Prevalence of anti-HBc in anti-HBs positive individuals: implications for selecting vaccine candidates.

Two serologic markers, anti-HBs, -HBc, are useful to determine whether individuals at risk for hepatitis B virus infection are candidates for hepatitis B vaccination. To evaluate the usefulness of these markers in detecting immunity from prior infection (usually asymptomatic), 192 anti-HBs positive health care workers were tested for anti-HBc. In the 68% of individuals with anti-HBs RIA ratios greater than 10, anti-HBc was found in only 75%. In the group with anti-HBs ratios less than 10, only 6.6% had anti-HBc. Health care workers with frequent contact with blood and other body fluids were more likely to have both markers present. The incidence of the markers in this group was similar to that observed in 520 homosexually active males. The authors conclude that anti-HBs is more likely to identify prior immunity, particularly in individuals with infrequent HBV exposures.