Acyclovir May Prevent Chickenpox

The varicella zoster virus (VZV) is easily acquired from household exposure, and the secondary case of chickenpox is often worse than the original. This study found that oral acyclovir prophylaxis greatly reduced chickenpox among family contacts.

Researchers compared 25 Japanese children who received prophylactic acyclovir with 25 untreated children. Treated children received 40 or 80 mg/kg of acyclovir four times daily for 7 days, beginning 7 to 9 days after the household exposure to varicella. Only 4 treated children developed clinical signs of chickenpox and only 1 had fever, although 21 (84%) developed VZV antibodies. In marked contrast, all 25 untreated children developed chickenpox, and 17 were febrile.