Undergraduate thesis.

Immunization is one of the most effective public health strategies for protecting children against vaccine-preventable diseases. Despite the availability of free vaccines through the National Immunization Program (NIP), many Filipino children remain partially unvaccinated, particularly in underserved areas. This study explores the underlying reasons behind delayed or incomplete immunization among children, otherwise known as defaulters. The primary objective of this research is to identify and understand the challenges experienced by parents and guardians in adhering to the recommended immunization schedule for their children. Through a qualitative approach, interviews were conducted with elected participants who are parents or guardians of children aged 0-23 months with incomplete immunization residing in Bernabe or Lorenzana. The study revealed several recurring themes contributing to immunization delays. Some common reasons cited is the lack of finances for transportation to the health center, especially for families with unstable income, and parental busyness where caregivers expressed that despite knowing the importance of vaccines, daily priorities prevented them from bringing the child to scheduled appointments. Furthermore, social media emerged as a source of misinformation and fear, discouraging some parents or guardians from completing the immunization process. Finally, concerns about side effects, particularly fever, were mentioned frequently and often led to missed or skipped follow-up doses. These findings suggest that barriers to immunization are rooted not only in logistical and financial issues but also in social and informational dynamics. Addressing these challenges requires tailored community-based interventions, health education campaigns, and support systems to empower parents and guardians, and ensure that children receive complete and timely vaccinations.