A “prime boost” approach may be a good way to generate simultaneous immune response against hepatitis C virus and HIV, raising the possibility of a combined vaccination, according to the results of a study presented at The International Liver Congress 2016 held in Barcelona this week.
In this approach, the immune system of study participants are first primed through exposure to nonreplicative serologically distinct adenoviral vectors that contain fragments of HCV and HIV viruses.
Following this, booster vaccinations are given with the same combination of HCV and HIV fragments, each inserted into an MVA vector, a vaccination virus strain commonly used in clinical trials.
“While we have drugs to treat both HIV and HCV, these are out of reach for many and do not prevent reinfection,” said Professor Lucy Dorrell of the University of Oxford, who is the principal investigator of the study.
The Phase 1 study enrolled 32 healthy volunteers in three groups. Group one received only HCV investigational vaccines at weeks 0 and 8. The second group received only HIV investigational vaccines following the same dosing schedule. The final group received both HCV and HIV investigational vaccines that were co-administered.
Vaccine priming against HCV and HIV induced immune response in the body, measured by the number of HIV and HCV specific T-cells found in a sample of blood (peak mean of 608.5 and 785 spot forming units per million peripheral blood mononuclear cells [SFU/106PBMC] respectively). These immune responses were increased following boost vaccination (peak mean 4260 SFU/106PBMC for HCV and 3760 SFU/106PBMC for HIV).
Co-administration of HCV and HIV components of the boost did not impair the magnitude or breadth of either HCV or HIV specific T-cell responses compared to each alone. All vaccines were given as an intramuscular injection and both were well tolerated.
European PEACHI Consortium. Prevention of HCV and HIV-1 infections through the induction of potent T-cell responses using prime-boost viral vector vaccine regimens. Poster session, Hall 8.0. Presented at: EASL, The International Liver Congress. April 13-17, 2016.