Nucleoside analogues alone or combined with vaccination prevent hepadnavirus viremia and induce protective immunity : Alternative strategy for hepatitis B virus post-exposure prophylaxis

Objectives The current strategies for hepatitis B virus (HBV) post-exposure prophylaxis (PEP) are not generally available in remote and rural areas of developing countries and/or carry potential risks for infection with blood-borne transmitted pathogens. Nucleotide analogues (NAs) are successfully used for human immunodeficiency virus PEP, and maybe effective for HBV PEP. In this study, we tested the NA-based strategies for HBV PEP using the Chinese woodchuck model. Methods Chinese woodchucks were inoculated intravenously with different doses of woodchuck hepatitis virus (WHV). A deoxyguanosine analogue entacavir (ETV), a DNA vaccine pWHcIm, or ETV plus pWHcIm were applied to the infected animals 24 h later. Twenty weeks later, the animals were re-challenged with WHV to test for the presence of immunity against WHV. Results Inoculation with different WHV doses had a strong influence on the course of WHV infection; NA alone or in combination with a DNA vaccine completely prevented viremia after a high dose of WHV inoculation in Chinese woodchucks and induced partial or complete protective immunity, respectively. Conclusions NA-based PEP strategies (NA alone or in combination with vaccine) may be an alternative of HBV PEP, especially in those living in the remote and rural areas of the developing countries and the non-responders to the current vaccine, and may be valuable in the PEP of HBV and HIV co-infection after occupational and non-occupational exposure. Further clinical studies are warranted to confirm the valuable of NA-based strategies in HBV PEP.