Project – Assessment of Factors Influencing Timely Completion of Routine Immunization Among Children Under Five in Selected Primary Health Centres in Jos North LGA, Plateau State

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Immunization is one of the most effective public health interventions for preventing infectious diseases and reducing childhood morbidity and mortality. Through vaccination, children are protected against a range of vaccine-preventable diseases, including tuberculosis, poliomyelitis, diphtheria, pertussis, tetanus, hepatitis B and measles. The importance of immunization extends beyond the protection of individual children because high levels of vaccination contribute to community protection and reduce the likelihood of outbreaks. The World Health Organization (WHO, 2020) therefore identifies immunization as a fundamental component of primary health care and an important intervention for achieving global child-survival goals.

However, the effectiveness of an immunization programme depends not only on whether children eventually receive vaccines but also on when they receive them. Timely vaccination ensures that children receive protection during the period when they are most vulnerable to vaccine-preventable diseases. Bailie et al. (2009) emphasized that timeliness of immunization is important for achieving the protective effects of vaccines at both individual and population levels. Consequently, a child who receives a vaccine several weeks or months after the recommended age may be recorded as vaccinated but may have remained unnecessarily vulnerable during the period of delay.

Timely completion of routine immunization refers to the receipt of the recommended childhood vaccines at the appropriate ages and intervals specified in the national immunization schedule. It involves both starting vaccination at the recommended time and returning for subsequent doses when they are due. This distinction is important because conventional immunization coverage may classify a child as vaccinated without considering whether the vaccine was received on schedule. Sadoh and Eregie (2009) demonstrated the importance of this distinction in Nigeria, reporting that 18.9% to 65% of children in their study experienced delays in receiving different vaccines and that only 44.3% were fully immunized.

The problem of delayed vaccination is significant because children are particularly vulnerable to infectious diseases during infancy and early childhood. Vaccines administered according to the recommended schedule are designed to provide protection at specific stages of a child’s development. When vaccination is delayed, the period during which the child remains susceptible to infection may be prolonged. Sadoh and Eregie (2009) noted that timely receipt of vaccines is necessary to achieve maximum protection against vaccine-preventable diseases. Their findings also suggested that children who started immunization early were more likely to complete the vaccination schedule.

Nigeria has made considerable efforts to improve childhood immunization through routine immunization programmes delivered primarily through the primary healthcare system. Nevertheless, childhood vaccination coverage remains uneven across geographical and socioeconomic groups. Adeloye et al. (2017), in a systematic review and meta-analysis of childhood immunization in Nigeria, found considerable variation in immunization coverage across the country and identified individual and contextual determinants associated with vaccination uptake. These findings demonstrate that the availability of a national immunization programme does not automatically ensure that every child receives vaccines completely and at the recommended time.

The issue of timely immunization is particularly important in Nigeria because some children begin vaccination but fail to return for subsequent doses at the recommended time. This may result in prolonged periods of inadequate protection and may ultimately lead to incomplete immunization. In a clinic-based Nigerian study, Sadoh and Eregie (2009) found that approximately 30% of children presented after four weeks of age for their first immunization, while considerable proportions experienced delays in subsequent vaccines. These findings demonstrate that delayed vaccination can occur at several stages of the immunization schedule.

Caregiver knowledge and awareness are among the factors that may influence timely immunization. Caregivers need to understand the importance of vaccination, know when each vaccine is due and recognize the consequences of missing scheduled appointments. Oladepo et al. (2019), in a study of Nigerian rural mothers, found that poor knowledge of routine childhood immunization constituted an important challenge to immunization completion. The study also examined mothers’ attitudes toward the use of reminder text messages for promoting timely completion, demonstrating the potential value of communication technologies in supporting vaccination schedules.

The relationship between knowledge and actual immunization behaviour is, however, not always straightforward. A caregiver may understand the benefits of immunization but still fail to take a child for vaccination on the scheduled date because of transportation difficulties, work commitments, illness, household responsibilities or other competing demands. Therefore, assessment of timely immunization needs to examine knowledge alongside socioeconomic and practical circumstances.

Socioeconomic conditions can influence access to immunization services. Families with limited income may find transportation expenses difficult to meet, especially when health facilities are located far from their homes. Caregivers who depend on daily income may also be reluctant to spend several hours at a health facility because of long waiting times. Antai (2009), using a multilevel analysis of Nigerian data, demonstrated that childhood immunization uptake is influenced by both individual and contextual factors, highlighting the importance of looking beyond individual caregiver characteristics.

The physical accessibility of healthcare facilities can also influence timely vaccination. Distance between the household and the health facility, availability of transportation and the cost of travelling can determine whether caregivers are able to attend immunization sessions when vaccines are due. This issue is particularly relevant in communities where caregivers may have to travel considerable distances to reach facilities providing routine immunization.

Health-system factors are equally important. A caregiver may arrive at a health facility on the correct date but fail to vaccinate the child because of vaccine stock-outs, absence of trained health workers, changes in clinic schedules or other service-related problems. Evidence from Jos specifically demonstrates that health-system conditions can affect vaccination timeliness. Danjuma et al. (2020), studying at-birth vaccination timeliness among newborns in the highlands of Jos, North-Central Nigeria, found that weekend delivery, delivery outside vaccination days, public holidays and vaccine stock-outs were barriers to timely vaccination. Only 53.8% of the newborns studied received at-birth vaccination within 24 hours of life.

The finding from Jos is particularly relevant to the present study because it demonstrates that delayed vaccination is not simply a matter of caregiver unwillingness. Danjuma et al. (2020) showed that factors associated with the organization and availability of health services could contribute to delayed vaccination. Thus, assessment of timely completion in Jos North LGA should consider both caregiver-related factors and health-facility factors.

Timely presentation for vaccination has also been examined elsewhere in North-Central Nigeria. Ibraheem et al. (2019) investigated determinants of timely presentation for birth-dose vaccination at an immunization centre and emphasized that timely receipt of immunization is an important prerequisite for early protection of children. This evidence reinforces the need to examine the factors that influence whether caregivers present children for vaccination when the vaccine is due.

The timing of the first vaccination may have implications for subsequent completion. When caregivers initiate vaccination late, they may find it difficult to complete later doses within the recommended schedule. Sadoh and Eregie (2009) found that early commencement of immunization was associated with better completion of the vaccination schedule. Therefore, interventions designed to improve timely completion should not focus only on later doses but should also encourage early initiation of routine vaccination.

Communication and reminder interventions have emerged as potentially useful strategies for improving timely immunization. Oladepo et al. (2021) conducted an intervention study among mothers in rural Nigerian communities and evaluated reminder short message services (SMS) for promoting full and timely completion of routine childhood immunization. Their study demonstrates that mobile-phone reminders can be incorporated into immunization programmes as a practical means of supporting caregivers to remember vaccination appointments.

Similarly, Ekhaguere et al. (2019) evaluated automated phone calls and text-message reminders for childhood immunization in Nigeria through the PRIMM randomized controlled trial. The study examined whether automated reminders could improve childhood immunization attendance and completion. The relevance of such interventions lies in their ability to address forgetfulness and competing demands that may cause caregivers to miss scheduled vaccination appointments.

The acceptability of mobile-phone reminders among Nigerian caregivers has also received empirical attention. Eze et al. (2021), in a systematic review and meta-analysis, examined mobile-phone ownership and willingness among Nigerian mothers and caregivers to receive reminders for routine childhood vaccination appointments. Their findings support the potential use of mobile technologies as part of strategies for improving immunization timeliness in Nigeria.

Cultural and health beliefs may also affect timely use of health services. Caregivers’ perceptions of illness, vaccination and healthcare providers may influence decisions about when and whether to seek immunization services. Kunnuji et al. (2022), using qualitative evidence from Nigeria’s 2019 Vaccine Acceptance Study, showed that health beliefs and perceptions influence timely use of facility-based healthcare for under-five children. This indicates that health interventions should consider the social and cultural environment within which caregivers make decisions.

The issue of timely vaccination is not limited to Nigeria. International research has established that delayed vaccination is an important dimension of immunization performance. Luman et al. (2005) argued that vaccination timeliness should be considered in addition to conventional coverage because children who receive vaccines late may remain susceptible to disease for longer periods. This perspective supports the need for research that measures not merely whether children have received vaccines, but whether they received them at the recommended ages.

Evidence from Nigeria continues to show that timeliness remains an important challenge. Umeokonkwo et al. (2021) examined vaccination timeliness among children attending an immunization clinic in South-East Nigeria and highlighted the need to improve the timing of vaccination among children using routine immunization services. This indicates that delayed vaccination is a problem that cuts across different geographical areas and healthcare settings in Nigeria.

Recent research has further emphasized the concept of age-appropriate immunization. Omale et al. (2025) assessed optimal routine childhood immunization coverage in communities in Ebonyi State using timely or cumulative age-appropriate vaccination as an important outcome. Their work illustrates the growing recognition that immunization programmes should consider whether children receive vaccines at the appropriate age rather than relying exclusively on whether they eventually receive the vaccines. For children under five, timely completion is particularly important because this period encompasses the major part of the routine childhood vaccination schedule. Delays at one stage may result in missed opportunities at subsequent stages. When caregivers fail to return after the first or second dose, the child may remain inadequately protected against diseases that can cause serious illness, disability or death.

Jos North LGA provides an important context for investigating this issue. The area contains a mixture of urban and densely populated communities with caregivers from different educational, occupational and socioeconomic backgrounds. Although primary health centres provide opportunities for routine immunization, the actual ability of caregivers to utilize these services on schedule may differ according to household circumstances and health-service conditions.

The availability of primary healthcare facilities does not necessarily guarantee timely completion of immunization. A facility may exist within a community while caregivers still experience barriers such as transportation costs, inconvenient clinic days, long waiting periods or temporary vaccine unavailability. The findings of Danjuma et al. (2020) in Jos demonstrate that service-related barriers, including vaccine stock-outs and vaccination schedules, can affect timely administration of childhood vaccines.

There is therefore a need to investigate the problem at the level of selected primary health centres in Jos North LGA. Facility-level research can provide information about the experiences of caregivers who actually use routine immunization services. It can identify whether delays are associated primarily with caregiver knowledge and behaviour, socioeconomic conditions, cultural beliefs, accessibility or health-system factors.

The present study is consequently designed to assess the factors influencing timely completion of routine immunization among children under five in selected primary health centres in Jos North LGA, Plateau State. By focusing specifically on timeliness, the study seeks to provide information that goes beyond conventional immunization coverage and may assist health authorities and healthcare workers in developing interventions that ensure children receive protection when they need it most.

1.2 Statement of the Problem

Childhood immunization is a major strategy for preventing vaccine-preventable diseases, but its effectiveness depends on children receiving the recommended vaccines at the appropriate ages and intervals. A child who receives a vaccine after the recommended time may eventually be classified as immunized, yet the child may have remained vulnerable to disease during the period of delay. Consequently, timely completion of routine immunization is an important public health concern.

Evidence from Nigeria demonstrates that delays in childhood vaccination are substantial. Sadoh and Eregie (2009), in a study of 512 Nigerian children attending a clinic-based immunization service, found that approximately 30% presented after four weeks of age for their first immunization, while between 18.9% and 65% experienced delays in receiving various vaccines. Only 44.3% of the children were fully immunized. These findings indicate that the problem involves both delayed initiation and failure to complete the schedule.

The problem is important because delayed vaccination prolongs the period during which children remain susceptible to vaccine-preventable diseases. Timely vaccination is therefore not simply an administrative requirement but a mechanism for ensuring that children obtain protection at the period intended by the vaccination programme. Bailie et al. (2009) similarly emphasized that improving timeliness is necessary to achieve the protective effects of immunization.

In Nigeria, several factors may contribute to delayed completion. Caregivers may lack adequate knowledge of the vaccination schedule, forget appointment dates, have competing domestic or occupational responsibilities or face misconceptions about vaccination. Oladepo et al. (2019) reported poor knowledge of routine childhood immunization among Nigerian rural mothers and identified the potential role of reminder messages in promoting timely completion.

Socioeconomic factors may further complicate the problem. Transportation costs, household financial difficulties, occupation and distance from health facilities can influence whether caregivers are able to attend immunization clinics on scheduled dates. Antai (2009) demonstrated that immunization uptake in Nigeria is influenced by multiple individual and contextual factors, indicating that childhood vaccination cannot be understood solely from the perspective of individual caregiver decisions.

Health-system factors may also cause delays even where caregivers are willing to vaccinate their children. Vaccine stock-outs, inconvenient immunization days, long waiting periods and insufficient health workers can discourage caregivers from returning to health facilities. This concern has particular relevance to Jos. Danjuma et al. (2020), in their study of at-birth vaccination in the highlands of Jos, found that vaccine stock-outs, delivery outside vaccination days, weekend delivery and public holidays were barriers to timely vaccination.

The existence of these challenges means that a caregiver may be knowledgeable and willing to vaccinate but still fail to complete the schedule on time because of circumstances beyond individual intention. Conversely, some caregivers may have access to services but delay vaccination because of inadequate knowledge, forgetfulness or other personal factors. Understanding the relative contribution of these factors is essential for developing effective interventions.

Although studies have examined immunization coverage and timeliness in different parts of Nigeria, there is still a need for localized evidence on the factors influencing timely completion among children under five in selected primary health centres in Jos North LGA. Evidence from other Nigerian regions may not fully explain the circumstances of caregivers in Jos North because communities differ in socioeconomic conditions, healthcare access, service organization and social characteristics.

The problem, therefore, is that despite the availability of routine immunization services, some children under five may not receive their vaccines at the recommended times or may fail to complete the required schedule. Delayed completion can leave children unnecessarily vulnerable to vaccine-preventable diseases and can undermine the effectiveness of routine immunization programmes.

Therefore, this study seeks to assess the factors influencing timely completion of routine immunization among children under five in selected primary health centres in Jos North LGA, Plateau State. The study will examine caregiver knowledge, socioeconomic and demographic characteristics, caregiver-related and cultural factors, as well as health-system and accessibility factors in order to identify the major determinants of timely completion.

1.3 Objectives of the Study

1.3.1 General Objective

The general objective of this study is to assess the factors influencing timely completion of routine immunization among children under five in selected primary health centres in Jos North LGA, Plateau State.

1.3.2 Specific Objectives

The specific objectives are to:

1. assess the level of timely completion of routine immunization among children under five attending selected primary health centres in Jos North LGA;
2. determine the level of caregivers’ knowledge and awareness regarding routine immunization schedules and the importance of timely completion;
3. identify socioeconomic and demographic factors influencing timely completion of routine immunization among children under five;
4. examine caregiver-related and cultural factors influencing timely completion of routine immunization; and

1.4 Research Questions

1. What is the level of timely completion of routine immunization among children under five attending selected primary health centres in Jos North LGA?
2. What is the level of caregivers’ knowledge and awareness regarding routine immunization schedules and timely completion?
3. What socioeconomic and demographic factors influence timely completion of routine immunization among children under five?
4. What caregiver-related and cultural factors influence timely completion of routine immunization?

1.5 Research Hypothesis

H₀: There is no significant relationship between caregivers’ knowledge and timely completion of routine immunization among children under five in selected primary health centres in Jos North LGA, Plateau State.

1.6 Significance of the Study

The findings of this study will be useful to the Plateau State Ministry of Health and primary healthcare authorities because they will provide evidence concerning factors that contribute to delayed or incomplete childhood immunization. Such information may assist programme managers in developing interventions that are specifically suited to the needs of caregivers in Jos North LGA.

The study will also be beneficial to healthcare workers in the selected primary health centres. The findings may help health workers understand the reasons why caregivers miss immunization appointments and may support improvements in health education, appointment scheduling, follow-up and communication with caregivers.

The study will benefit parents and caregivers by increasing awareness of the importance of receiving vaccines at the recommended ages and intervals. It may also encourage caregivers to retain immunization records and attend scheduled appointments promptly.

The study will be relevant to community leaders, religious leaders and community-based organizations because the findings may identify cultural and social factors that influence vaccination decisions. These stakeholders can use the findings to support community mobilization and promote confidence in routine immunization.

The study may also assist non-governmental organizations and development partners working in child health and immunization. Information about barriers such as transportation, vaccine availability, waiting time and appointment reminders may guide the development of targeted interventions.

Finally, the study will contribute to academic literature by providing evidence specifically on timely completion of routine immunization among children under five in Jos North LGA. It may serve as a useful reference for future researchers investigating immunization timeliness and vaccine uptake in Plateau State and other parts of Nigeria.

1.7 Scope of the Study

The study will focus on the factors influencing timely completion of routine immunization among children under five attending selected primary health centres in Jos North LGA, Plateau State.

The study will examine the level of timely completion and factors related to caregiver knowledge and awareness, socioeconomic and demographic characteristics, caregiver-related and cultural influences, health-system conditions and accessibility of immunization services.

Geographically, the study will be restricted to selected primary health centres within Jos North LGA. The study will not cover all health facilities in Plateau State or Nigeria. The findings will therefore primarily reflect the experiences and circumstances of caregivers who utilize the selected facilities.

1.8 Operational Definition of Terms

1. Immunization: The process of protecting an individual against infectious diseases through the administration of vaccines.
2. Routine Immunization: The regular provision of recommended vaccines to children according to the national immunization schedule through fixed, outreach and other approved service delivery platforms.
3. Timely Immunization: Receipt of a recommended vaccine within the age and interval specified by the applicable routine immunization schedule.
4. Timely Completion: Receipt of all required routine childhood vaccines at the recommended ages and intervals.
5. Immunization Completion: Receipt of all vaccine doses required under the recommended routine childhood immunization schedule.
6. Caregiver: A parent, guardian or other adult responsible for the care and health of a child under five years.
7. Vaccine-Preventable Diseases: Diseases that can be prevented through vaccination, including measles, poliomyelitis, tuberculosis, diphtheria, pertussis and tetanus.
8. Primary Health Centre: A healthcare facility providing essential primary healthcare services, including maternal and child health services and routine immunization.
9. Immunization Dropout: Failure of a child who has received an initial vaccine dose to return for one or more subsequent recommended doses.
10. Accessibility: The extent to which caregivers can reach and use immunization services conveniently, considering factors such as distance, transportation, cost and service organization.
11. Health-System Factors: Conditions within the healthcare system that may influence immunization, including vaccine availability, health-worker availability, clinic schedules, waiting time and service organization.
12. Socioeconomic Factors: Individual or household conditions such as education, occupation, income, transportation costs and household responsibilities that may influence timely immunization.

Project – Assessment of Factors Influencing Timely Completion of Routine Immunization Among Children Under Five in Selected Primary Health Centres in Jos North LGA, Plateau State