KEYWORDS:
rotavirus vaccine, rotavirus gastroenteritis

BACKGROUND:
Rotavirus (RV) is the leading cause of dehydrating acute gastroenteritis (AGE) worldwide. Although the predominant RV serotypes vary geographically, G1, G2, G3, and G4 account for the majority of disease. We developed a reassortant rotavirus vaccine (RotaTeq™) containing 5 components (bovine rotavirus strain WC3 [P7G6] with one surface protein of either human serotype G1, G2, G3, G4, or P1). Earlier investigations have shown a quadrivalent (G1, G2, G3, P1) human-bovine reassortant (QRV) vaccine to be generally well-tolerated and highly effective against RV AGE and a refrigerator-stable buffered liquid G1+ G2 reassortant vaccine to be highly immunogenic.

OBJECTIVE(S):
We report preliminary results of a double-blind randomized placebo-controlled study of RotaTeq™.

METHOD(S):
During 1998-2000, 1946 healthy Finnish infants ~2-8 months of age were enrolled to receive 3 doses of oral vaccine or placebo ~4-8 weeks apart. Infants were randomized to one of 5 groups evaluating different vaccine potencies and reassortant compositions as follows (doses are per component): 5 x 106 pfu of RotaTeq™ (Group 1), 1.6 x 106 pfu of RotaTeq™ (Group 2), 5 x 105 pfu of RotaTeq™ (Group 3), 5 x 106 pfu G1+ G2+ G3+ G4 (Group 4), 5 x 106 pfu P1 (Group 5), or placebo.

RESULT(S):
Incidences of fever, irritability, vomiting, and diarrhea were generally comparable across all treatment groups, including placebo. Preliminary efficacy & 95% CI for all RV AGE regardless of serotype are: Group 1, 68.8% [41.6, 84.3]; Group 2, 76.6% [51.2, 90.0]; Group 3, 58.9% [26.1, 78.1]; Group 4, 63.6% [29.3, 82.6]; and Group 5, 48.3% [11.2, 70.7]. Percent of infants with ³3-fold rise in titer from baseline to postdose 3 for Groups 1-5 and placebo respectively are: (preliminary): G1 serum neutralizing antibody: 86.2, 73.3, 61.7, 84.4, 3.6 , and 1.1; serum IgA: 96.8, 91.1, 80.9, 92.8, 40.0, and 3.2; anti-RV stool IgA: 85.7, 79.6, 71.4, 86.0, 35.7, and 7.4.

CONCLUSIONS(S):
Preliminary results indicate that all vaccine potencies and compositions studied were generally well-tolerated and were efficacious against RV AGE.

LEARNING OBJECTIVES:
Understand safety, efficacy,and immunogenicity of RotaTeq^TM