Rabies cell culture vaccines reconstituted and stored at 4 degrees C for 1 year prior to use protect mice against rabies virus

Human exposure to rabid dogs in developing countries is an ongoing problem that continues to demand effective, safe, and affordable post-exposure rabies vaccinations. Sheep and suckling mouse brain rabies vaccines used in developing countries are being replaced by expensive inactivated-virus cell culture vaccines. Human studies using cell culture vaccines have determined that cost is reduced and protection is maintained by injecting the unused portion of vaccines that have been reconstituted and stored refrigerated for 1 week. Here we determined whether reconstituted purified chick embryo cell and human diploid cell vaccine that had been stored at 4 degrees C for intervals up to 1 year elicit neutralizing antibody, and protect mice against rabies virus. Undiluted, or 1:5 and 1:25 dilutions of both vaccines injected immediately after reconstitution, or after reconstitution and storage at 4 degrees C for 1 week, 1 month, 3 months, 6 months or 1 year elicited high levels of neutralizing antibody and protected 100% of the mice injected with rabies virus.