Virginia’s Medicaid program has begun covering the cost of mosquito repellent to prevent Zika infection, the state health department said.

The program began covering repellent on Monday, the health department said.

It said that the virus can cause birth defects in babies of mothers were infected while pregnant. No vaccine exists to provide protection against the virus, so it is important to prevent bites from mosquitoes that carry it, the health department said.

A variety of conditions must be met to obtain the payment. Prescriptions are required, and the program allows one container of repellent for each prescription filled, the health department said. In addition, it said, one refill is allowed per month.