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Published on: January 28, 2019
Enteropathogen Changes After Rotavirus Vaccine Scale-up
Sarah-Blythe Ballard1,2,3, David Requena1, Holger Mayta4,5
1Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.
Insights
Norovirus genogroup II (GII) and sapovirus are now leading causes of pediatric gastroenteritis after rotavirus vaccine implementation. Both pathogens significantly contribute to severe disease, suggesting a need for multivalent vaccines.
Area of Science:
- Pediatric infectious diseases
- Vaccinology
- Microbiology
Background:
- Rotavirus vaccine implementation has altered the landscape of pediatric gastroenteritis pathogens.
- Understanding these shifts is crucial for effective diarrhea burden reduction strategies.
Purpose of the Study:
- To assess the post-vaccine enteropathogen landscape in pediatric gastroenteritis.
- To determine the burden and severity of specific pathogens causing diarrhea in children.
Main Methods:
- A case-control study involving 1788 children under 5 years old in Peru.
- Stool testing for viruses, bacteria, and parasites, with coinfection-adjusted attributable fractions calculated.
- Gastroenteritis severity assessed using Clark and Vesikari scales.
Main Results:
- Norovirus GII (29.1%), rotavirus (8.9%), and sapovirus (6.3%) were significantly associated with gastroenteritis.
- Norovirus GII and cases in 6-12 month olds showed higher severity scores.
- Partially heterotypic rotavirus strain G12P[8] was the most frequent rotavirus type.
Conclusions:
- Norovirus GII and sapovirus are major contributors to pediatric gastroenteritis after rotavirus vaccination.
- These findings highlight the importance of considering sapovirus in diarrhea burden reduction.
- Multivalent vaccines targeting multiple caliciviruses may be beneficial in similar settings.
Objectives:
To inform next steps in pediatric diarrhea burden reduction by understanding the shifting enteropathogen landscape after rotavirus vaccine implementation.
Methods:
We conducted a case-control study of 1788 medically attended children younger than 5 years, with and without gastroenteritis, after universal rotavirus vaccine implementation in Peru. We tested case and control stools for 5 viruses, 19 bacteria, and parasites; calculated coinfection-adjusted attributable fractions (AFs) to determine pathogen-specific burdens; and evaluated pathogen-specific gastroenteritis severity using Clark and Vesikari scales.
Results:
Six pathogens were independently positively associated with gastroenteritis: norovirus genogroup II (GII) (AF 29.1, 95% confidence interval [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), astrovirus (AF 2.8, 95% CI: 0.0-4.0); enterotoxigenic Escherichia coli heat stable and/or heat labile and heat stable (AF 2.4, 95% CI: 0.6-3.1), and Shigella spp. (AF 2.0, 95% CI: 0.4-2.2). Among typeable rotavirus cases, we most frequently identified partially heterotypic strain G12P[8] (54 of 81, 67%). Mean severity was significantly higher for norovirus GII-positive cases relative to norovirus GII-negative cases (Vesikari [12.7 vs 11.8; P < .001] and Clark [11.7 vs 11.4; P = .016]), and cases in the 6- to 12-month age range relative to cases in other age groups (Vesikari [12.7 vs 12.0; P = .0002] and Clark [12.0 vs 11.4; P = .0016]).
Conclusions:
Norovirus is well recognized as the leading cause of pediatric gastroenteritis in settings with universal rotavirus vaccination. However, sapovirus is often overlooked. Both norovirus and sapovirus contribute significantly to the severe pediatric disease burden in this setting. Decision-makers should consider multivalent vaccine acquisition strategies to target multiple caliciviruses in similar countries after successful rotavirus vaccine implementation.
