Risk of reintroduction of vaccine preventable diseases in the state of São Paulo, Brazil

Abstract

OBJECTIVE: To analyze the risk classification of transmission of vaccine-preventable diseases in the municipalities of the state of São Paulo (SP) and to assess the influence of population size on the risk of transmission of vaccine-preventable diseases (RTDI) before and after the implementation of Microplanning for High-Quality Vaccination Activities. METHODS: This is an epidemiological study with an ecological design, conducted using secondary data on vaccination coverage for nine immunobiologicals recommended in the immunization schedule for children under two years of age. It also examines dropout rates for multi-dose vaccines within the same age group in the state of São Paulo, covering the years 2022 and 2023. Following the calculation of all indicators, municipalities were classified according to their risk of transmission for vaccine-preventable diseases. RESULTS: Analyses of vaccination coverage indicators, dropout rates, homogeneity of vaccination coverage among vaccines for children under two years of age, and the RTDI indicator for children aged one year or younger revealed that, in 2022, the human rotavirus vaccine had the highest proportion of municipalities reaching the coverage target (46%), followed by the meningococcal vaccine (39%). In 2023, the human rotavirus vaccine maintained the highest proportion of municipalities reaching the target (68%), followed by the pneumococcal vaccine (57%). Regarding the RTDI, in large municipalities, high risk fell from 100% to 91.2%, while in medium-sized municipalities there was a reduction from 90.8% to 66.7%, and in small municipalities, from 68.3% to 56%. CONCLUSION: Challenges remain within the state regarding the RTDI classification for vaccination, particularly in medium-sized and large municipalities. The use of immunization indicators at the municipal level can be highly effective for proposing health interventions aimed at increasing vaccination coverage.