Etiology of Gastroenteritis in Two Populations in Peru: Medically-attended Young Children and a Peruvian Military Cohort
Embargo until
2021-08-01
Date
2017-07-28
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Johns Hopkins University
Abstract
Globally, norovirus is the most common cause of acute sporadic gastroenteritis in adults and the second leading cause of severe diarrhea in children, after rotavirus. Vaccine development against norovirus is currently underway. Successful vaccination strategies against norovirus will require understanding the burden of disease and relevant genotypes in target populations. However, due to the cost associated with molecular diagnostics, few data are available from populations living in low- and middle-income countries (LMIC). We conducted epidemiological studies in two populations. (1) To evaluate the burden of disease, predominate genotypes, and associated symptoms among adults living in an LMIC setting, we conducted a nested case-control study within a Peruvian military cohort from 2004 through 2011. We then used the epidemiological data from this study to evaluate the cost-effectiveness of a potential vaccine against norovirus in this adult population. (2) We then conducted a case-control study in the national children’s hospital in Peru following the universal implementation of a vaccine against rotavirus in order to determine the a) pathogen-specific attributable risk among children with medically-attended gastroenteritis; b) relationship between pediatric infection with specific pathogens and gastroenteritis severity; and c) genetic diversity of circulating norovirus, sapovirus, and rotavirus. We found that, after Shigella, norovirus was the leading cause of diarrhea in the adult Peruvian military population, contributing to a disease attributable fraction (AF) of 6.4%. Relative to implementation in the United States, we calculated Shigella vaccine implementation to be significantly more cost-effective for the Peruvian military (CERDDL=$350 versus $1275), with norovirus vaccine implementation being moderately more cost effective (CERDDL=$926 versus $1344). In the pediatric hospital population, we found that the following six pathogens were independently positively associated with gastroenteritis: norovirus GII (AF 29.1, 95% CI: 28.0-32.3); rotavirus (AF 8.9, 95% CI: 6.8-9.7); sapovirus (AF 6.3, 95% CI: 4.3-7.4); ETEC St=/Lt+St+ (AF 2.4, 95% CI: 0.6-3.1); Shigella (AF 2.0, 95% CI: 0.4-2.2); and astrovirus (AF 2.8, 95% CI: 0.0-4.0). Caliciviruses are an important cause of diarrhea among children with medically-attended diarrhea in Peru, as well as adults in special populations, such as the military. Control strategies should consider multivalent vaccines that target these pathogens.
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Keywords
Peru, gastroenteritis, norovirus, sapovirus, vaccine cost-effectiveness, military