Abstract 913 Poster Session IV, Tuesday, 5/4 (poster 150)

Rotavirus is the leading cause of dehydrating gastrointestinal disease in infants and children. Most current vaccine strategies require multiple reassortant strains and 3 doses of vaccine for protection. In this study, we evaluated an attenuated human rotavirus G1 [P8] strain, 89-12 vaccine. A randomized placebo-controlled, double-blind trial of 215 infants was performed at 4 centers in the U.S. Infants 9-16 weeks of age received 2 oral doses of vaccine (105 pfu) or placebo and were followed by active surveillance through one rotavirus season. Side effects were minimal with a significant increase only in mild transient fever after the first dose (19% vs. 5%) but not G.I. symptoms. Irritability was significantly decreased in vaccine recipients (34 vs. 49%). Rotavirus antibody (IgA or 89-12 neutralizing) was induced in 94% of vaccine recipients vs. 4% of placebo recipients. Rotavirus disease was detected in 2 of 108 vaccine vs. 18 of 107 placebo recipients (p < .001, efficacy 89%, C.I. 65-97%). All ten infants requiring medical attention received placebo (p < .001 vaccine vs. placebo). The total number of rotavirus infections was also significantly decreased in vaccine recipients (18 vs. 30; p = .05). Further evaluations of this highly effective rotavirus vaccine are warranted. Funded by Avant Immunotherapeutics, Inc.

Dr. Bernstein is also a consultant for Avant Immunotherapeutics, Inc.