Background: Vaccination against hepatitis B virus (HBV) is recommended for all travelers visiting HBV-endemic countries. However, travelers often present with insufficient time for the standard HBV vaccine schedule (SVS). We examined seroprotection against HBV following an alternative two-visit vaccination schedule (TVS) with currently available vaccine products, and completion rates with this TVS.
Methods: A retrospective cohort study was conducted in three travel clinics in British Columbia, Canada. Adults ≥20 years old traveling to an HBV-endemic country, and unable to complete the standard or rapid HBV vaccination schedule before departure, were offered a TVS that consisted of a double dose of HBV vaccine at day 0, followed by a single dose in 4 to 12 months. Immunity to HBV [anti-HBV surface antigen (HBs) ≥10 mIU/mL] was determined 1 to 6 months following the final dose of HBV vaccine. Logistic regression modeling was used to assess correlates of seroprotection. We also determined completion rate with this TVS at two clinics.
Results: In total, 117 participants (age range, 21-81 years, median age 57) met the inclusion criteria. Of these, 97 (82.9%) were immune after the TVS. Immunity was demonstrated in 93.1% of patients <50 years old and 79.5% of patients ≥50 years old. Increasing age was associated with reduced odds of developing immunity to HBV using the TVS [adjusted odds ratio = 0.954, 95% confidence interval (CI): 0.904, 1.008]. The completion rate of the TVS was 32.6% over a 12-month period. Completion rates varied between clinics (23.5% vs 48.4%, p < 0.001), suggesting that clinic-specific follow-up policies were important.
Conclusion: Seroprotection with completion of this TVS was similar to or exceeded that published in the literature for the SVS by age. However, even with a TVS, completion rates were low, underscoring the importance of follow-up. Further research is needed to determine whether travelers are protected prior to completion of this TVS.
© 2014 International Society of Travel Medicine.