To the Editor.
—The desirability of universal immunization of young adolescents against hepatitis B virus (HBV) has recently been reemphasized by the National Coalition for Adult Immunization and the Centers for Disease Control and Prevention.1 On occasion, HBV serology is available in an unvaccinated child scheduled for immunization. If only 1 of the HBV antibodies is positive, a decision has to be made whether this is likely to be a false-positive result.In Quebec City, approximately 7000 fourth-grade children are immunized each year in the provincial program of universal immunization. In 1995, we conducted a prevaccination seroprevalence survey in these children. All children were eligible. Parents were called sequentially to participate in the study as soon as the consent form they had to sign to have their child immunized in the provincial program was received. The required sample size of 1200 was reached after calling 2014 parents. Among those