Fluctuation of Viremia in Hepatitis B Virus-Infected Healthcare Workers Performing Exposure-Prone Procedures in the Netherlands

OBJECTIVE. To determine the longitudinal changes in viral load of hepatitis B virus (HBV)-infected healthcare workers (HCWs) and its consequences for exclusion of infected HCWs performing exposure-prone procedures, various HBV DNA safety thresholds, and the frequency of monitoring. DESIGN. Retrospective cohort study June 1, 1996-January 31, 2013. PARTICIPANTS. In the Netherlands, chronically HBV-infected HCWs performing exposure-prone procedures are notified to the Committee for Prevention of Iatrogenic Hepatitis B. Of the 126 notified HCWs, 45 had 2 or more HBV DNA levels determined without antiviral therapy. METHODS. A time-to-event analysis for HBV-infected HCWs categorized in various viremia levels surpassing a HBV DNA threshold level of 1x10(5) copies/mL, above which exposure-prone procedures are not allowed in the Netherlands. RESULTS. Fluctuations of HBV DNA in follow-up samples ranged from -5.4 to +2.2 log(10) copies/mL. A high correlation was seen for each HBV DNA level with the 3 previous levels. In a time-to-event analysis, after 6 months 7.2%, 6.5%, and 14.3% of individuals had surpassed the threshold of 1 x 10(5) copies/mL for viral load categories 4.8 x 10(3) to 1.5 x 10(4); 1.5 x 10(4) to 4.0 x 10(4); and 4.0 x 10(4) to 1.0 x 10(5), respectively. CONCLUSIONS. We propose standard retesting every 6 months, with more frequent retesting just below the high threshold value (1x10(5) copies/mL), and prolonging this standard interval to 1 year after 3 consecutive levels below the threshold in policies with lower safety thresholds (1x10(3) or 1x10(4) copies/mL).