Behavioural and social drivers of routine childhood immunization in selected low coverage areas in the Philippines.

Background: Routine childhood vaccination coverage under the National Immunization Program of the Philippines is well below the target of 95% with a high number of zero-dose children. Declining immunization rates led to outbreaks of vaccine-preventable diseases such as measles, polio, and pertussis. This study aimed to identify the factors affecting childhood vaccine uptake by exploring the perspectives of community members, program managers, and coordinators.

Methods: Three regions with low vaccine coverage in the Philippines were selected as study sites. We conducted focus groups with adult caregivers of vaccinated and unvaccinated children aged 0-11 years recruited by barangay (community) health workers. Key informant interviews were also conducted with immunization program managers and coordinators from different administrative levels. Focus group and interview guides were informed by the World Health Organization's Behavioural and Social Drivers (BeSD) of Vaccination framework. Transcripts were analysed by themes and deductive axial coding was used to categorize themes into BeSD domains and socioecological levels.

Results: Twelve focus groups (n = 143) and 57 key informant interviews were done. Various behavioural and social drivers of vaccination present at different levels of the socioecological model affect vaccine decisions both positively and negatively. Under the 'Thinking and feeling' domain of the BeSD, at the intrapersonal level, the perception of benefits and negative side effects of routine vaccines were clear drivers of vaccination. In the 'Social processes' domain, factors at multiple socioecological levels such as the influence of family, barangay health workers, and community leaders were identified. Practical issues such as the availability of vaccines and accessibility of vaccination sites remain a barrier to vaccination.

Conclusions: Availability of routine vaccines and accessibility to vaccination sites are major challenges in the Philippines. Acceptability of routine vaccines continue to be affected by previous controversies around the Dengue vaccine and the recent COVID-19 pandemic. Findings suggest that enhancing advocacy for immunization through continuing communication training for health care workers on health promotion and education regarding vaccination may contribute to increased vaccine uptake. Integration of immunization with other population-based health programs could be explored.