HIV organisations oppose active-challenge COVID-19 vaccine studies

Simon Collins, HIV i-Base

Numerous HIV community groups recently circulated a statement against the use of active challenge studies on COVID-19 vaccine studies. [1]

This was in response to a proposal in an open letter from a group of prominent scientists to directly expose volunteers on COVID-19 vaccine studies to SARS-CoV-2. [2] This proposal is also being considered by the Oxford Vaccine Group and had been discussed several months earlier in a paper in JID. [3, 4]

For many community advocates, the lack of an effective treatment for COVID-19 makes the proposal to use active challenge unethical. Even in younger paritcipants at lower population risk, COVID-19 related fatalities would just be a factor of chance and study numbers. Serious reactions to COVID-19 are also increasingly associated with long-term complications.

Also, importantly, the number of regions where incidence of COVID-19 are sufficiently high to evaluate responses to candidate vaccines. A recent letter in JID on the paper by Eyal et al discussed why challenge studies wouldn’t generate faster or more effective vaccines against COVID-19 and that because outcomes from SARS-CoV-2 are not self limiting, this approach is unethical. [5]


  1. AVAC and TAG. Statement on Human Challenge Studies for COVID-19 Vaccine Development. (17 July 2020).
  2. 1DaySooner. COVID-19 Human Challenge Trials.
  3. Coronavirus vaccine: Oxford team aim to start lab-controlled human trials. The Guardian. (16 July 2020).
  4. Eyal N et al. Human challenge studies to accelerate coronavirus vaccine licensure. JID, 221(11);1752–1756. DOI: 10.1093/infdis/jiaa152. (31 March 2020).
  5. Spinola SM et al. Human challenge studies are unlikely to accelerate coronavirus vaccine licensure due to ethical and practical issues. Journal of Infectious Diseases, jiaa457. DOI: 10.1093/infdis/jiaa457. (26 August 2020).

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