Effectiveness of monovalent rotavirus vaccine in Bolivia: case-control study

Abstract

Objective To evaluate the effectiveness of two doses of a monovalent rotavirus vaccine (RV1) against hospital admission for rotavirus in Bolivia.Design Case-control study.Setting Six hospitals in Bolivia, between March 2010 and June 2011.Participants 400 hospital admissions for rotavirus, 1200 non-diarrhea hospital controls, and 718 rotavirus negative hospital controls. Main outcome measuresOdds of antecedent vaccination between case patients and controls; effectiveness of vaccination ((1-adjusted odds ratio)×100), adjusted for age and other confounders; and stratified effectiveness by dose, disease severity, age group, and serotype. ResultsIn comparison with non-diarrhea controls, case patients were more likely to be male and attend day care but less likely to have chronic underlying illness, higher level maternal education, and telephones and computers in their home. Rotavirus negative controls were somewhat more similar to case patients but also were more likely to be male and attend day care and less likely to have higher level maternal education and computers in their homes. The adjusted effectiveness of RV1 against hospital admission for rotavirus was 69% (95% confidence interval 54% to 79%) with rotavirus negative controls and 77% (65% to 84%) with non-diarrhea controls. The effectiveness of one dose of RV1 was 36% and 56%, respectively. With both control groups, protection was sustained through two years of life, with similar efficacy against hospital admission among children under 1 year (64% and 77%) and over 1 year of age (72% and 76%). RV1 provided significant protection against diverse serotypes, partially and fully heterotypic to the G1P[8] vaccine. Effectiveness using the two control groups was 80% and 85% against G9P[8], 74% and 93%% against G3P[8], 59% and 69% against G2P [4], and 80% and 87% against G9P[6] strains. ConclusionThe monovalent rotavirus vaccine conferred high protection against hospital admission for diarrhea due to rotavirus in Bolivian children. Protection was sustained through two years of life against diverse serotypes different from the vaccine strain.

Burden of Norovirus and Rotavirus in Children After Rotavirus Vaccine Introduction, Cochabamba, Bolivia

“…The literature describing the burden of rotavirus in Bolivia has demonstrated the effectiveness of rotavirus vaccine in the region. 5,6,14,16,17 Seven years before vaccine introduction at this study site, rotavirus was detected by PCR in 24% of 317 children aged < 5 years hospitalized with AGE. 17 Rotavirus prevalence was 36% when children < 2 years were analyzed separately, nearly double the prevalence described here (19%).…”

“…Higher relative norovirus prevalence in this age group may be because of greater reductions in rotavirus infections in children aged < 12 months after vaccine introduction; however, rotavirus vaccine in Bolivia has demonstrated similar efficacy in both children under and above 12 months. 12,14 Asymptomatic norovirus infections were very common. Children infected with norovirus are known to shed the virus for several weeks to months after both symptomatic and asymptomatic infections.…”

“…13 Rotavirus vaccination uptake is high in Bolivia (> 85%, two-dose coverage), and the vaccine has demonstrated high efficacy against rotavirus infection despite fears that the vaccine may be less effective in resource poor settings. 14,15 Reductions in hospitalization due to all-cause AGE have been described in multiple Latin American countries with reductions as high as 18% after vaccine introduction. 6 Reductions in rotavirus prevalence after vaccine introduction has been previously demonstrated by Bolivian investigators.…”

Epidemiological and Economic Impact of Monovalent and Pentavalent Rotavirus Vaccines in Low and Middle Income Countries

“…9 Besides the need to assess different rotavirus vaccine choices, several studies have improved what is known about diarrheal diseases and rotavirus vaccine efficacy and effectiveness in different settings around the world. 6,[10][11][12][13][14][15][16][17] Despite the effectiveness, safety, cost-effectiveness and World Health Organization (WHO) recommendations to introduce RV1 or RV5, 18,19 most countries have not yet introduced the vaccine, most of these in Africa and Asia. As of August 5, 2014, 68 countries have introduced RV1/RV5 in their Expanded Programs on Immunizations (EPI) schedules.…”

Probiotics, antibiotics and the immune responses to vaccines

“…Several candidate rotavirus vaccines (RIT4237, WC3, RRV and RRV-TV) had lower or no measureable efficacy in clinical trials in South America and Africa compared with Europe and North America [1]. More recent studies with new licenced vaccines, Rotarix and Rotateq, have shown lower efficacy and effectiveness in developing countries in Asia, Africa and Latin America [2][3][4][5][6]. The OPV has also faced challenges in the developing world.…”