[The significance of the isolated anti-HBc carrier. A study of 1797 drug addicts. The Intersert Group of Scientific Collaboration].

From 1985 through 1992 the following hepatitis B markers HBsAg, anti-HBs and anti-HBc were evaluated in 1797 injecting drug users (IDUs) attending 8 Centers for drug addicts in the Veneto region (north-east Italy). Among all IDUs, 1004 (56%) proved to be positive for at least one of the above markers. In particular our aim was to study the carriers of only anti-HBc. At entry, among these 1004 IDUs, 294 (29%) showed only the anti-HBc; 141 IDUs of them have been followed for a period of time: 77% remained without any marker change and 23% showed the appearance of anti-HBs. Subsequently, other 75 IDUs became carrier only of the anti HBc, for the following reasons: loss of anti-HBs (57%) or HBsAg (15%) appearance only of anti-HBc (28%). No carrier of only anti-HBc seroconverted for HBsAg. The evaluation of our data supports the hypothesis that the carrier status of the only anti-HBc prevents from reinfection by HBV and therefore these subjects do not need vaccination.