The Prevalence of Hepatitis‐B Antigen (HBsAg) and Its Antibody (ANTI‐HBs) Among London Hemophiliacs and Blood Donors from London and Two Tropical Areas

Abstract

The prevalence of hepatitis-B antigen (HBsAg) and its antibody (anti-HBs) among 49 London [England] hemophiliacs was compared with that among women attending an antenatal clinic and healthy blood donors from London and from 2 parts of the tropics (Mauritius and Zambia). The prevalence of HBsAg and anti-HBs was low in antenatal patients, London blood donors and blood donors from Mauritius. A high proportion of hemophiliacs (59%) were anti-HBs positive, this being comparable with Zambian blood donors (53%), although anti-HBs titers in hemophiliacs were much higher (GMT 1:342) than in Zambian blood donors (GMT 1:36). HBsAg was detected in 29 of 250 (12%) Zambian donors but in only 3 of 49 (6%) hemophiliacs. Clinically overt hepatitis occurred in only 2 hemophiliacs. The presence of HBsAg-specific IgM [immunoglobulin M] in 7 of 29 (24%) anti-HBs-positive hemophiliacs suggests that a proportion of these patients recently experienced subclinical infection by hepatitis-B virus. Anti-HBs-positive hemophiliacs received a significantly higher number of cryoprecipitate units than did those without anti-HBs (P < 0.01). Of 7 hemophiliacs with high titers of anti-HBs, 5 (> 1:4096) showed a decline in titer after 1972 which possibly was associated with the introduction of screening of cryoprecipitate for HBsAg.