Impact of rotavirus vaccination on diarrhea-related hospitalizations in São Paulo State, Brazil.

INTRODUCTION: Following introduction of routine infant rotavirus vaccination, severe diarrhea hospitalization rates declined among children aged <5 years throughout Brazil. Ensuring equity of rotavirus vaccine impact is important in countries that self-finance immunization programs. The objective of this study was to examine rotavirus vaccine impact on diarrhea admission rates among children aged <5 years in Brazil's public health system, according to area-based measures of human development in the state of São Paulo, Brazil.

METHODS: Ecological analysis of public health system hospitalization rates for acute gastroenteritis among children aged <5 years in the state of São Paulo, Brazil, according to five categories of municipal development based on a modified Human Development Index for municipalities. Acute gastroenteritis hospitalization rates among children aged <5 years after national rotavirus vaccine introduction (2008-2011) were compared to rates in pre-vaccine years (2000-2005) to calculate percent decline in rates (1-rate ratio) and 95% confidence intervals (CI) for each municipal development category. Direct hospitalization costs during the two periods were compared.

RESULTS: Annual rates declined by 40% (95% CI, 39-42%) from 631 diarrhea hospitalizations per 100,000 person years pre-rotavirus vaccination to 377 per 100,000 post-vaccination among children aged <5 years and 50% (95% CI, 48-52%) from 1009 to 505 per 100,000 among infants. Highest rates were observed in least developed municipalities. Significant declines of 26-52% among children <5 years and 41-63% among infants were observed in all categories of municipal development. Lower diarrhea hospitalization rates resulted in annual savings of approximately 2 million USD for the state of São Paulo. Savings in direct hospitalization costs benefitted municipalities in all five categories.

CONCLUSION: The introduction of rotavirus vaccination was associated with substantial reductions of diarrhea-related admissions at all levels of municipal development in São Paulo State, Brazil.