Infectivity
Symptoms begin some six days after exposure (between 4 and 28 days, with the average being 16 to 17 days) and last about a week. Infected patients with normal immune systems are contagious before becoming symptomatic, but probably not after then. Individuals with B19 IgG antibodies are generally considered immune to recurrent infection, but reinfection is possible in a minority of cases. About half of adults are B19-immune due to a past infection.
Read more about this topic: Parvovirus B19