BACKGROUND:
Rotavirus (RV) is the leading cause of dehydrating gastroenteritis (AGE) in infants worldwide. We developed a rotavirus vaccine (RotaTeq™) containing five reassortants (bovine rotavirus strain WC3 with surface proteins of either human serotype G1, G2, G3, G4, or P1).

OBJECTIVE:
We report final results of a double and in-house blinded, randomized, placebo-controlled study that evaluated RotaTeq™ at expiry (end of shelf-life) potency in the final formulation intended for clinic administration.

METHOD:
During 2002-2004, 1310 healthy infants ~6-12 weeks old from the U.S. and Finland were enrolled to receive 3 doses of oral vaccine or placebo ~4-10 weeks apart. Infants were randomized to RotaTeq™ at ~1.1 x 10^7 Infectious Units/Dose or placebo and were followed for AGE through one RV season.

RESULT:
Efficacy [95% CI] against any severity of naturally occurring rotavirus gastroenteritis caused by the human G-serotypes included in the vaccine was 72.5% [50.6%, 85.6%], based on 69 cases (66 were G1, 3 were G3). Efficacy for severe RV AGE was 100% (score >16 on a 24-point clinical scoring system). A 3-fold rise in G1 serum neutralizing antibody titer and anti-rotavirus IgA was observed in ~57% (38/67) and ~96% (64/67) of vaccinees, respectively. There was no excess vomiting, diarrhea, or irritability among vaccinees during the 7-day period after any dose; there was statistical increase in elevated temperature (>100.5oF, rectal equivalent) among vaccine (13.4%) compared to placebo (8.8%) recipients during the 7-day period Postdose 1. This was not observed Postdose 2 or 3. Vaccine strain shedding was detected in one AGE sample from one vaccinee 3 days Postdose 1. There were no cases of intussusception. Formal evaluation of intussusception and vaccination is occurring in another large-scale Phase III study.

CONCLUSION:
RotaTeq™ at expiry potency is generally well-tolerated and efficacious against RV AGE.

LEARNING OBJECTIVES:
Understand efficacy and safety profile of RotaTeq™.