Question: What are the rules for postvaccination testing following hepatitis B vaccination of health care workers (HCWs)?
Answer: HCWs who have a potential for exposure to hepatitis B should complete a three-dose series of hepatitis B vaccination. If they are delayed in receiving one of the doses, the series does not need to be restarted. One to 2 months following completion of the series, serologic testing should be performed. The antibody to hepatitis B surface antigen (anti-HBs) is the seriological marker of immunity to a previous infection, an immume response to vaccination, or the presence of passively acquired antibody. It is considered positive if the level is greater than 10 mIU/mL (see table in Hepatitis B facts: Testing and vaccination). If the anti-HB level is positive, then further postvaccination testing or periodic boosting with vaccine is not needed. If the postvaccination level is low (<10 mIU/mL), the vaccine series should be repeated with testing again 1 to 2 months following completion of the second series. If it is still low, then the HCW should be considered susceptible to hepatitis B and counseled on hepatitis B avoidance, but should not receive any more vaccine.
The Advisory Committee on Immunization Practices (ACIP) does not recommend periodic testing of immunized HCWs because anti-HB concentrations decline over time. Studies show that adults who respond to vaccination are protected for as long as 23 years, even if no anti-HBs are detectable currently. However, if the HCW has an exposure, then they should follow ACIP postexposure guidelines. If the HCW is uncertain of previous vaccination status or has no documentation of receiving the vaccine, then the CDC recommends that the series should be administered and postvaccination testing should be performed.
The variations in policy among sites occur because CDC recommends that if the employee or employer wants documentation of immunity, then a revaccination of the series can be done and serologic testing should follow.
Stephan L. Foster, PharmD
Professor and Vice Chair
College of Pharmacy
University of Tennessee
CAPT (Ret.) USPHS