Search

We sought datasets with granular age distributions of rotavirus-positive disease presentations among children <5 years of age, before the introduction of rotavirus vaccines. We identified 117 datasets and fit parametric age distributions to each country dataset and mortality stratum. We calculated the median age and the cumulative proportion of rotavirus gastroenteritis events expected to occur at ages between birth and 5.0 years. The median age of rotavirus-positive hospital admissions was 38 weeks (interquartile range [IQR], 25-58 weeks) in countries with very high child mortality and 65 weeks (IQR, 40-107 weeks) in countries with very low or low child mortality. In countries with very high child mortality, 69% of rotavirus-positive admissions in children <5 years of age were in the first year of life, with 3% by 10 weeks, 8% by 15 weeks, and 27% by 26 weeks. This information is critical for assessing the potential benefits of alternative rotavirus vaccination schedules in different countries and for monitoring program impact.

BACKGROUND: The etiology of acute watery diarrhea remains poorly characterized, particularly after rotavirus vaccine introduction. METHODS: We performed quantitative polymerase chain reaction for multiple enteropathogens on 878 acute watery diarrheal stools sampled from 14643 episodes captured by surveillance of children <5 years of age during 2013-2014 from 16 countries. We used previously developed models of the association between pathogen quantity and diarrhea to calculate pathogen-specific weighted attributable fractions (AFs). RESULTS: Rotavirus remained the leading etiology (overall weighted AF, 40.3% [95% confidence interval {CI}, 37.6%-44.3%]), though the AF was substantially lower in the Americas (AF, 12.2 [95% CI, 8.9-15.6]), based on samples from a country with universal rotavirus vaccination. Norovirus GII (AF, 6.2 [95% CI, 2.8-9.2]), Cryptosporidium (AF, 5.8 [95% CI, 4.0-7.6]), Shigella (AF, 4.7 [95% CI, 2.8-6.9]), heat-stable enterotoxin-producing Escherichia coli (ST-ETEC) (AF, 4.2 [95% CI, 2.0-6.1]), and adenovirus 40/41 (AF, 4.2 [95% CI, 2.9-5.5]) were also important. In the Africa Region, the rotavirus AF declined from 54.8% (95% CI, 48.3%-61.5%) in rotavirus vaccine age-ineligible children to 20.0% (95% CI, 12.4%-30.4%) in age-eligible children. CONCLUSIONS: Rotavirus remained the leading etiology of acute watery diarrhea despite a clear impact of rotavirus vaccine introduction. Norovirus GII, Cryptosporidium, Shigella, ST-ETEC, and adenovirus 40/41 were also important. Prospective surveillance can help identify priorities for further reducing the burden of diarrhea.

Worldwide, noroviruses are a leading cause of gastroenteritis. They can be transmitted from person to person directly or indirectly through contaminated food, water, or environments. To estimate the proportion of foodborne infections caused by noroviruses on a global scale, we used norovirus transmission and genotyping information from multiple international outbreak surveillance systems (Noronet, CaliciNet, EpiSurv) and from a systematic review of peer-reviewed literature. The proportion of outbreaks caused by food was determined by genotype and/or genogroup. Analysis resulted in the following final global profiles: foodborne transmission is attributed to 10% (range 9%-11%) of all genotype GII.4 outbreaks, 27% (25%-30%) of outbreaks caused by all other single genotypes, and 37% (24%-52%) of outbreaks caused by mixtures of GII.4 and other noroviruses. When these profiles are applied to global outbreak surveillance data, results indicate that approximate to 14% of all norovirus outbreaks are attributed to food.