Rotavirus Vaccine Effectiveness Against Severe Acute Gastroenteritis: 2009-2022

Background: Rotavirus was the leading cause of acute gastroenteritis among US children until vaccine introduction in 2006, after which, substantial declines in severe rotavirus disease occurred. We evaluated rotavirus vaccine effectiveness (VE) over 13 years (2009-2022).

Methods: We analyzed data from the New Vaccine Surveillance Network using a test-negative case-control design to estimate rotavirus VE against laboratory-confirmed rotavirus infections among children seeking care for acute gastroenteritis (≥3 diarrhea or ≥1 vomiting episodes within 24 hours) in the emergency department (ED) or hospital. Case-patients and control-patients were children whose stool specimens tested rotavirus positive or negative, respectively, by enzyme immunoassay or polymerase chain reaction assays. VE was calculated as (1-adjusted odds ratio)×100%. Adjusted odds ratios were calculated by multivariable unconditional logistic regression.

Results: Among 16 188 enrolled children age 8 to 59 months, 1720 (11%) tested positive for rotavirus. Case-patients were less often vaccinated against rotavirus than control-patients (62% versus 88%). VE for receiving ≥1 dose against rotavirus-associated ED visits or hospitalization was 78% (95% confidence interval [CI] 75%-80%). Stratifying by a modified Vesikari Severity Score, VE was 59% (95% CI 49%-67%), 80% (95% CI 77%-83%), and 94% (95% CI 90%-97%) against mild, moderately severe, and very severe disease, respectively. Rotavirus vaccines conferred protection against common circulating genotypes (G1P[8], G2P[4], G3P[8], G9P[8], and G12[P8]). VE was higher in children <3 years (73% to 88%); protection decreased as age increased.

Conclusions: Rotavirus vaccines remain highly effective in preventing ED visits and hospitalizations in US children.