Background: Rotavirus disease is the leading global cause of severe diarrhea in children under 5 years. We examined the association between different rotavirus vaccines doses and severity of diarrhea.

Methods: A secondary analysis of surveillance of children with acute gastroenteritis (AGE) symptoms during two seasons (January-June) in 2010 and 2011 from three pediatric hospitals in Atlanta, Georgia was conducted. Enrolled children were tested for rotavirus, using EIA (Rotaclone) and vaccination records were collected from the state immunization registry and healthcare providers. Cases were defined as any enrolled child who tested positive for rotavirus. Each enrolled child was assigned a Vesikari score to assess AGE severity.

Results: 63.9% of participants had severe AGE. Cases were more likely to have severe AGE than controls (OR 3.8, 95% CI: 2.2-6.5). Receiving a mixed vaccine regimen had similar protection against severe disease to receiving only RotaTeq® or Rotarix® (Mixed: OR 0.1, 95% CI: 0.02-0.5; RotaTeq®: OR 0.1, 95% CI: 0.02-0.5; Rotarix®: OR 0.1; 95% CI 0.01-0.3). When controlling for vaccine type and demographic covariates, three doses of vaccine offered significant protection against severe disease (OR 0.3, 95% CI: 0.2-0.6).

Conclusions: Receiving a mixed regimen of rotavirus vaccine is effective in preventing severe AGE. Mixed rotavirus vaccine regimens were equally efficacious to receiving a single type of vaccine in preventing severe disease. Three doses of vaccine, regardless of type, were effective in preventing severe disease but one or two doses were not.