KEYWORDS:
Rotavirus vaccine

BACKGROUND:
Rotavirus (RV) is the leading cause of dehydrating gastroenteritis (AGE) world-wide. A licensed tetravalent rhesus-based reassortant rotavirus vaccine was withdrawn because of its association with intussusception. RV vaccines with a favorable safety profile remain a public health priority; human-bovine reassortant RV vaccines represent an alternative to rhesus reassortants.

OBJECTIVE(S):
We report final results of a randomized, double-blind, placebo-controlled study of live attenuated QRV containing human-bovine (WC3) reassortant RV serotypes G1, G2, G3, and P1a with a dose of 10⁷ pfu/ml for each reassortant.

METHOD(S):
During 1993-94, at 10 U.S. study sites, 439 healthy infants, ~2-6 months of age, were enrolled to receive 3 doses of oral QRV or placebo at 6-8 week intervals.

RESULT(S):
QRV was generally well tolerated; no serious vaccine-related adverse experiences were reported. No statistically significant differences were observed between vaccine and placebo recipients in the incidence of fever, irritability, vomiting, or diarrhea during the 14 days after any dose. Subjects were followed for AGE cases through one RV season. QRV was 74.6% efficacious [95% CI: 49.5%, 88.3%], p<.001, in preventing all RV AGE and 100% efficacious [95% CI: 43.5%, 100%], p=.003, in preventing severe RV AGE (RV AGE severity score >16 of 24). Of 11 QRV recipients with RV AGE, serotype G1 was identified in the stool of 10 (90.9%) and G2 in one. Of 39 placebo recipients with RV AGE, 26 (66.7%) had G1, 10 (25.6%) had G3, 2 had G2, and 1 had G4 identified in the stool.
A³3-fold rise in serum neutralizing antibody to G1 was observed in 57% (45/79) of vaccinees, and nearly 90% (162/185) exhibited a ³3-fold rise in serum IgA. A fecal anti-RV IgA response was observed in 65.4% (104/159) of vaccinees.

CONCLUSIONS(S):
QRV was generally well tolerated and was highly effective against RV.

LEARNING OBJECTIVES:
Understand QRV safety profile, efficacy.