational definitions, research design, research consent, and pilot study were also
discussed.

31

Chapter IV

Results
This purpose of this study was to determine the immunization status of a rural

childhood population in northwestern Pennsylvania. This chapter further describes

the sample group and immunization data used for this study. At specified ages the

kindergarten students’ immunization status is discussed in terms of up-to-date
immunization series and age-appropriate immunization series. Percentage of students
having each antigen is also reported.

Sample Group
Of the 125 kindergarten students enrolled in the Pennsylvania rural school

district, three students did not qualify for this study because their birthdays fell before
9-1-92. On the reverse side of the Certification of Immunization Record, no parent or
guardian reported a medical or religious exemption from vaccinations for their child,

therefore it was assumed that the sample group of children could be vaccinated by the
age of school entry (Appendix A).

One hundred and twenty two students qualified for this study. The

distribution of males to females was 49% males to 51% females. Other than being all

kindergarten students in a northwestern Pennsylvania rural school district no other
demographics are known about the student population.
Immunization Data

Immunization data regarding DTP, OPV, MMR, and HBV were collected
using the Certification of Immunization Records of 122 kindergarten students bom

32

between 9-1-92 and 8-31-93. Immunizations administered on or after September 2,
1998 were not included. Immunization dates that included only a month and year
were arbitrarily assigned the 15th of the month for the purpose of this study.

Immunization dates that included only the year were not included. One student out
122 had no proof of immunizations prior to September 2, 1998.
Up-to-Date Immunization Coverage Rates

One of two up-to-date immunization series evaluated included three vaccines:
DTP, OPV and MMR. The second up-to-date immunization series included HBV in

addition to DTP, OPV, and MMR. Percentage of students who had both up-to-date
immunization series was calculated at ages 12 months (9-1-93 to 8-31-94), 24 months
(9-1-94 to 8-31-95) and age of school entry (at least 60 months of age and no more

than 72 months of age by 9-1-98).

National goals of Healthy People 2000 are to have 90% of children age 24
months and 95% of children age of school entry receive a basic immunization series
of DTP, OPV, and MMR. At 12 months of age, 87% of the students had an up-to-

date DTP3:OPV3:MMR0 series (Table 8). At 24 months of age, when the vaccine
DTP4 and MMR1 were suggested, coverage rates dropped to 75%. By the age of

school entry, when proof of immunizations was required for school entry, rates of

coverage increased to 86% for the up-to-date DTP5:OPV3:MMR2 series.

Rates of coverage for up-to-date series with HBV vaccines were 11% to 32%
lower than rates for up-to-date series without HBV. At 12 months, rates ofcoverage

33

Table 8

Coverage Rates of Up-to-Date Immunization Series by Respective Ages

Vaccine Series
Age (months)

’DTP

2OPV

3mmr

Coverage Rates

4hbv

With HBV

Without HBV

2

54%

87%

12

3

2

24

4

3

1

3

52%

75%

5

3

2

3

75%

86%

5School Entry

Note. N= 122 rural kindergarten students bom between 9-1-92 and 8-31-93. Vaccine
Series indicates the name of the vaccine and the number of doses recommended by

the American Academy of Pediatric (AAP) and/or the Centers for Disease Control

and Prevention (CDC) for children by the respective age (AAP, 1991; CDC, 1989;

CDC, 1991; CDC, 1994). Percents are rounded to the nearest whole number.
'DTP = diphtheria and tetanus toxoids and pertussis vaccine. 2OPV = oral poliovirus

4MMR = measles, mumps, and rubella
vaccine. 3HBV = hepatitis B vaccine.

vaccine. 5School Entry

Students were at least 60 months of age and no more than

72 months of age by 9-1-98.

34

At 24 months rates ofcoverage remained at 52%, until age of school entry, when

HBV3 was required for school registration, coverage for the up-to date series
including HBV increased to 75% entrance.
Properly Spaced Doses

A vaccine dose was considered valid when it was administered on or after the
minimum age recommended by the CDC, and the intervals between subsequent doses
are equal to or greater than the minimal period recommended by the CDC (CDC,

1994a). Ten out of 918 vaccine doses administered to the sample group were invalid
because of improper spacing. An additional dose of HBV was administered to two of
five students with an invalid HBV2. An additional dose of OPV was administered to
the student with an invalid OPV2. Revaccination process negated existing invalid

doses and students were considered properly vaccinated at the age of revaccination.
Excluding invalid doses of DTP, OPV, or MMR from up-to-date series

reduced coverage rates for this series by 1% at age 12 months, and by 2% at ages of
24 months and school entry. Excluding invalid vaccine doses of DTP, OPV, MMR or

HBV from up-to-date series reduced coverage rates for this series by 5% at all three
ages being evaluated.

Age-Appropriate Immunization Coverage Rates
For the purpose of this study, an age-appropriate immunization was a vaccine

dose administered within a period up to 30 days after the latest age recommended by
the CDC and/or American Academy of Pediatrics (AAP). One two age-appropriate

series evaluated included the vaccines DTP. OPV, and MMR; the second series

35

included the vaccines DTP, OPV, MMR and HBV. Percentage of students covered
by each age-appropriate immunization series was calculated when students were ages
of 3 months, 5 months, 7 months, 16 months, and 19 months and school entry.

School entry age was at least 60 months of age but not greater than 72 months of age.
Rate of coverage for age-appropriate series is the product of the cumulative

sum of timely administered doses of each vaccine at each age. Therefore, as students

become older, rate of coverage should remain the same or decrease (Table 9). For
this group of students, rate of coverage for the age-appropriate DTP:OPV:MMR
declined from 78% at age 3 months, to 51% at age 7 months, and finally to 33% at

ages of 19 months and school entry. For the age-appropriate immunization series that
also included HBV, rate coverage was low from the onset. As young as 3 months of
age, only 38% were age-appropriately immunized with a DTP1 :OPV1 :MMRO:HBV1

series. Percentage rates for the age-appropriate series that included HBV continued
to fall to 27% at age 7 months, and 18% at ages of 19 months and school entry.

Rates of coverage for age-appropriate immunization series were lower than

rates for up-to-date immunization series. The same vaccine doses in each series
served as the basis for comparisons of the two immunization series. For the age-

appropriate and up-to-date series of DTP4:OPV3:MMR1, 33% of students age 19
months were age-appropriately immunized compared to 75% of students age 24
months who were up-to-date. Rates of coverage for the age-appropriate and up-to-

date immunization series DTP5: OPV3: MMR2 at age of school entry was 33% and
75%, respectively.

36

Table 9

Coverage Rates of Age-Appropriate Immunization Series by Respective Ages

Vaccine Series
Age (months)

’dtp

2OPV

3mmr

Coverage Rates

4hbv

With HBV

Without HBV

3

1

1

1

38%

78%

5

2

2

2

32%

64%

7

3

2

2

27%

51%

16

3

2

1

2

24%

44%

19

4

3

1

3

18%

33%

5

3

2

3

18%

33%

^School Entry

Notes. N

122 rural kindergarten students bom between 9-1-92 and 8-31-93.

Vaccine Series indicates the vaccines and number of doses that are recommended by
the American Academy of Pediatrics (AAP) and/or the Centers for Disease Control

and Prevention (CDC) for children by the respective ages (AAP, 1991; CDC, 1989;

CDC, 1991; CDC, 1994). Percents rounded to the nearest whole number.
’DTP = diphtheria and tetanus toxoids, and pertussis vaccine. 2OPV = oral poliovirus
4MMR = measles, mumps, and rubella.
vaccine. 3HBV = hepatitis B vaccine.

vaccine. 5School Entry

Students were at least 60 months of age and no more than

72 months of age by 9-1-98.

31

Overall, series that included HBV doses were consistently lower than the
series that did not include HBV. For the vaccine series DTP4:OPV3:MMR1 :HBV3,

18% of students age 19 months were age-appropriately immunized compared to 52%

of students age 24 months who were up-to-date. Rates of coverage for age­
appropriate and up-to-date immunization vaccine series of DTP5:OPV3:MMR2:

HBV3 at age of school entry was 18% and 86%, respectively.
Age-appropriate immunization series at 3 months indicate that 78% of the

sample group had had at least one contact with a provider and were administered their

first dose of DTP and OPV. At the same age of 3 months, only 38% were also
administered their first doses of HBV in addition DTP and OPV.
Individual Antigen Coverage Rates

Percentage rate ofcoverage for the individual antigens of DTP, OPV, MMR

and HBV were calculated for students at the ages of 12 and 24 months, and school
entry. Immunizations were not evaluated for their proper spacing or validity.

Of the individual antigens included in this study, HBV had the poorest rate of
coverage (Table 10). At the age of 12 months, 59% of students had had their second

dose of HBV, and by age 24 months, 61% had had their third dose of HBV. Rates of
coverage increased to 86% at age of school entry, when a three-dose HBV series was

required for school.
Individual antigens, DTP, OPV, and MMR, had higher rates of coverage than

HBV but several did not attain the goals of Healthy People 2000. Except for MMR 1
at 90%, students rates of coverage for vaccines recommended at age 24 months were

38

Table 10
Coveiage Rates of Individual Antigens by Respective Ages

Coverage Rates

Vaccine/Dose

DTP 3

12 months

24 months

5School Entry

87%

95%

99%

77%

98%

DTP 4
DTP 5

2OPV 2

86%
96%

97%

99%

OPV3

85%

98%

3MMR 1

90%

98%
93%

MMR2
4HBV 1

67%

78%

98%

HBV 2

59%

75%

95%

61%

86%

HBV 3

Notes. N = 122 rural kindergarten students bom between 9-1-92 and 8-31 93.

Percents rounded to the nearest whole number. Vaccine/Dose indicates the vaccine
and the number of doses. Percents are rounded to the nearest whole number.

'DTP = diphtheria and tetanus toxoids, and pertussis vaccine. 2OPV = oral poliovirus
vaccine. 3HBV = hepatitis B vaccine. 4MMR = measles, mumps, and rubella.
5School entry = Students were at least 60 months of age and no more than 72 months.

of age by 9-1-98.

39

below 90% with DTP4 at 77%, OPV 3 at 85% and HBV 3 at 58%. By the age of
school entry 98% or more students received the antigens DTP 4 or OPV 3.
Remaining individual antigens recommended at age of school entry were MMR 1 at
86%, and DTP5 and HBV3 both at 86%.

Data indicates that of the students who received their first vaccine by the age
of 3 months of age (excluding hospital-given Hepatitis B) 80% completed their up-todate series of DTP4:OPV3:MMR1 by age 24 months. Of the children who received

their first vaccine after 3 months of age (excluding hospital-given Hepatitis B), 57%
received the DTP4:OPV3:MMR1 by age 24 months of age.

Pennsylvania’s Mandated Immunizations for School Entrance
In Pennsylvania, school immunization laws require that kindergarten students

have four or more doses of DTP, with one dose administered on or after the 4th
birthday; three doses of OPV/IPV; two doses of a measles-containing vaccine

(preferably the MMR); one dose of rubella containing vaccine (preferably MMR),

one dose of mumps containing vaccine (preferably MMR), and three doses of

HBV.(Pennsylvania Department of Health, 1983/1997). As of September 2 1998,
77% of the students in this study were compliant with Pennsylvania school

immunization requirements.
Summary
This study used a convenience sample of 122 rural kindergarten students bom

between 9-1-92 and 8-31-93. Immunization data was collected using the school

based Certificate of Immunization Records.

40

Individual antigens had the highest rate of immunization coverage. At age 24
months the percentage of students having specific antigens were 61% with HBV 3,

77% with DTP 4, 85% with OPV 3, and 90% with MMR 1. At the age of school
entry, rates of coverage increased to 98% for DTP4, 99% for OPV3, 93% for MMR2,

and HBV 3 and DTP5 were both at 86%.

Seventy-five percent of students at age 24 months and 86% of students at age
of school entry had an up-to-date immunization series that included doses DTP, OPV,

and MMR. Coverage rates for up-to-date series that included HBV was 52% at 24
months and increased to 75% by the age of school entry. Excluding invalid doses
from up-to-date series reduced the coverage rates for this series between 1% to 5%.

Age-appropriate immunization series had the lowest rates of coverage. As

students matured, the percentage covered with age-appropriate series steadily
declined. For the age-appropriate series that included the vaccines DPT, OPV, and

MMR, rates decreased from 78% at age 3 months to 33% at age 19 months and

school entry. Age-appropriate series that also included HBV had lower the rates of

coverage. For an age-appropriate immunization series that included DTP, OPV,
MMR, and HBV, coverage rate at 3 months of age was 38%; by age of 19 months

and school entry rates rates fell to 18%.

41

Chapter V

Discussion

The purpose of this study was to determine the immunization status of rural
kindergarten students in a northwestern Pennsylvania school district. The results of
this study established baseline data of immunization rates for this rural area in
Pennsyl vania. This baseline data will aid future determinations of immunization

rates. It will also assist evaluations of this area’s progress towards CDC’s

immunization goals to immunize 90% or more of children age 24 months and 95% or
more of children at school age with basic immunization series.

A review of literature included surveys of coverage rates in the nation,
Pennsylvania, and Erie County; research of immunization rates in rural areas; and
research that utilized school-based immunization records to determine immunization
status. Survey studies of the nation, state and Erie County indicated that fewer than

90% of children age 24 months living in these areas had up-to-date immunization
series (CDC, 1995; CDC, 1997a; CDC, 1997b; CDC, 1998b; Erie County Department

of Health, 1999). The surveys also reported that more than 90% of children age 24
months living in the US and Pennsylvania received the antigens DTP3, OPV3, or

MCV1, but less than 90% of children age 24 months received the fourth dose of DTP
and third dose of HBV.

Findings of a study comparing rural and urban immunization coverage rates
reported that one-third of their rural and urban childhood populations were
inadequately immunized (Lowery et al., 1998). Demographic data of this study

42

concluded that underimmunized rural and urban children were of low income
families, have less educated parents, and of a minority race. Findings of a second
study indicated that 44% of the students surveyed in an urban and a rural school

district were not fully immunized (Bradford et. al, 1996). No significant correlation
between demographic data and failure to be fully immunized was possible for this

study. However, according to parents surveyed, the primary reason their children

were not immunized was because they were unaware of needed immunizations.
Finally, a study using school-based immunization records was reviewed. The
school-based study of Zell, Dietz, Stevenson, and Cochi (1994) reported 11% to 58%

of children age 24 months had up-to-date immunization series and 5% to 20% had
age-appropriate immunization series. By the age of school entry, up-to-date
immunization rates increased to 71% to 86%. Improperly spaced doses of vaccines

reduced up-to-date immunization rates for this study by 1% to 8%.
One hundred and twenty two kindergarten students of a rural school district
qualified for this study. Immunization data were collected using the students’
Certificate of Immunization Records. Data of this study for the up-to-date

immunization series included doses of DTP, OPV, and MMR indicated that 75% of
the students at age 24 months and 86% students at age of school entry were covered.

For the up-to-date series that also included HBV only 52% of students at age 24
months and 75% at age of school entry were covered. Rate of the age-appropriate

immunization series included vaccines of DTP, OPV, and MMR was 33% for
children ages of 24 months and school entry. HBV added to the age-appropriate

43

series reduced the coverage to 18% for children age 24 months and school age. At

age 24 months coverage rate for key antigens of DTP4, OPV3 and HBV3 was less
than at 85%. Only MMR1 had a coverage rate of 90%. By age of school entry
individual antigen rates were 98% for DTP4, 86% for DTP5, 98% for OPV3, 93% for

MMR1, and 86% for HBV3.
For this sample group up-to-date and age-appropriate immunization rates were

less than 90% at age 24 and less than 95% at age of school entry. Consequently it is
the conclusion of this study that the group of children were inadequately immunized

to protect them from vaccine-preventable diseases resulting in a dependent care
deficit. Dependent care agencies of health care providers, parents, or health care
system failed to meet the requirements of care to provide the primary prevention from

infectious diseases that being immunizations. Further research is needed to determine
ongoing immunization rates of this rural community, identify barriers to
immunization efforts and therapeutic actions that foster improve immunization

practices.
Conclusions

National goals of Healthy People 2000 are to immunize 90% of children age
24 months and 95% of children age of school entry with a basic immunization series
of DTP, OPV, and MMR (US DHHS, 1991). Estimated national and Pennsylvania
rates for up-to-date series for children age 24 months were 74% to 78% in 1994 and

1995. These rates were similar to findings of this study indicating that 75% of the
sample group at age 24 months (9-1-94 to 8-31-95) had an up-to-date series of

44

DTP4:OPV3:MMR1. In addition this study found that 86% of students at age of
school entry had an up-to-date series of DTP5:OPV3:MMR2. Although the rates of
this study reflect immunization trends in the nation and state, they all fall short of

goals of Heathy People 2000.
Date of birth, sex, and zip codes were the only demographic data collected
from the sample group. Further determinations of the sample group’s demographics

such as family income, parents education level, length of residence in the rural
community, type of community resources and health care providers is needed to

determine if a correlation of demographics characteristics and low immunizations

rates is possible.

Findings of this study suggest that low percentages of children were
immunized with HBV. Rate of up-to-date immunization series with HBV3 was 52%
at 24 months. Rate of coverage for the individual antigen HBV3 at age 24 months

was 61% compared to national rates of 38% in 1994 and 68% in 1995. The
emerging role of HBV for the prevention of hepatitis B infection may account for the

low HBV coverage rates of this study group. In 1991, populations at high-risk for
contracting hepatitis B infections were the primary targets of the CDC’s hepatitis B
infection prevention strategy (CDC, 1991). At the same time, the goal of Healthy

People 2000 was to have immunized only 70% of children age 24 months with HBV

by 1996. It was not until 1994 that HBV was incorporated into the Recommended

Immunization Schedule (CDC, 1994a). For this study group of children who were
age 24 months in the years 1994 to 1995 the Recommended Immunization Schedule

45

had just been revised to include HB V for low-risk infants. It is possible that with the
emphasis of HBV for low risk infants and the update Pennsylvania school

immunization laws that have required a three-dose HBV series for all students
entering school as of 1997/1999, current student populations will have improved rates

of HBV immunizations. Further research with a younger sample group is suggested
to determine if current immunization practices have included HBV for low risk

infants and to evaluate the effect of Pennsylvania school immunization laws.
Up-to-date immunization rates at age 24 months increased by the age of
school entry. Data of this study indicates an increase coverage rate for the up-to-date

immunization series of DTP, OPV, and MMR from 75% covered at the age of 24

months to 86% covered at age of school entry. Up-to-date immunization series
including HBV3 also increased from 52% at age of 24 months to 75% at age of
school entry. Rate individual antigens also were on an rise at age of school entry.
For the antigen HBV3, 86% of the students entering school had received this vaccine

dose. These increased rates from the age of 24 months to the age of school entry are

possibly the product of Pennsylvania school entrance laws as of 1997/1998. These
newer immunization laws required a child to have four or more doses of DTP, one
being administered on or after their 4th birthday, and the antigens OPV3, MMR2, and

HBV3. Prior school immunization laws mandated only the vaccines DTP3, OPV3,
and MMR1 for school entry.

Age-appropriate immunization practices require a health care provider to

adhere to the Recommended Immunization Schedule, simultaneously immunize

46

children, and begin immunizations before a child is 3 months old. At the age of 3
months, 78% of children received their first dose of DTP and OPV compared to 33%
who also received their first dose of HBV. At ages of 19 months and school entry,

more than 66% to 80% of students were not immunized at the ages recommended by
the CDC and/or the AAP. Providers’ hesitancy and reluctance to administer multiple

injections, along with parental objections to simultaneous immunizations may

account for the low rate of age-appropriate coverage.
It is the responsibility of the provider to administer vaccines at the appropriate

intervals. Zell’s study (1994) reported a rate reduction of 1% to 8% when invalid
doses of vaccines were excluded from the for up-to-date series DTP4:OPV3:MMR1.
In this study the exclusion of invalid doses for this same series at age 24 months
reduced its rates by 2%. In addition, this study found that excluding invalid doses

from the up-to-date immunization series with HBV reduced the its rates 5% at all

three ages studied. However, it is unknown whether one or more health care

providers administered the invalid doses to this sample group because data regarding
health care providers was not collected.

Less than 90% of the childhood population of this study at age 24 months was
immunized with an up-to-date or age appropriate immunization series. With less than
optimal immunization rates ofcoverage it is concluded that the children as a group at
age 24 months were inadequately immunized to protect them from vaccinepreventable-diseases. By the age of school entry immunization rates increased but
remained below the 95% rate ofcoverage desired at this age. At age of school entry,

47

only 77% of students were compliant with school immunization requirements at the
onset of school year 1998/1999. Seventy-five percent had up-to-date immunization

series that included the required HBV3 vaccine.
Failure of the combined actions of community, health care providers, and

parents to provide the primary preventative protection of immunization to this

childhood population indicates the existence of a dependent care deficit and
inadequate dependent care agencies. Research is suggested to determine the ongoing

immunization rates of this rural area, identify barriers to immunization efforts, and
evaluate the effectiveness and deficiencies of the dependent care agencies including

parents, health care providers, and community resources.
Recommendations

Health care providers and school nurses play a major role in protecting
children from vaccine-preventable diseases through education and ensuring proper

administration of age-appropriate immunizations. Health care providers are to
educate parents and communities of the benefit to risk ratio of immunizations and the
potential consequences vaccine-preventable diseases. Primary providers are to

immunize according to the Recommended Immunization Schedule and observe age-

appropriate immunization practices that begin before the age of 3 months. Parents’
cooperation is needed to begin their children’s immunizations by age 3 months.

Parents of children not seen by 3 months need oral and written reminders to have
their children seen regularly by a health care provider.

48

Furthermore, providers are to administer all immunizations that can be given
during one visit for that child’s age. Missed opportunities to simultaneously
immunize children create delays in the age-appropriate immunization schedule. All

children’s health contacts are potential opportunities to immunize. At each health

contact providers should review children’s immunizations and discuss needed

immunizations with their parents’.
Further study of future kindergarten and preschool populations of this rural
school district would more clearly identify immunization trends of this rural

community. Sample groups consisting of younger rural preschoolers attending early
intervention school programs or daycare would provide more current determinations

of immunization practices and immunization rates. Research to determine impact of

school immunization laws on immunization rates and immunization practices is also
suggested.
Research that includes determinations of demographic characteristics would
be helpful to identify the specific rural populations at high-risk for

underimmunization. Knowledge of income levels, race, parent’s education, health

care providers, length of residency, preventative care practices, and health care
coverage would further define the children at high-risk for underimmunization and

the health needs of the community.
In conclusion this study served to determine the baseline data of this rural
area. Continued research of this kind is suggested at a local level to better understand
the needs of the community and improve immunization rates.

49

References
American Academy of Pediatrics (1991). Red book: Report of the Committee

on Infectious Diseases. (22nd ed.). Elk Grove Village, II.: author.

Bradford, B. J., Benedum, K. J., Heald, P. A., & Petrie, S. E. (1996).

Immunization status of children on school entry: Area analysis and recommendations
1991. Clinical Pediatrics, 35(5), 237-242.

Centers for Disease Control and Prevention (1989). General recommendations
on immunization. Morbidity and Mortality Weekly Report, 38(13), 205-227.

Centers for Disease Control and Prevention (1991). Hepatitis B virus: A
comprehensive strategy for eliminating transmission in the United States through

universal childhood vaccination. Morbidity and Mortality Weekly Report, 40(No.
RR-13), 1-25.
Centers for Disease Control and Prevention (1994a). General
recommendations on immunization: Recommendations of the Advisory Committee

on Immunization Practices. Morbidity and Mortality Weekly Report, 43(RR-1), 1-38.

Centers for Disease Control and Prevention (1994b). Reported vaccinepreventable diseases - United States, 1993, and the Childhood Immunization
Initiative. Morbidity and Mortality Weekly Report, 43(4), 57-60.

Centers for Disease Control and Prevention (1994c). Update: childhood

vaccine-preventable diseases-United States, 1994. Morbidity and Mortality Weekly
Report, 43(39), 718-720.

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Centers for Disease Control and Prevention (1995). State and national

vaccination coverage levels among children aged 19- 35 months-United States,

April-December 1994. Morbidity and Mortality Weekly Report, 44(33), 613, 619,

621-623.
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vaccination coverage by age 2 years- -linkage of vaccination and WIC services.

Morbidity and Mortality Weekly Report, 45(10), 217-218.
Centers for Disease Control and Prevention (1997a). National, state, and

urban area vaccination coverage levels among children aged 19-35 months—United
States, January-December 1995. Morbidity and Mortality Weekly Report, 46(10),
227-228.
Centers for Disease Control and Prevention (1997b). Status report on the
Childhood Immunization Initiative: National, state, and urban area vaccination
coverage levels among children aged 19-35 months—United States, 1996. Morbidity

and Mortality Weekly Report, 46(29), 657-664.
Centers for Disease Control and Prevention (1997c). Status report on the

Childhood Immunization Initiative: Reported cases of selected vaccine-preventable

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671.

51

Centers for Disease Control and Prevention (1997d). Vaccination coverage by
race/ethnicity and poverty level among children aged 19-35 months - United States,

1996. Morbidity and Mortality Weekly Report, 46(41), 963-969.

Centers for Disease Control and Prevention (1998a). Measles, mumps, and
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rubella syndrome and control of mumps. Morbidity and Mortality Weekly Report,
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Centers for Disease Control and Prevention (1998b). National, state, and

urban area vaccination coverage levels among children aged 19-35 months—United

States, 1997.Morbidity and Mortality Weekly Report, 47(26), 547-554.
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urban area vaccination coverage levels among children aged 19-35 months—United
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Report, 47(6), 108-116.
Centers for Disease Control and Prevention (1998d). Quarterly immunization
table. Morbidity and Mortality Weekly Report, 47(29), 627.

Centers for Disease Control and Prevention (1998e). Varicella-related deaths
among children-United States, 1997. Morbidity and Mortality Weekly Report,
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week April 18-24, 1999 . Erie, Pennsylvania.

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Lowery, N. E, Belansky, E. S., Siegel, C. D„ Goodspeed, J. R., Harman, C.
P., & Steiner, J. F. (1998). Rural childhood immunization: Rates and demographics
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Orem, D. E. (1995). Nursing: Concepts of practice. (5th ed.). St. Louis:
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53

Appendix

54

Appendix A

Certification of Immunization Record
Name

Birthdate

Address

Parent or Guardian

-------------------------------------------------------------------------------- --Telephone_____________________________
Race/Ethnicity
White
Black
Asian or Pacific Islander
American Indian or Alaskan Native
Hispanic Origin: LI Yes UNo
Please Circle Present Grade:

2

1

K

3

4

5

8

7

6

9

10

12

11

Sp. Ed.

PENNSYLVANIA DEPARTMENT OF HEALTH —CERTIFICATEOF IMMUNIZATION
Enter Month, Day, And Year Each Immunization Was Given

____________ VACCINE

DOSES

Diphtheria and Tetanus

/
/
/

Polio
Measles (“Hard") (“Red")

Rubella (“German Measles’’)

1

I

I

2

/

2

/

2

I

2

I

I

3

I

/

/
/

/

3

I

/<

!

or Measles Serology:

Date

Titer

)

or Rubella Serology:

Date

Titer

I

or Mumps disease diagnosed by a physician: Date

I

Mumps

I

I

2

/

Hepatitis B

/

I

2

/

I

3

/

I

I

/

5

I

//

/

To the best of my knowledge, this child has received the minimum required immunizations. Source D Written

Q Verbal

D Both

Date

Signed
(PHYSICIAN, PUBLIC HEALTH OFFICIAL. SCHOOL NURSE, OR THEIR DESIGNEE)
|j-q02.320 Rev, 9/96

Name.

Birthdate.

Address.

Parent or Guardian.

Telephone.
Please Circle Present Grade:

4
5
6
7
8
9
10
3
2
1
K
STATEMENT OF EXEMPTION TO IMMUNIZATION LAW

11

12

Sp. Ed.

MEDICAL EXEMPTION
The physical condition of the above named child is such that immunization would endanger life or health.

Signed

—------ - --------- -------------------

(PHYSICIAN)

Date

RELIGIOUS EXEMPTION

(Includes a strong moral or ethical conviction similar to a religious belief.)
f h

bove named child adheres to a religious belief whose teachings are opposed to such immunizations.

Parent or guan
State your reason for requesting a religious exemption-------------------------------------------------------------------- ———

Da
Parent or guardian)

Signed