When to test hep B immunity
When giving hepatitis B immunizations, should we follow up with an antibody test to see if they’ve been effective? RICHARD McCAMMON, MD, Winnipeg, MB
Not in most cases. Ninety-five percent or more of otherwise healthy individuals will demonstrate seroprotective levels of antibody if tested following a standard three-dose series with hepatitis B vaccine. Given the high rate of response, routine serologic testing isn’t recommended for most vaccines, such as those in universal school-based programs. The decision whether to document seroconversion is primarily based on the reason why the individual is being vaccinated and the expected risk of future exposure. If a seroprotective level of antibody (>/= 10 IU/L) is detected post-vaccination then the individual is considered a responder and therefore immune. Post-vaccination testing for immunity is recommended for people at higher risk for hep B infection such as household contacts of a hepatitis B carrier or healthcare workers. This is because if sero-negative they will be offered a second series of vaccine. In addition, knowledge of prior seroconversion status will influence the decision on whether to treat with hep B immune globulin in the event of an exposure such as a needlestick injury.