Low-dose intramuscular hepatitis B vaccination in medical students: 4-year follow-up.

Background: This is a report on the results of immunization of medical students with low-dose hepatitis B (HB) vaccine prior to starting clinical practice and evaluation of the efficacy of this vaccination scheme.

Methods: Low-dose (2 microg) recombinant HB vaccine was administered intramuscularly (im) at months 0, 1, 2 and 12 to 105 volunteers who wee HB surface antigen (HBsAg) and anti-HB core antigen (HBc) negative. Additional doses were administered after the third dose to the vaccines with anti-HBs titers below 10 IU/l.

Results: Protective anti-HBs levels (above 10 IU/l) were obtained in 73.3%, 95.6%, 100% and 92.8% of vaccines with geometric mean titers of 91, 61.6, 3,662 and 367 IU/l at months 3, 12, 13 and 44 months, respectively.

Conclusions: Long-term effective protection against HB could be obtained in medical students with this scheme. Low-dose HB im vaccination can be utilized as a cost-saving vaccination strategy.