THE PREVALENCE OF ANTIBODY TO PARVOVIRUS B19 IN HEMOPHILIACS AND IN THE GENERAL-POPULATION

The prevalence of antibodies to parvovirus B19 (B19) was measured in t he sera of 566 hemophiliacs and 524 individuals of the general populat ion by immunofluorescence assays, using antigen expressed by the bacul ovirus system. In the general population, anti-B19 IgG seroprevalence was found to continuously decline from 64 percent at birth to 0 percen t in the age of 9-11 months and thereupon to increase to 61 percent in the age of 12 years. In younger adults and older people, Ige seroprev alence only slowly increased with age, reaching 77 percent in people a ged 60 and above. In contrast, in hemophilic children treated exclusiv ely with virally inactivated clotting factor concentrates, neither dec rease nor increase of B19 IgG antibody was detectable and the overall seroprevalence was 92 percent. In the group of hemophiliacs older than 12 years and treated before 1984 with non-inactivated clotting factor concentrates, 98 percent showed antibody to B19. Anti-B19 IgM seropre valence was significantly higher in hemophilic than in non-hemophilic individuals older than 12 years. Since it seems to be unlikely that th e high seroprevalence in hemophiliacs is acquired by immunization with inactivated viral antigen, the results suggest that infection with B1 9 is transmitted by clotting factor concentrates, even if subjected to virucidal methods.