Rotaviruses, a major cause of gastroenteritis, generate 500,000
doctor visits and 50,000 hospital stays in the United States
every year, Moskowitz says. Elsewhere they are far deadlier:
diarrheal infection is one of the top five causes of death
worldwide. Wyeth's rotavirus vaccine, RotaShield, was withdrawn
five years ago after a severe side effect (intussusception, a
potentially fatal telescoping of the intestine) appeared in 20
out of 1 million US infants within one month of vaccination.
Moskowitz says Wyeth's vaccine was derived from the Rhesus
monkey, whereas Merck's has a bovine source. Now in a Phase III
safety study of 30,000 infants, RotaTeq has shown no serious
side effects to date. The company expects to file a Biologics
License Application (BLA) next year. Varivax [varicella zoster
virus vaccine] A more potent formulation of Merck's chicken pox
vaccine, Varivax, now in Phase III, could become the first
product to prevent shingles, the recrudescence of the childhood
ailment in adults. More than 35,0