Effectiveness of childhood varicella vaccine. Casanare, Colombia

Abstract

Background: Varicella is an immunopreventable disease that mainly affects children. Vaccination is the most cost-effective measure to prevent the disease and its possible complications. Aim: To estimate the effectiveness of the first dose of varicella vaccine in infant population born after 2014. Methods: Retrospective observational study conducted from the review of official health sources for the period 2014- 2021. Vaccine effectiveness was estimated using the screening method, comparing the proportion of vaccinated cases (PCV) with the proportion of the vaccinated child population (PPV). Kaplan-Meier curves were used for survival analysis. Results: Vaccine effectiveness (VE) was 63.5% (95%CI 53.9-70.8). In the vaccinated group of children, the median survival to disease manifestation was 162 days (95% CI, 146-176), while in the unvaccinated it was 47 days (95%CI, 32-116). Conclusions: These findings support the effectiveness of the first dose of varicella vaccine under real-world conditions, demonstrating its positive impact on reducing the spread of the virus and addressing key issues such as the need for booster doses.