Hepatitis C vaccine
A hepatitis C vaccine, a vaccine capable of protecting against hepatitis C, is not available. Although vaccines exist for hepatitis A and hepatitis B, development of a hepatitis C vaccine has presented challenges.[1] No vaccine is currently available, but several vaccines are currently under development.[2]
One effort has involved use of the hepatitis B core antigen.[3] In a 2006 study, 60 patients received four different doses of an experimental hepatitis C vaccine. All the patients produced antibodies that the researchers believe could protect them from the virus.[4] Nevertheless, as of 2008 vaccines are still being tested.[5][6] Some efforts have entered Phase I/II human clinical trials.[7]
SynCon will test a new HCV vaccine in humans in 2013. SyCon's HCV vaccine can generate robust T-cell responses not only in the blood, but also in the liver—an organ known to suppress T-cell activity.
Most vaccines work through inducing an antibody response that targets the outer surfaces of viruses, but the Hepatitis C virus is very variable. Since the antibody approach alone is not going to work, researchers are taking a different strategy, which is to induce the T cell arm of the immune response using viral vectors, adenoviral vectors that contain large parts of the hepatitis C virus genome itself, to induce a T cell immune response against hepatitis C.
Most of the work to develop a T cell vaccine has been done against a particular genotype. There are six different genotypes which reflect differences in the structure of the virus. A final vaccine approved for humans will need to take all six genotypes into account to be an effective prophylactic vaccine. A prophylactic vaccine works by preventing infection in the first place, and the idea here is that when you give someone a vaccine you induce the immune response so that it has a head start. Then when the person is exposed to the virus the immune system is already set in play. Conversely, with a therapeutic vaccine you are trying to get rid of an infection that is already well established, and that is much more difficult to do.
References [edit]
- ^ Randal J (June 1999). "Hepatitis C vaccine hampered by viral complexity, many technical restraints". J. Natl. Cancer Inst. 91 (11): 906–8. doi:10.1093/jnci/91.11.906. PMID 10359539.
- ^ Strickland GT, El-Kamary SS, Klenerman P, Nicosia A (June 2008). "Hepatitis C vaccine: supply and demand". Lancet Infect Dis 8 (6): 379–86. doi:10.1016/S1473-3099(08)70126-9. PMID 18501853.
- ^ Chen JY, Li F (December 2006). "Development of hepatitis C virus vaccine using hepatitis B core antigen as immuno-carrier". World J. Gastroenterol. 12 (48): 7774–8. PMID 17203519.
- ^ Edell, Dean (2006). "Hepatitis C Vaccine Looks Promising". ABC7/KGO-TV. Retrieved 2006-07-04.
- ^ Strickland GT, El-Kamary SS, Klenerman P, Nicosia A (June 2008). "Hepatitis C vaccine: supply and demand". Lancet Infect Dis 8 (6): 379–86. doi:10.1016/S1473-3099(08)70126-9. PMID 18501853.
- ^ HCV Vaccine Development
- ^ Halliday, J.; Klenerman, P.; Barnes, E. (May 2011). "Vaccination for hepatitis C virus: closing in on an evasive target.". Expert Rev Vaccines 10 (5): 659–72. doi:10.1586/erv.11.55. PMC 3112461. PMID 21604986.
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