Background Immunization is a vital public health intervention for preventing childhood diseases and reducing mortality rates. Despite global efforts, Nigeria, particularly Bayelsa State, continues to experience suboptimal immunization coverage, often exacerbated by logistical challenges, caregiver misconceptions, and cultural beliefs. The GAVI Alliance has aimed to enhance vaccine availability and community engagement in immunization programs, yet the impact on local coverage and card retention remains under-researched.

Objective This study aimed to assess the current immunization coverage, card retention, and barriers to vaccination among children aged 0-59 months in Bayelsa State, following GAVI support.

Methods A descriptive cross-sectional survey was conducted, utilizing a multistage sampling approach to collect data from 420 caregivers of eligible children through structured interviews and immunization card verification. Data were analysed using descriptive and inferential statistics, including Chi-square tests and logistic regression.

Results The findings revealed an overall immunization coverage of 95.5%, a significant increase from the baseline of 61.12%. BCG and OPV vaccines demonstrated high coverage rates (93.6% and 94.3%, respectively), while the measles and yellow fever vaccines showed lower coverage (56.0% and 54.5%). Notably, caregiver concerns about vaccine safety and potential side effects were prevalent, influencing non-compliance, with 34.6% citing forgetfulness as a reason for missed vaccinations. Moreover, educational level and distance to health facilities were significant factors affecting immunization card retention and compliance.

Conclusion The study underscores the positive impact of GAVI-supported initiatives on immunization coverage in Bayelsa State. However, persistent gaps in specific vaccine uptake and caregiver perceptions necessitate targeted educational interventions and improved access to healthcare services to sustain high immunization rates and protect children from vaccine-preventable diseases.

The authors have declared no competing interest.

https://docs.google.com/forms/d/1-gt04kifXvrLUNtoI7ci6rvh_fpyyVyceRr84Tm9FHQ/edit

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol was reviewed and approved by the Ethics Review Committee of the Bayelsa State Primary Health Care Board (PHCB/AD/171/p.18, 10th July 2025).

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The data collected for this study on childhood vaccine immunization coverage in Bayelsa State were gathered using Google Forms, a widely used online survey tool. The structured questionnaire was designed to capture various aspects, including caregiver demographics, immunization status, card retention, and perceptions regarding vaccination. Upon completion of the data collection phase, the responses were automatically compiled into a Google Sheets format, which was subsequently exported into Microsoft Excel for further analysis. The dataset is available upon reasonable request. Interested parties can contact the corresponding author via email to obtain access to the anonymized dataset. The data will be shared in accordance with ethical considerations and the privacy of the participants, ensuring that no personally identifiable information is disclosed.

https://docs.google.com/forms/d/1-gt04kifXvrLUNtoI7ci6rvh_fpyyVyceRr84Tm9FHQ/edit