Seroprevalence of hepatitis B surface antigen (HBsAg) among first-time and sporadic blood donors in Greece: 1991-1996.

Hepatitis B surface antigen (HBsAg) seroprevalence among three major groups of sporadic voluntary blood donors in Greece was studied and compared to the seroprevalence in regular donors. These three groups share many characteristics with the general population. A 6-year retrospective seroepidemiological study was carried out (1991-1996). The study population consisted of donors who were (i) military recruits (n = 80 302), (ii) enlisted military personnel (n = 86 920) and (iii) directed family donors (n = 75403). A specimen was considered as HBsAg positive when found repeatedly reactive by a 3rd-generation immunoassay and confirmed by RIA. The Mantel-Haenszel chi2 procedure was used for stratified analysis of the prevalence rates and Greenland/Robins confidence intervals of the respective weighted relative risk (MHRR) were calculated. The 6-year overall HBsAg seroprevalence among the three sporadic donor groups was 0.84%; this was twice the seroprevalence among a sample of regular donors (n = 45504) in Greece. Seroprevalence was higher among enlisted personnel (1.21 < MHRR = 1.34 < 1.50), during years prior to 1995. Directed family donors had the same overall seropositivity rate as recruits and enlisted personnel. After 1995, all groups had a seroprevalence below 1%, possibly indicating a shift towards lower endemicity in the Greek population.