The potential of a combination vaccine that would provide protection against both hepatitis C and HIV has gotten one step closer to reality.
According to the Centers for Disease Control and Prevention, nearly 25 percent of people living with HIV also have HCV; and liver disease (often traced to hep C) is the leading cause of non-AIDS-related deaths among those with the co-morbidities. New therapies have been developed that offer a functional cure for hepatitis C, but currently no vaccine exists for either HIV or HCV — making the potential of a combination vaccination all more desirable.
A new study, presented today at The International Liver Congress in Barcelona, Spain indicates that priming the immune system could allow immunologists to trigger the production of both HIV and HVC antibodies.
Last year, scientists from The Scripps Research Institute, International AIDS Vaccine Initiative, and The Rockefeller University described a multiple stage process that could lead to a viable HIV vaccine. The approach relied on the idea of stimulating the immune system to make antibodies that will help it fight HIV. This “primes” the immune system so it is ready in advance of any exposure. Several other steps gradually improve the immune system’s ability to target and destroy HIV.
This new combination vaccine would work much the same way but antibodies would be developed for both viruses. As with the HIV-vaccine, the combo would also require a series of vaccinations to prepare the immune system to defend against any future viral intrusion.
"While we have drugs to treat both HIV and HCV, these are out of reach for many and do not prevent reinfection," noted Lucy Dorrell of the University of Oxford, referencing the prohibitively high costs of the new hep C cures.
Another researcher on the study, Ellie Barnes (who is leading the development of HCV vaccines at the University of Oxford) added, "knowing that it may be possible to vaccinate a single individual against both diseases opens up huge possibilities for rolling back epidemics of disease and co-infection."
In this Phase I study, 32 healthy volunteers were separated in three groups: one that received potential hep C vaccines at weeks zero and eight, the second group received potential HIV vaccines following the same dosing schedule; and the last group received both HCV and HIV vaccines administered at the same time.
In the groups that received vaccines for a single virus, the initial dose started the priming process, causing the immune system to develop defenses against HCV or HIV. Then the booster shot at week eight intensified the immune responses. All the vaccines were given as an intramuscular injection and were reportedly well tolerated.
The scientists discovered that the group receiving co-administration of HCV and HIV components had similar virus-specific T-cell responses as those receiving the single disease vaccines. The fact that they don't interfere with each other's level of immune response opens the way for the vaccines to be given at the same time.
European Association for the Study of the Liver Secretary General Laurent Castera lauded the results in a press release, saying, "Finding effective vaccinations against the world's biggest killers is a huge and pressing problem. This study shows for the first time that it is possible to generate simultaneous immune response against diseases HCV and HIV, raising the possibility of a combined vaccination."
Since this was just phase one, two additional phases of study must still occur before the combination vaccine can be approved by the Food and Drug Administration and made accessible to consumers. But being able to prevent HIV and hep C at the same time would certainly be worth the wait.