• unlimited access with print and download
    $ 37 00
  • read full document, no print or download, expires after 72 hours
    $ 4 99
More info
Unlimited access including download and printing, plus availability for reading and annotating in your in your Udini library.
  • Access to this article in your Udini library for 72 hours from purchase.
  • The article will not be available for download or print.
  • Upgrade to the full version of this document at a reduced price.
  • Your trial access payment is credited when purchasing the full version.
Buy
Continue searching

Factors influencing childhood vaccination in Nigeria

ProQuest Dissertations and Theses, 2011
Dissertation
Author: Pauline Ann Marie Harvey
Abstract:
Despite Nigeria's adoption of the World Health Organization's Expanded Programme on Immunization, many children remain unvaccinated. Data from the 2008 Nigeria Demographic and Health Survey revealed DPT3 and OPV3 coverage below 40%. The purpose of this quantitative study was to determine the vaccination status of Nigerian children with acute flaccid paralysis (AFP), and to explore sociodemographic factors associated with un- or under-vaccination. Utilizing the social ecology model (SEM) theory, this retrospective cross-sectional study of 5,501 AFP cases in Nigeria in 2009 and analysis of the 384 cases determined to be polio was conducted to address 6 primary research questions. Findings indicated that vaccination status of AFP cases varied by region of residence. There was a difference in reported number of OPV doses received by WPV cases, with 3 doses of OPV reported at paralysis onset, versus 1 OPV dose reported after laboratory diagnosis of polio for the same child. Children living in proximity to a health facility with routine immunization services were more likely to be vaccinated. A child's gender, or a parent's religious affiliation did not affect vaccination status of AFP cases. Individual, community, and societal factors as held by SEM theory were associated with vaccination status. In multivariate analyses, a child's age and region of residence were predictors of vaccination status. This study contributes to social change by identifying areas of Nigeria where vaccination efforts need to be expanded. In the broader social context, reducing the proportion of unvaccinated children in Nigeria will reduce vaccine preventable diseases in this population, and move Nigeria and the world closer to the goal of poliomyelitis eradication.

i Table of Contents

List of Tables…….……………………...………………………………………………..vi List of Figures……………………………………………………...…………………….vii Chapter 1: Introduction to the study……………….……………………………………..1 Background………………………………………………………………………………..1 Vulnerable Children…………………………………………………………….....1 Vaccine Efficacy…………………………………………………………………..3 Statement of the Problem……………………………………………………………….…3 Background of the Problem……………………………………………………………….4 AFP Surveillance………………………………………………………………….4 Organization of the AFP Surveillance System……………………………………5 AFP Cases in 2009………………………………………………………………...6 Nature of the Study………………………………………………………………………..7 Research Questions and Null Hypotheses………………………………………………...8 Assessing Vaccination Coverage of AFP Cases…………………………………………..9 Purpose of the Study……………………………………………………………………..10 Theoretical Framework……………………………………………………………….….11 Operational Definitions……………………………….………………………………….13 Acute flaccid paralysis…………………………………………………………...13 Immunization coverage rates…………………………………………………….13 Polio………………………………………………………………………...........14 Up-to-date………………………………………………………………………..14

ii Assumptions and Limitations……………………………………………………………14 Assumptions……………………………………………………………………...14 Limitations……………………………………………………………………….15 Delimitations and Scope…………………………………………………………………15 Significance of the Study……………………………….………………………………..16 Summary of Chapter 1…………………………………………………………………...17 Chapter 2: Literature Review…………..………………………………………………..19 Introduction………………………………………………………………………………19 Theoretical Foundation…………………………………………………………………..20 Content of the Review…………………………………………………………………...21 Organization of the Review……………………………………………………...21 Strategy of the Review………………………………………………………...…21 Relevancy to the Problem Statement…………………………………………………….22 Vaccines and Immunizations…………………………………………………….23 Immunization Efforts in Africa…………………………………………………..27 Polio Vaccines…………………………………………………………………...35 Global Polio Eradication…………………………………………………………38 Nigeria, Childhood Vaccinations, and Polio……………………………………..47 Summary…………………………………………………………………………………54 Chapter 3: Research Method………….…………………………………………………56 Introduction………………………………………………………………………………56 Research Design and Approach………………………………………………………….58

iii Justification for Using this Design and Approach……………………………….58 Target Population, Setting, and Sample………………………………………………….59 Sample Size………………………………………………………………………60 Eligibility Criteria for Participants……………………………………………….60 Characteristics of the Selected Sample…………………………………………..61 Instrumentation…………………………………………………………………………..61 Name and Type of Instrument…………………………………………………...61 Information collected on the CIFs and DCIFs…………………………………...62 Location of Data…………………………………………………………………62 Data Collection and Analysis…………………………………………………………….62 Independent Variables…………………………………………………………...62 Dependent Variable……………………………………………………………...63 Confounding Variables…………………………………………………………..64 Data Analysis…………………………………………………………………….64 Research Questions and Hypotheses…………………………………………………….64 Statistical Methods……………………………………………………………………….68 Ethical Issues and Measures to Protect Participants‘ Rights……………………….........69 Summary……………………………………………………………………………........69 Chapter 4: Results……...………………………………………………………………..71 Introduction………………………………………………………………………………71 Data Collection………………………………………………………………...………...71 Methodology……………………………………………………………………………..72

iv Demographic Characteristics of Study Population………………………………………72 Data Analyses……………………………………………………………………………76 Null Hypotheses Tested…………………………………………………………….........77 Multivariate Analysis…………………………………………………………………….83 Summary of Results……………………………………………………………………...85 Independent Variables…………………………………………………………………...85 Region of Residence of AFP Cases……………………………………………...85 Gender of AFP cases……………………………………………………………..85 Parental religious affiliation of WPV cases……………………………………...85 Reported OPV doses before versus after laboratory confirmation of wild poliovirus infection……………………………………………………………...86 Zero-dose status of wild poliovirus cases versus non-polio cases……………….86 Chapter Summary………………………………………………………………………..87 Chapter 5: Discussion……...……………………………………………………………88 Overview and Summary of Findings…………………………………………………….88 Methodology……………………………………………………………………………..88 Findings………………………………………………………………………………….90 Interpretation of Independent Variables…………………………………………………91 AFP Vaccination Status and Region of Residence………………………………91 AFP Vaccination Status and Gender……………………………………………..92 WPV Vaccination Status and Parental Religious Affiliation……………………93 Change in Reported Vaccination Status after Polio Diagnosis…………………..94

v Vaccination Status and Living Near to an EPI-providing Health Facility……….95 Zero-dose Status of Polio and non-Wild Poliovirus cases……………………….95 Implications for Social Change and Recommendations for Action……………………..95 Limitations of the Study………………………………………………………………….98 Recommendations for Future Research……………………………………………….....99 Conclusions……………………………………………………………………………..100 References..….………………………………………………………………………….103 Appendix A: Permission to reprint published table…………………...……………….121 Appendix B: WHO-Nigeria AFP Case Investigation Form……………...……………123 Appendix C: WHO-Nigeria DCIF Form……...……………………………………….126 Curriculum Vitae……...………………………………………………………………..135

vi List of Tables Table 1. Reported Cases of Paralytic Poliomyelitis in the United States, 1951 – 1983...37 Table 2. Analytic Data Table……………………………………………………………67 Table 3. Characteristics of Acute Flaccid Paralysis (AFP) Cases in Nigeria in 2009..…73

Table 4. Characteristics of Wild Poliovirus (WPV) Cases in Nigeria in 2009……….…75

Table 5. Vaccination Status of Acute Flaccid Paralysis Cases by Region of Residence..78 Table 6. Reported Vaccination Status of Acute Flaccid Paralysis Cases in Nigeria in 2009, by Gender…………………………………………………………..…….79 Table 7. B, Standard Error, Beta, Wald statistic, and Significance Level (P Value) Results for Variables Through Multiple Regressions………………………….84 Table 8. The Result of R squared through Multiple Regressions……………………….84

vii List of Figures Figure 1. Flow Diagram of Acute Flaccid Paralysis (AFP) Cases and Wild Poliovirus (WPV) cases in Nigeria in 2009…………………………...………………….……..72

1

Chapter 1: Introduction to the Study Background of the Study

Immunization is one of the greatest public health achievements of the 20 th

century. The World Health Organization (WHO, 2010) and the United Nations Emergency Children‘s Fund (UNICEF, 2010) estimated that more than 2 million deaths are prevented each year through the use of immunizations. Through WHO‘s Expanded Programme on Immunization (EPI), the use of vaccines against six childhood killer diseases is promoted in national childhood immunization programs. Since the inception of EPI, vaccination programs have been estimated to reach 75% of the world‘s children, and WHO and UNICEF (2005) estimated that an additional 4 million child deaths could be prevented annually, if vaccination efforts are scaled up. Vulnerable Children By the turn of the 21 st century, about one-fifth of children worldwide were unvaccinated, and by 2006 the bulk of the world‘s unvaccinated children were said to reside in some of the most populous countries – China, India, Indonesia, and Nigeria (WHO, 2006). The most recent Nigeria Demographic and Health Survey ([NDHS], 2009) estimated the proportion of children that are up-to-date on all their routine immunizations to be 23% by the age of 23 months, with broad geographic variations in estimates. Almost one-third of children in households that participated in the NDHS (2009) reportedly received none of the EPI vaccinations. However, current national estimates (WHO-Nigeria, 2010) revealed DPT3 coverage of 71%, and OPV3 coverage of 62%, with lower coverage noted across Northern States, and higher coverage noted for

2

receipt of DPT vaccinations as compared with OPV, as noted both in the 2008 NDHS and Nigeria routine immunization data (WHO-Nigeria, 2010). Nigeria is one of four remaining endemic countries for wild polio virus transmission. Polio is a highly infectious viral disease, which occurs worldwide (Plotkin & Orenstein, 2007). Most cases are seen during the hot humid months, with the virus infecting all susceptible individuals (Sabin, 1949; Nathanson, 1984). Paralysis is seen in about 1% of all infections (Bernier, 1984). Transmission usually occurs via the fecal-oral route (GPEI, 2010; Plotkin & Orenstein, 2007). Immunity against polio is conferred through immunization or natural infection, with immunity to one type not necessarily resulting in immunity to the remaining two types (Plotkin & Orenstein, 2007). Achieving vaccine-induced immunity requires at least three doses of OPV, and even a higher number of doses through mass vaccination campaigns in endemic countries such as Nigeria, where persistent circulation of the virus has never been interrupted (Plotkin & Orenstein, 2007; WHO/UNICEF, 2005). With model polio vaccination campaigns in the Americas in the last half of the 20 th century resulting in the interruption of wild poliovirus circulation in that region, the WHO (World Health Assembly, 1988) launched a global effort to eradicate polio. At the start of the effort, polio was endemic in more than 125 countries across five continents, and paralyzed more than 1,000 children every day (UN, 2002; WHO, 2010). By the end of 2009, there was more than a 99% reduction in cases detected worldwide, with only four countries remaining endemic – Pakistan, Afghanistan, India, and Nigeria (WHO, 2010). At the end of 2010, a total of 968 cases of wild poliovirus were confirmed across

3

the globe (WHO-GPEI, 2011). During 2009, 1,604 wild poliovirus cases were reported (WHO-GPEI, 2011). Much of this decline is due to significant progress in Nigeria in reaching more children with OPV, though there was an outbreak of polio in Tajikistan in 2010 with over 458 cases, as well as large outbreaks in Angola and the Democratic Republic of the Congo (WHO, 2010). Prior to this outbreak, Tajikistan had not reported a single polio case in more than a decade (WHO, 2010). Vaccine Efficacy Jenkins et al. (2008) estimated field efficacies for monovalent and trivalent formulations of oral polio vaccine utilized within immunization campaigns in Nigeria. The per-dose vaccine efficacy of monovalent 1 Oral Polio Vaccine (mOPV1) was determined to be 67%, as compared to 16% per dose for trivalent Oral Polio Vaccine (tOPV) which is formulated to build immunity to all three serotypes of polio following the administration of a birth dose and three additional doses (Jenkins et al., 2008). Despite the availability of potent vaccines, many children in Nigeria remain unvaccinated (WHO-Nigeria, 2010). Reasons for this phenomenon vary, with misconceptions about the safety of the vaccine, cultural, or religious aversions to vaccine acceptance or use, and lack of awareness about the availability of immunization services voiced as possible reasons for children remaining unvaccinated (Renne, 2006; Yahaya, 2007).

Statement of the Problem In 2009, Nigeria had the highest incidence of confirmed wild poliovirus cases in the world (WHO-GPEI, 2010). Routine immunization coverage against polio and other childhood vaccine preventable diseases falls well below nationally established targets

4

(WHO-Nigeria, 2010). Variations in coverage are observed across Nigeria with certain factors appearing to play a role – such as level of education, religion, cultural practices, and accessibility to vaccination services (WHO-Nigeria, 2010). The research problem addressed in this study was to determine factors which influence childhood vaccination in Nigeria. Background of the Problem AFP Surveillance AFP surveillance is the process for detecting and investigating all AFP cases in children under 15 years, or in any individual in whom a clinician suspects polio (WHO- GPEI, 2010). The purpose of AFP surveillance is to identify and document whether or not poliovirus is present or absent in a country (WHO-GPEI, 2010) and health workers are trained to recognize AFP, rather than specifically looking to diagnose polio. As there are several potential differential diagnoses for AFP (Guillan-Barre syndrome, transverse myelitis, traumatic neuritis, and infection with nonpolio enterovirus), it is important that all cases of AFP be found and stool from each AFP case tested for the presence of wild poliovirus (FMOH, 2007). This surveillance system should be sensitive enough to detect polio if indeed it exists, and will be the basis upon which global certification of polio eradication will be made (Plotkin & Orenstein, 2007; WHO-GPEI 2010). All cases of AFP should be reported, and stool specimens tested in the laboratory to avoid missing cases of polio (Centers for Disease Control and Prevention [CDC], 2009). Among AFP cases, some distinguishing characteristics of paralytic polio include asymmetric flaccid paralysis, fever at onset, rapid progression of paralysis, residual

5

paralysis after 60 days, and preservation of sensory nerve function, though for most infected people no symptoms are exhibited, or they go unrecognized (Plotkin & Orenstein, 2007; WHO-GPEI, 2010). However, only through viral isolation of poliovirus from stool specimens can a confirmatory diagnosis of polio be made (CDC, 2009). Organization of the AFP Surveillance System Within over 8,000 health facilities designated as AFP sentinel reporting sites in Nigeria, a focal point is designated to coordinate surveillance activities (FMOH, 2007). The individual functioning as the focal point within the sentinel reporting site serves as the primary source of information regarding patients admitted or seen in the health facility suspected to be an AFP case (FMOH, 2007). These facilities include but are not limited to general hospitals, teaching hospitals, physiotherapy centers, and private health facilities (FMOH, 2007). These sites are visited by surveillance officers who review health facility records, visit patient wards, and conduct interviews with health workers to check for suspected cases of AFP (FMOH, 2007). Clinicians in these facilities are sensitized and mobilized to report AFP. Once an AFP case is detected, immediate report and completion of the AFP Case Investigation Form (CIF) should be done (FMOH, 2007). Further, two stool specimens should be collected 24-48 hours apart, appropriately packaged and sent to one of two regional WHO-accredited labs in Nigeria for primary isolation of wild poliovirus (FMOH, 2007). If polio is isolated, then the sample is further processed to undergo intratypic differentiation to determine which of the three types of poliovirus infection is present ([Type 1, Type 2, or Type 3], FMOH, 2007).

6

In the event that an AFP case is laboratory confirmed as polio, then a subsequent detailed case investigation is conducted 60 days following the onset of paralysis to determine whether or not residual paralysis is present in the individual (FMOH, 2007). Residual paralysis is typically uncommon for nonpolio causes of AFP (FMOH, 2007). This Detailed Case Investigation Form (DCIF) should also be completed for cases of AFP where stool specimen were inadequate and would therefore limit the ability to isolate virus in the lab, for cases confirmed to be circulating vaccine-derived poliovirus, and when vaccine-strains of OPV are detected in the stool (FMOH, 2007). This follow- up investigation is conducted by trained health personnel to determine whether or not there is persistent residual paralysis (FMOH, 2007). In 2009, a total of 5,501 AFP cases were detected in Nigeria, and 790 detailed case investigations completed at least 60 days following paralysis onset (WHO-Nigeria, 2010). AFP Cases in 2009 With over 5,500 children affected by acute flaccid paralysis last year (one of the signalling symptoms of potential infection with wild poliovirus), the need exists to understand the vaccination status of these children (both those which were confirmed to be infected with wild poliovirus and those determined to be polio-free), to elucidate factors which potentially influence vaccination based on case history, to determine variations which may be present (such as by geographical region of residence, gender, and religious affiliation), and to consider these and other areas for further research.

7

Nature of the Study The method of inquiry for this study was a retrospective, cross-sectional quantitative study of children who experienced AFP in Nigeria in 2009, and for whom a clinical investigation was completed. The cross-sectional study design is ideal for descriptive studies, and also to investigate associations between risk factors and a particular outcome (Creswell, 2003). This is useful in generating further hypotheses for future research (Creswell, 2003). In addition, data from the database of the 60-day follow-up detailed case investigation forms was accessed. These data are in the custodianship of the WHO, Nigeria Country Office and are maintained within the Expanded Programme on Immunization Unit. AFP surveillance commenced in Nigeria in 1998 (CDC, 1999). This study considered the vaccination status of children in Nigeria who experienced AFP in 2009, and explored sociodemographic factors which may appear to be associated with un- or under-vaccination. The study involved secondary analysis of data collected at the time of paralysis onset, and for those confirmed to be polio, additional data at 60-day follow-up postparalysis onset. The confirmation of poliovirus infection is based on worldwide-accepted WHO standardized virologic criteria, where testing of two stool samples for each AFP case is conducted by a WHO-accredited laboratory (CDC, 2009). My research population was derived from individuals who suffered from AFP in Nigeria in 2009, and who were notified for clinical investigation by Disease Surveillance

8

and Notification Officers (DSNOs) working in each Local Government Authority (LGA), or by other community members who notified authorities of the child experiencing AFP. Research Questions and Null Hypotheses 1. Is there a relationship between reported vaccination status of AFP cases with geographical region of residence? H 01 : There is no difference in reported vaccination status by region of residence. H a1 : Reported vaccination status differs by region of residence. 2. Is there an association between reported vaccination status of AFP cases and gender? H 02 : There is no difference in reported vaccination status by gender. H a2 : Reported vaccination status of AFP cases varies by gender. 3. Is there an association between reported vaccination status of confirmed wild polio virus cases and parental religious affiliation? H 03 : There is no difference in reported vaccination status of confirmed wild polio virus cases by parental religious affiliation. H a3 : Reported vaccination status of confirmed wild polio virus cases varies by parental religious affiliation. 4. Does a diagnosis of a child being infected with wild poliovirus result in a change in reported doses of oral polio vaccine at the 60-day follow-up investigation as compared to the initial case investigation report? H 04 : There is no difference in reported OPV doses of AFP cases before versus after laboratory confirmation of wild poliovirus infection.

9

H a4: Reported number of OPV doses differs before versus after laboratory confirmation of wild poliovirus infection. 5. For confirmed cases of polio, is there an association between vaccination status and living in proximity to a health facility which offers EPI services? H 05 : There is no association between reported vaccination status and living near to a health facility that offers EPI services. H a5 : There is an association between reported vaccination status and living near to a health facility that offers EPI services. 6. Are parents of children infected with wild poliovirus more likely to report zero-dose of OPV at the onset of paralysis as compared with parents of nonpolio children? H 06 : There is no difference in the proportion of zero-dose OPV reported at onset of paralysis between children infected with wild poliovirus and those not infected with polio. H a6 : There is a difference in the proportion of zero-dose OPV reported at onset of paralysis between children infected with wild poliovirus and those not infected with polio. Assessing Vaccination Coverage of AFP Cases While the AFP and the DCIF databases have been primarily utilized in programmatic activities, a comprehensive study of variables to determine regional variations, parental faith practices, and gender differences in vaccination against polio has not yet been conducted. Researchers have attempted to explore vaccination behavior

10

in Nigeria (Antai, 2009; Gage, Sommerfelt, & Piani, 1997), and historical events leading to the temporary suspension of immunization activities in Northern Nigeria in 2004 (Ahmad, 2004; Jegede, 2007; Renne, 2006; Yahaya, 2005), but no researcher has studied these issues utilizing the data as reported for AFP cases. A lack of polio vaccination is one of the primary contributing factors to poliovirus infection (CDC, 2009). This presents an ideal opportunity to determine characteristics associated with lack of acceptance of this and potentially other childhood vaccines. Purpose of the Study

My goal in proposing this research was to assess vaccination coverage against polio disease in children who experienced AFP in 2009. Of further importance was to determine the parental report of child‘s vaccination status against poliovirus at the onset of paralysis, and to see if this report is maintained during 60-day follow-up visits to parents whose children were confirmed to have wild poliovirus infection. Finally, understanding the role of distance to nearest health facility offering routine immunization services, to the vaccination status of AFP cases was important to determine accessibility challenges. This body of research will contribute to understanding parental reporting of childhood vaccination against polio, and to determine contributing factors such as region of residence, and proximity to a health facility which offers routine immunization services, based on data collected on the AFP Case Investigation Form, and the 60-day follow-up Detailed Case Investigation Form. Findings from this research can help guide national and local-level efforts aimed at increasing community knowledge, awareness, and demand for childhood vaccinations,

11

with the aim of increasing national childhood vaccination coverage. Addressing these barriers may help to increase uptake of childhood vaccines, thereby reducing the burden of childhood vaccine-preventable diseases and improving child health and survival. Results from this research will be shared with various local stakeholders including government, community, traditional, and religious leaders, as well as caregivers. Agencies involved in immunization promotion and service delivery will be better able to tailor strategies to address factors identified to be associated with un- or undervaccination. Theoretical Framework The theoretical framework underlying this study was the social ecology model (SEM), which serves as a foundation of inquiry into the multiple effects and interrelatedness of social elements within the environment on health behavior and outcome (CDC, 2007). The four-level social ecology model includes theoretical concepts of the role of individual, relationship, community, and societal factors (CDC, 2007). Several public health prevention research studies have utilized the SEM approach, including activities led by the U.S. Centers for Disease Control and Prevention (CDC, 2007) particularly in the area of violence prevention. An adaptation of the SEM was utilized in this study to test the proposed hypotheses in the context of the child‘s environmental influences on vaccination status. This adaptation, the ecological systems theory (EST), was developed by Bronfenbrenner (1977; 1979) and was designed to explain how a child‘s growth and development is dependent on factors innate to the child and his/her environment. Grounded in social and

12

cognitive psychology, EST holds that the health and developmental outcomes of children are influenced by various ecological systems (Bronfenbrenner, 1977). The EST model holds that various levels or aspects of a child‘s environment influence their development, such as the immediate system within which the child lives, including the parental/family relationships and a school or daycare (microsystem) (Bronfenbrenner, 1977). The next level is the mesosystem, which looks at how different parts of the microsystem work together to support the child (Bronfenbrenner, 1977). The next level is the exosystem within which such factors as the community wherein the child resides, and extended family members are considered to contribute to child‘s health and well-being (Bronfenbrenner, 1977). Finally, at the macrosystem level, cultural values and broader social attributes can have a large influence on the child (Bronfenbrenner, 1977). These levels tie-in closely with the four-level conceptual approach offered through the SEM (CDC, 2007). At the various levels within the model, positive or negative contributions to the child can result. Within the context of polio eradication efforts in Nigeria, these four levels of a child‘s environment may contribute towards childhood vaccination. Key independent variables explored in this research were mapped to the four levels within the model as follows: (a) INDIVIDUAL: OPV doses, Gender, (b) RELATIONSHIP: Religion, (c) COMMUNITY: Residence, EpiDistance, and (d) SOCIETAL: Religion, Residence. Within this EST theoretical framework, it is important to recognize how poliomyelitis is perceived by many population groups in Nigeria, and the role that the elements within the four-level SEM plays in relation to

13

childood vaccination status and impact on child health. Behaviors towards childhood immunization, and particularly acceptance of routine doses of Oral Polio Vaccine for the prevention of polio, falls below national annual targets (WHO-Nigeria, 2010). Operational Definition of Terms Acute flaccid paralysis: AFP is the one of the clinically defining features following infection with wild poliovirus (Heymann, 2008). It involves the sudden onset of loss of muscle tone and weakness in the body (Heymann, 2008). Any muscle may be involved, though those of the arms and/or legs are most affected (Heymann, 2008). Presence of AFP raises the index of suspicion of infection with polio, particularly in those countries which remain endemic. The case definition for acute flaccid paralysis is as follows: Any child under 15 years with weakness or floppiness of one or more limbs, or any person in whom a clinician suspects polio (CDC, 2004). AFP may also occur as a result of other diseases or conditions (Heymann, 2008). Immunization coverage rates: Immunization coverage rates reflect the percentage of children who have reportedly received vaccinations against specific vaccine- preventable diseases by a certain age (WHO/UNICEF, 2010). This is ideally measured through children‘s immunization records which are completed at each vaccination visit. The Nigerian National Routine Immunization Schedule reflects that before a child reaches 1 year of age the following vaccines should have been received: one dose of BCG, four doses of OPV, three doses of DPT and HBV respectively, one dose of Measles, and one dose of Yellow Fever (WHO, 2005). In addition, the child should also have received two doses of Vitamin A supplementation (WHO, 2005).

14

Polio: A viral infection most often recognized by the acute onset of flaccid paralysis (Heymann, 2008). The infection occurs in the gastrointestinal tract, spreading to the regional lymph nodes, and in some cases, to the central nervous system (CCDM, 2008). It occurs only in humans and is primarily spread person-to-person through the fecal-oral route (Heymann, 2008). It is prevented through vaccination with oral poliovirus vaccine, or inactivated poliovirus vaccine (Plotkin & Orenstein, 2007). Up-to-date: Up-to-date recognizes a child having completed the recommended series of routine immunizations by the age of 1 year (WHO, 2010). Specifically in Nigeria this includes one dose of BCG, three doses of DPT, four doses of OPV (including a birth dose), three doses of HBV, 1 dose of Measles, and one dose of Yellow Fever vaccines respectively (GAVI, 2004). Assumptions

The following assumptions were made in this study: 1. This was a cross-sectional study of children reported in the 2009 AFP Surveillance Database, and the Detailed Case Information Form Database in the Federal Republic of Nigeria. 2. Childhood vaccinations are an accepted strategy by the Nigeria National Primary Health Care Development Agency to prevent vaccine-preventable diseases in children in Nigeria. 3. AFP surveillance is the gold standard for detecting possible cases of wild poliovirus infection.

15

4. Confirmation of wild poliovirus infections in Nigeria is done by WHO- accredited laboratories and/or by the Enterovirus Laboratory of the CDC. Limitations

The following limitations were acknowledged for this study: 1. The study was based on a sample of children who were reported to the WHO AFP and DCIF databases in 2009. 2. Vaccination history was based on maternal report at time of clinical investigation or follow-up of the child experiencing AFP. This history often is based on self-report, rather than evidenced by completed Child Health Card. 3. Distance to nearest health facility offering immunization services was estimated by the local investigating officer. Delimitations and Scope This study looked at the vaccination status of children who experienced AFP in 2009, as well as cases which completed a 60-day follow-up investigation to determine extent (if any) of residual paralysis. The primary purpose of the study was to assess childhood vaccination status against polio, and to determine factors (such as area of residence, gender, parental religious affiliation) which may be associated with un or under-vaccination. The delimitations of this study were 1. The study was delimited to a quantitative, cross-sectional study design.

Full document contains 159 pages
Abstract: Despite Nigeria's adoption of the World Health Organization's Expanded Programme on Immunization, many children remain unvaccinated. Data from the 2008 Nigeria Demographic and Health Survey revealed DPT3 and OPV3 coverage below 40%. The purpose of this quantitative study was to determine the vaccination status of Nigerian children with acute flaccid paralysis (AFP), and to explore sociodemographic factors associated with un- or under-vaccination. Utilizing the social ecology model (SEM) theory, this retrospective cross-sectional study of 5,501 AFP cases in Nigeria in 2009 and analysis of the 384 cases determined to be polio was conducted to address 6 primary research questions. Findings indicated that vaccination status of AFP cases varied by region of residence. There was a difference in reported number of OPV doses received by WPV cases, with 3 doses of OPV reported at paralysis onset, versus 1 OPV dose reported after laboratory diagnosis of polio for the same child. Children living in proximity to a health facility with routine immunization services were more likely to be vaccinated. A child's gender, or a parent's religious affiliation did not affect vaccination status of AFP cases. Individual, community, and societal factors as held by SEM theory were associated with vaccination status. In multivariate analyses, a child's age and region of residence were predictors of vaccination status. This study contributes to social change by identifying areas of Nigeria where vaccination efforts need to be expanded. In the broader social context, reducing the proportion of unvaccinated children in Nigeria will reduce vaccine preventable diseases in this population, and move Nigeria and the world closer to the goal of poliomyelitis eradication.