Factors Associated with Vaccine Uptake: A Study on Rabies Post-Exposure Prophylaxis in The Philippines

Introduction: Rabies, a fatal vaccine-preventable disease, is endemic in the Philippines. The national rabies program aims to offer free vaccination using a 3-dose schedule when WHO-prequalified vaccine is available and 4 doses when not. The PhD objectives were to quantify vaccine adherence, explore immunisation attitudes, assess factors associated with uptake, and understand facilitators and barriers to completion. Methods: Four studies were conducted at San Lazaro Hospital (SLH)’s animal bite treatment centre (ABTC), Manila. A formative observation study including in-depth interviews with providers contextualised the ABTC. A retrospective database analysis and a prospective mixed-method cohort study assessed vaccine completion and factors associated with adherence. The final study surveyed rabies-exposed individuals to investigate failure to initiate vaccination. Results: Over 300,000 patients accessed the SLH ABTC between 2016 and 2021, 27% of whom completed vaccination. The prospective study of 506 participants reported 86% vaccine completion. Females and participants aged 60+ had higher odds of adherence. The main barriers to vaccine uptake were a lack of time, the inability to access ABTCs when travelling outside Manila, and forgotten schedules. Major facilitators to vaccine uptake were high confidence in rabies vaccine and the influence of individuals’ social networks. Highlights: This PhD reported three novel observations: 1) clinics and healthcare providers can be deterrents to rabies vaccine completion, 2) individuals’ social networks influence rabies vaccine uptake and can be leveraged to improve vaccine adherence, 3) travelling outside Manila is a frequently reported barrier to vaccine completion. Conclusion: This PhD underscored the need to improve vaccine uptake. While vaccines may be provided free, costs such as travel, and the loss of productive time and wages, are barriers to vaccine uptake. It is essential to evaluate access to ABTCs across the country and institute the permanent use of WHO-prequalified vaccines to increase vaccine completion.