> Human challenge studies are used to test the efficacy of therapeutics and vaccines, not to test the pathogen itself. Actually, you're wrong. https://www.gov

> Human challenge studies are used to test the efficacy of therapeutics and vaccines, not to test the pathogen itself. Actually, you're wrong. https://www.gov.uk/government/news/worlds-first-coronavirus-human-challenge-study-receives-ethics-approval-in-the-uk https://www.gov.uk/government/news/worlds-first-coronavirus-... : Published 17 February 2021 : Due to begin in the next few weeks, it will involve up to 90 carefully selected, healthy adult volunteers being exposed to the virus in a safe and controlled environment. : The safety of volunteers is paramount, which means this virus characterisation study will initially use the version of the virus that has been circulating in the UK since March 2020 and has been shown to be of low risk in young healthy adults. Note that this study was in 2021, after the virus had already mutated. In order to ensure that the volunteers are infected with a specific virus version they would have to have cultured it. : Once this initial study has taken place, vaccine candidates, which have proven to be safe in clinical trials, could be given to small numbers of volunteers who are then exposed to the Covid-19 virus, helping to identify the most effective vaccines and accelerate their development. As shown here, the first cohort would not have been given a vaccine. But would have been used to characterize the activity of the virus on healthy humans.