Incidence of hepatitis B viraemia, detected using the polymerase chain reaction, after successful therapy of hepatitis B virus carriers with interferon–α

Thirty‐nine patients (62 sera) who, after interferon‐α therapy for chronic hepatitis B virus (HBV) infection, were seronegative for HBeAg and HBV‐DNA by dot blot hybridisation, were tested using the polymerase chain reaction (PCR) for residual viraemia. Overall, 59% of the HBsAg‐positive sera and 43% of the HBsAg‐negative sera were positive by PCR. All except one of the HBsAg‐negative patients had seroconverted to anti‐HBs. Between 13 and 18 months after therapy, 33% of the HBsAg‐positive and 20% of the HBsAg‐negative patients remained viraemic. Eighteen months after the end of treatment, no patient tested was positive. Twenty‐three patients were tested sequentially over periods from 1 to 43 months: Thirteen lost HBV‐DNA by PCR, three remained positive, five remained negative, and two patients relapsed. The merits and disadvantages of PCR for assessing interferon treatment of HBV carriers are discussed.