SAN FRANCISCO--A therapeutic vaccine against severe rotaviral diarrhea, which kills nearly 900,000 infants worldwide each year, has succeeded in clinical trials. The vaccine works best "to alleviate the outcome of the disease"--not necessarily to prevent it, says Chia-Lung Hsieh, senior director of vaccine development at Wyeth-Lederle Vaccines and Pediatrics. Described here at the annual meeting of the American Chemical Society, the company's vaccine, called RotaShield, is expected to be on the market by the middle of next year.
Hsieh announced that clinical trials involving 10,500 infants in nine countries showed that RotaShield limits the severity of the disease in 80% to 95% of cases. The vaccine consists of human viral proteins inserted into a similar virus affecting rhesus monkeys.
Experts were initially disappointed that prevention isn't the vaccine's strong suit, says pediatrician S. Michael Marcy of the Kaiser Foundation Hospital in Panorama City, California, a member of the American Academy of Pediatrics' Committee on Infectious Diseases. However, he says, the new vaccine will be a big improvement over existing treatments, which boil down to simply giving liquids to sick infants. For that reason, Marcy says, "this vaccine is a winner."
Although rotavirus sickens 3.5 million people--mostly infants--in the United States each year, it is deadliest in developing countries where access to health care is limited and hygiene is poor. It is also common in the southern United States and within African-American families, Hsieh says. She says that Wyeth-Lederle plans to recommend universal oral immunizations for babies at 2, 4, and 6 months of age.