Smallpox and vaccinia
Smallpox is not, since 1979, present in the wild in the world, and immunisation is not now conducted against it as a routine.
The Smallpox vaccine, using a similar pox virus called Vaccinia, was always as well as being the first vaccine the most intrinsically dangerous commonly used one. When Voltaire reported that 60% of people caught Smallpox, and there was a 1 in 3 mortality among them, and the previous technique if inducing immunity - variolation - had a mortality on the order of 1-2% the balance of risk was favourable.
Current estimates of death rates in widespread Smallpox immunisation are on the order of 1-2 per million, which requires a significant risk of re-introduction to make favourable except for those tasked to deal with it.
The HIV epidemic has brought renewed interest in developing attenuated poxvirus vectors as future HIV vaccines[1] and perhaps the original smallpox vaccination itself actually protected against HIV[2].
References
- ↑ Esteban M. Attenuated poxvirus vectors MVA and NYVAC as promising vaccine candidates against HIV/AIDS. Human vaccines. Dec; 5(12):867-71.
- ↑ Weinstein RS, Weinstein MM, Alibek K, Bukrinsky MI, Beda B. Significantly reduced CCR5-tropic HIV-1 replication in vitro in cells from subjects previously immunized with Vaccinia Virus BMC Immunology, 11:23doi:10.1186/1471-2172-11-23