Serologic testing for protection against hepatitis B virus infection among students at a health sciences university in the United States.

OBJECTIVE: To evaluate hepatitis B vaccination coverage and documentation of vaccine-induced immunity.
DESIGN: Retrospective cohort analysis.
SETTING: Graduate school in the United States with programs in osteopathic medicine, dentistry, and allied health.
METHODS: Data collected included demographics, dates of hepatitis B vaccine doses, and postvaccination concentrations of antibody to hepatitis B surface antigen (anti-HBs), with dates. The proportions of students with anti-HBs of 10 IU/L or more by demographics, age at vaccination, interval since completion of the primary series, and response to additional vaccine doses were compared.
RESULTS: Of 3,452 students who matriculated during 2004-2009, 2,643 had complete data; 2,481 (93.9%) received 3 primary doses. Most were women (64.6%), US-born (85.6%), and white (63.2%); median age at receipt of the primary series was 14.5 years (interquartile range, 11.6-20.2 years) and at postvaccination testing was 23.2 years (interquartile range, 22.1-24.8 years). Of those who received 3 primary doses, 2,306 (92.9%) had an anti-HBs postvaccination concentration of 10 IU/L or more. Younger age at vaccination and longer time interval from vaccination to anti-HBs testing were associated with a postvaccination concentration of less than 10 IU/L (P< .001 and P = .0185, respectively, Cochran-Armitage test for trend). Almost all students (98.2%) who initially had less than 10 IU/L of anti-HBs, but then received at least 1 additional dose, had a follow-up anti-HBs concentration of 10 IU/L or more.
CONCLUSIONS: Almost all students had serologic evidence of protection against hepatitis B virus infection; most were vaccinated as adolescents and were tested more than 10 years after vaccination. Among students with anti-HBs concentrations of less than 10 IU/L, nearly all had 10 IU/L or more after at least 1 additional vaccine dose.