The hepatitis B virus (HBV) vaccine is generally highly effective in preventing the disease, but some vaccinated individuals do not respond adequately to standard doses. The likelihood of poor response is higher for people with compromised immunity, such as those with HIV.

In a study described in the August 1, 2008 Journal of Infectious Diseases, Swedish researchers assessed the efficacy of a higher dose of the combination hepatitis A/hepatitis B vaccine (Twinrix).

As background, they noted that 5%-10% of individuals fail to develop protective levels (> 10 mIU/mL) of antibodies to hepatitis B surface antigen (anti-HBs) and are considered to be non-responders.

In this trial, 48 non-responders and 20 previously unvaccinated individuals received a double dose of the combined vaccine at 0, 1, and 6 months. Levels of anti-HBs and antibodies to hepatitis A virus (anti-HAV) were determined before vaccination and 1 month after each dose.

Results

Based on these findings, the investigators concluded that "Revaccination of nonresponders to the standard hepatitis B vaccine regimen with a double dose of the combined hepatitis A and B vaccine was highly effective."
They added, "This is most likely explained by the increased dose, a positive bystander effect conferred by the hepatitis A vaccine, or both."

Departments of Infectious Diseases and Clinical Microbiology, University Hospital, Linkoping, Sweden; Division of Clinical Virology, Karolinska Institute at Karolinska University Hospital, Huddinge, Sweden.

8/29/08

References

K Cardell, B Akerlind, M Sallberg, and A Fryden. Excellent response rate to a double dose of the combined hepatitis A and B vaccine in previous nonresponders to hepatitis B vaccine. Journal of Infectious Diseases 198(3): 299-304. August 1, 2008.

HM Diepolder. Can specific heterologous immunity boost hepatitis B vaccine responses? (Editorial commentary). Journal of Infectious Diseases 198(3): 297-298. August 1, 2008.