The Application of Foot and Mouth Disease Vaccine Technology to the Production of an Inactivated Rabies Vaccine for Use on Animals

Summary

The production of an inactivated rabies vaccine, based on the Flury LEP strain of rabies virus grown in a BHK 21 suspension cell system and inactivated with aziridine, has drawn on well-established technology used for the production of foot and mouth disease (FMD) vaccines an the industrial scale. Experience gained from the use of thousands of millions of doses of FMD vaccine over a period of twenty years has established that the BHK 21 cell component is free of oncogenic effects and that the aziridine component also is free from either oncogenic or toxic effects. Aziridine is a first-order viral inactivant and is highly effective in inactivating rabies virus. The estimated half life for loss of infectivity during the process is 2.13 min.

High yields of rabies virus antigen can be produced in BHK suspension cell culture at the industrial scale; and vaccines with an average potency of 6 I.U./dose (modified NIH test—single dose) can be regularly produced. Such vaccines have given at least three years protection from challenge to dogs and are safe in all species.

Above certain minimal levels of offtake, inactivated rabies vaccines produced by an industrial scale suspension cell culture system can be competitive with both live modified vaccines and ‘in vivo’ produced inactivated vaccines in terms of production costs per dose. There is no reason why this technology can not be transposed in the manner that FMD vaccine technology has been transposed around the world should it become cost-effective to do so.