The traditional smallpox vaccine, which was used in the smallpox eradication campaign 1958–1977, consists of a live vaccinia virus which can replicate in humans but usually does not cause disease. It can however sometimes lead to serious side effects.
Modified vaccinia Ankara virus is a highly attenuated strain of vaccinia virus that was developed in Munich, Germany between 1953 and 1968. It was produced by more than 500
serial passages of vaccinia virus (from a wild strain discovered by the Turkish vaccine institute of
Ankara) in chicken embryo
fibroblasts. After testing the safety and effectiveness as a vaccine, it was approved in Germany in 1977, and then given to about 120,000 people until 1980, when smallpox vaccinations ended in Germany. No severe adverse events were seen during this time. The vaccine is given
subcutaneously in two doses, at least 28 days apart. and in 2020 also against mpox and related
orthopoxvirus infections. It was approved in the European Union in 2013, as a vaccine against smallpox and in the US in September 2019, against smallpox and mpox. On 13 September 2024, the WHO has granted prequalification status to the MVA-BN vaccine, as the first vaccine approved for use against mpox. In August 2022, the US
Food and Drug Administration (FDA) gave
emergency use authorization for
intradermal (rather than subcutaneous) mpox vaccination using a lower dose of Jynneos, which would increase the number of available doses up to five-fold. The vaccination would still be given in two doses, 28 days apart. A 2015 study had tested a regimen of one-fifth dose given intradermally. == Development as a viral vector ==