Sustained Effectiveness of Rotavirus Vaccine Against Very Severe Rotavirus Disease Through the Second Year of Life, Bolivia 2013-2014

Background. In Bolivia, monovalent rotavirus vaccine was introduced in 2008 and a previous evaluation reported a vaccine effectiveness (VE) of 77% with 2 doses of vaccine in children aged < 3 years. This evaluation sought to determine if rotavirus vaccine provided protection through the second year of life against circulating genotypes. Methods.aEuro integral A case-control study was performed in 5 hospitals from April 2013 to March 2014. Among enrolled participants who met study criteria and had rotavirus stool testing performed and vaccine status confirmed, we calculated VE using a logistic regression model. Subgroup analyses were performed among children aged < 1 year and those aged a parts per thousand yen1 year, among children with severe diarrhea (Vesikari score a parts per thousand yen11) and very severe diarrhea (Vesikari score a parts per thousand yen15), and among G and P strains with at least 40 specimens. Results.aEuro integral A total of 776 children were enrolled. For children < 1 year and a parts per thousand yen1 year of age with severe diarrhea, VE for 2 doses was 75% (95% confidence interval [CI], 46%-88%) and 53% (95% CI, 9%-76%), respectively. For children < 1 year and a parts per thousand yen1 year of age with very severe diarrhea, VE for 2 doses was 80% (95% CI, 44%-93%) and 74% (95% CI, 35%-90%), respectively. Genotype-specific analysis demonstrated similar VE for the 4 most common G and P types (G3, G9, P[6] and P[8]). Conclusions.aEuro integral A monovalent rotavirus vaccine remains effective against a broad range of circulating strains as part of a routine immunization program > 5 years after its introduction in Bolivia. Although VE appears to wane in children aged a parts per thousand yen1 year, it still provides significant protection, and does not wane against severe disease.