MVA85A explained

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]

External links

Notes and References

  1. Web site: Professor Helen McShane FMedSci FRCP. Nuffield Department of Medicine, Medical Sciences Division. 2019-07-01.
  2. McShane H, Pathan AA, Sander CR, etal . Recombinant modified vaccinia virus Ankara expressing antigen 85A boosts BCG primed and naturally acquired anti-microbial immunity in humans . Nat Med . 2004 . 10 . 1240–44 . 10.1038/nm1128 . 15502839 . 11 . free .
  3. etal. Hawkridge T, Scriba TJ, Gelderbloem S, et al.. 2008. Safety and immunogenicity of a new tuberculosis vaccine, MVA85A, in healthy adults in South Africa. J Infect Dis. 198. 4. 544–52. 10.1086/590185. 2822902. 18582195.
  4. Ibanga H, Brookes R, Hill P, Owiafe P, Fletcher H, Lienhardt C, Hill A, Adegbola R, McShane H . Early clinical trials with a new tuberculosis vaccine, MVA85A, in tuberculosis-endemic countries: issues in study design . Lancet Infect Dis . 6 . 8 . 522–8 . 2006 . 16870530 . 10.1016/S1473-3099(06)70552-7.
  5. Web site: Improving BCG with MVA85A: An update on clinical trials. The Jenner Institute. McShane H. 2 October 2012. 23 September 2010. https://web.archive.org/web/20130814171058/http://www.tbvaccine2010.org/uploads/McShane__Helen_-_Thursday__September_23rd.pdf. 14 August 2013. dead.
  6. Web site: Tuberculosis vaccine hopes dashed. Fergus. Walsh. BBC News. 4 February 2013. 4 February 2013.
  7. Web site: Effects of MVA85A vaccine on tuberculosis challenge in animals: systematic review . Ije.oxfordjournals.org . 2015-09-09.
  8. Cohen. Deborah. 2018-01-10. Oxford TB vaccine study calls into question selective use of animal data. BMJ. en. 360. j5845. 10.1136/bmj.j5845. 0959-8138. 29321165. 196494376 .
  9. Ginsberg. Ann. Shea. Jacqui. Tameris. Michele. Hatherill. Mark. Hill. Adrian. McShane. Helen. 2018-01-26. Helen McShane and colleagues reply to Deborah Cohen. BMJ. Letters. en. 360. k236. 10.1136/bmj.k236. 0959-8138. 29374008. 46783593 .
  10. Orme. Ian M.. 2019-07-01. Re: Helen McShane and colleagues reply to Deborah Cohen. The BMJ. Letters. en.

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