Reasons for delayed pentavalent vaccinations among children aged 12-23 months in Kampala, Uganda

Introduction: Delayed vaccination significantly reduces the proportion of individuals with full immunity against targeted diseases, undermining the goal of achieving herd immunity. Delay also increases the likelihood of missing subsequent doses and dropping out of the schedule. This study examined the reasons for delayed pentavalent vaccinations among children aged 12-23 months in Kampala, Uganda. Methods: Selection of 653 study participants into this household survey was done using a three-stage sampling technique. Delayed vaccination was considered if vaccination occurred outside the following time ranges: Pentavalent 1 (4 weeks-2 months), Pentavalent 2 (8 weeks-4 months), and Pentavalent 3(12 weeks-6 months). Data on vaccination status; socio-demographic and attitudinal factors were obtained using an interviewer administered structured questionnaire. Modified Poisson regression analysis was done in STATA version 14.0. Results: Overall, 97.4% (636/653) of the children had ever been vaccinated. About 30.7% (95% CI 26.3-33.3) of these had delayed receipt of at least one dose of the pentavalent vaccines. The prevalence of delayed vaccinations was lower if the caretaker had attained secondary school education (APR= 0.52, 95% CI 0.38-0.70); believed in the effectiveness of vaccines (APR= 0.74, 95% CI 0.55-0.99), perceived a higher risk of their child contracting a vaccine-preventable disease (APR= 0.74, 95% CI 0.58-0.94), and if they had trust in the information provided by health workers (APR=0.61, 95% CI 0.43-0.88). The prevalence of delay was higher if the caretaker was not the biological parent of the child (APR=1.82, 95% CI 1.11-3.00) or if they had negative emotions resulting from previous vaccination experiences (APR=1.48, 95% CI 1.15-1.90) Conclusions: It is imperative to strengthen initiatives to improve knowledge and understanding of the benefits of age-appropriate vaccination for children among primary caretakers in this setting. This study describes the individuals that could be targeted for such interventions