Saturday, January 22, 2011

Increased Potency of Inactivated Trivalent Polio Vaccine with Oil-in Water Emulsions

Since the Great Polio Eradication effort in 2000, four countries are still struggling with endemic levels of polio: India, Afghanistan, Pakistan, and Nigeria.  There has been social and political resistance to the polio vaccine, in these areas (especially Pakistan) but an even larger problem lies in the fact that the current vaccine (OPV, oral polio vaccine) has low seroconversion (antibodies for polio are not found at protective rates) and occasionally becomes infectious in certain geographical areas.  A new version of the vaccine, delivered by injection (IPV), seems like a more effective version of of the vaccine.  The major drawback, especially considering the countries that need the vaccine, is that the price of IPV is much higher than OPV.  
In an effort to create IPV at a lower cost, researchers are working on adding adjuvants to the vaccine.  This same method was utilized to make a greater number of H5N1 vaccines at a low cost.  Adjuvants are materials that can enhance the immune response so that a lower dose of the inactivated trivalent polio vaccine will be needed.  The researchers used multiple groups of rats for testing, one group was given the full dose of IPV and the other groups were given the vaccine with the various adjuvants.  The vaccine with adjuvants tested similarly to the vaccine alone on virus-neutralization titers.  The next step is to figure out the most effective adjuvant, based on the results and those commonly used in practice.


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