An open-label randomized study to compare the efficacy of B (R) 20 microgram vaccine with HBVaxPro (R) (40 microgram/ml) vaccine in HIV-infected patients

Background: HIV and Hepatitis B (HBV) share similar routes of transmission. HBV infection is more frequent and more severe in HIV infected patients and therefore prevention of infection through vaccination is vital. Immunosuppressed patients have been shown to have a reduced antibody response following HBV vaccination. They are also less likely to maintain high protective antibody levels compared to immunocompetent individuals. The HBVaxPro 40 microgram/ml vaccine has been used in renal transplant patients and other non-HIV immunosuppressed individuals showing a higher rate of HepBsAb seroconversion.

Methods: Adult patients with documented HIV infection, a negative hepatitis B core antibody and no prior history of hepatitis B vaccination were recruited from December 2005. Patients were recruited from the Departments of Infectious Diseases and Genitourinary Medicine at North Manchester General Hospital and the Department of Genitourinary Medicine at Manchester Royal Infirmary. Consenting patients were randomised using a computer generated randomisation list. The patient then received either the Engerix B 20 microgram/ml vaccine or the HBVaxPro 40 microgram/ml vaccine at 0,1,6 months. Serology was checked at 3 months after the third dose and the vaccine considered efficacious if the hepatitis B surface antibody was greater than 100iu/l. We aim to recruit 190 patients in total. To date, 95 patients have been recruited. We have performed an interim analysis of the results available to date.

Results: From the 95 patients recruited to date, 64 patients had HepBsAb levels available. 27 patients had been randomised to the Engerix B 20 microgram/ml vaccine and 37 patients to the HepBVaxPro40 microgram/ml vaccine. Multivariant analysis demonstrated a trend towards increased effectiveness with the higher dose vaccine, 34% versus 15% (p=0.08). An undetectable (<40 copies/ml) HIV viral load at the date of the first vaccine dose was also independently associated within creased effectiveness, (p=0.02).

Conclusion: The use of the HepBVaxPro 40 microgram/ml vaccine currently remains a second line option for non-responders to the standard dose vaccine. This study supports others that have shown increased efficacy with its use as a first line vaccine in HIV-infected patients. HAART-mediated virological suppression has been shown to improve vaccine response in many studies including this one.