Persistence of yellow fever vaccine RNA in urine.

To evaluate possible persistence of 17D yellow fever vaccine, we tested urine samples from 44 healthy recipients of yellow fever vaccine at varying times up to one year after vaccination. Urine samples from two vaccine recipients had detectable yellow fever virus RNA. The time since vaccination was reported as 21 days for one sample and 198 days for the other sample. These results suggest that yellow fever vaccine virus might persist for at least 6 months after vaccination in some people.