Incidence of rotavirus and all-cause diarrhea in northeast Brazil following the introduction of a national vaccination program

Abstract

Background & aims: Rotavirus vaccines were introduced in Brazil in 2006; we evaluated their effects in the state of Sergipe, Brazil.

Methods: We performed a cross-sectional survey of children with diarrhea attending emergency services in Aracaju, Brazil, between October 2006 and April 2008 and a cluster sampling survey to assess vaccination coverage. Vaccine efficacy was assessed using the screening method. Diarrhea consultation and hospitalization data (2003-2007) were obtained from state and national surveillance systems.

Results: Rotavirus was detected in 59 of 534 stool samples (11%) from children attending emergency services. The number of rotavirus-positive samples decreased from 18 of 74 (24%) in 2006 to 31 of 321 (9.5%) in 2007 and 10 of 136 (7.4%) in 2008 (P < .01). Diarrhea severity was greater in children with rotavirus (P < .01) but decreased over time (P < .001). Of the rotaviruses detected, 56 of 59 (95%) were P[4]G2 genotype, 1 was P[4]G-non-typeable (NT), 1 was P[NT]G2, and 1 was P[NT]GNT. Diarrhea consultations decreased from 3020 in 2004 to 604 in 2007; reductions were greatest among children under 5 years old. Diarrhea hospitalizations decreased from 2121 in 2003 to 1176 in 2007. Vaccine coverage was 90.3%. Vaccines were highly effective against the strain P[8]G1; efficacy against P[4]G2 genotype was 89% (95% confidence interval: 0.87-0.92) in Aracaju and 95% in Sergipe.

Conclusions: Since vaccines were introduced in 2006, there has been an overall reduction in diarrhea consultations and hospitalizations in northeast Brazil, with the greatest reductions in young children. This might have resulted from vaccination and improved sanitation. Although a single rotavirus genotype (P[4]G2) was recovered, vaccine efficacy was high against this genotype.