MVA85A
MVA85A
Tuberculosis vaccine
MVA85A (modified vaccinia Ankara 85A) is a vaccine against tuberculosis developed by researchers led by Professor Helen McShane at Oxford University.[1] It is a viral vector vaccine and consists of an MVA virus engineered to express the 85A antigen once it infects a host cell. 85A is a cell-wall protein of the tuberculosis bacillus.
This vaccine produces higher levels of long-lasting cellular immunity when used together with the older TB vaccine BCG.[2] Phase I clinical trials were completed in 2008 and then phase II clinical trials took place in South Africa.[3][4] Efficacy trials ran in parallel from 2009 to 2019.[5] Results released in February 2013 were described as "disappointing", showing only a statistically insignificant prevention rate in infants.[6] A summary of animal studies published in 2015 cast doubt on the efficacy of the vaccine.[7]
In 2018, a BMJ investigation raised concerns about the ethics of an efficacy trial in South African infants, particularly because of results from earlier animal trials such as a study with macaques at Porton Down.[8] One response argued that 14 prior human trials showed a safety signal, that regulators were aware of the primate trial and decided to continue, and that three subsequent investigations found no evidence of wrong-doing.[9] Another response by Ian Orme questioned the critique of animal models.[10]