Effect of Rotavirus Immunization on Childhood Diarrhea in Nicaragua, Research Plan for International Research Scientist Development Award (K01) Fogarty International Center
The impact of universal rotavirus immunization on childhood diarrhea in Nicaragua is unknown. A clear understanding of the magnitude of the effect of UIRI is important information for Nicaragua and other developing world countries who are considering adding rotavirus vaccines to their current vaccine armamentarium. Although preliminary research is measuring the impact of rotavirus immunization in the hospital setting, virtually nothing is known about the effect of UIRI at the primary care or community level. Also, it is not known if genotype shift of the virus is occurring, which could limit the future effectiveness of rotavirus immunization and would inform needed improvements in the vaccine. Finally, we do not know if UIRI is inducing herd immunity. The purpose of this study is to determine the effect of UIRI on diarrheal disease in Nicaragua at the primary care and community levels. Our specific aims are to: 1. Determine the effectiveness of the rotavirus vaccine in primary care clinical practice, using a case-control study. Hypothesis: We expect that UIRI with Rotateq® will have a vaccine effectiveness of about 75% in reducing rotavirus infections that present to primary care centers. 2. Determine the effect of UIRI on diarrhea incidence at the community level, using an existing population-based surveillance system. We will compare incidences prior to UIRI to incidences following UIRI separately for children who did and did not receive the immunization. Hypothesis: Prior hospital-based studies would lead us to expect a one-third reduction in diarrhea incidence among immunized children at the community level. We expect this reduction to be most pronounced during the dry season, when the incidence of rotavirus infection is higher. We expect to find a modest, but measurable reduction in incidence among unimmunized children. 3. Explore if circulating genotypes of the virus have changed following UIRI. We will compare the distribution of rotavirus genotypes prior to UIRI with the distribution following UIRI. Hypothesis: We expect to find a higher percentage of genotypes not covered by the Rotateq® vaccine among immunized children who subsequently develop rotavirus infection. Our analysis of the overall distribution of genotypes following UIRI is exploratory in nature.Master of Public Healt
