Viewer Question:What is the incubation period for fifth disease and for how long are you contagious if you do have it?
Doctor's Response:The incubation period -- the time that elapses between contracting parvovirus B19 (the virus of fifth disease) and the start of the illness -- is 4 to 12 days.
A person infected with parvovirus B19 is only contagious during the early part of the illness, before the rash appears.
This contagious period for fifth disease is different than that for many other rash illnesses, such as measles, for which the child is contagious while he or she has the rash.
By the time a child has the characteristic "slapped cheek" rash of fifth disease, he or she is no longer contagious and may return to school or to a child care center.
Last Editorial Review: 5/1/2002