Disclaimer: I have been completely plugged out of Covid-19 stuff for over a year, definitely not an expert on these things (anymore), and definitely speaking for myself and not 1Day Sooner (which is more bullish on HCTs)
I worked for 1Day sooner last year as one of the main people investigating the feasibility and usefulness of HCTs for the pandemic. At least back then (March 2020), we estimated that it would optimiscally take 8 months to complete the preparations for an HCT (so not even the HCT itself). Most of this time would be used for manufacturing and approving the challenge virus, and for dose-finding studies. (You give people some of the virus and check if it’s enough to induce the disease, then repeat with a higher dose etc.)
I think in a better world, you can probably speed up the approval for the challenge virus, and massively parallize dose-finding to be less lenghty. Not sure how many months that gets you down to, but the 2.5 months for preparation + the actual HCT you assume seem overly optimistic to me. I still think HCTs should have been prepared, but I’m not sure how much speed that would have actually gained us. More details here in the section “PREPARATORY STEPS NEEDED FOR HUMAN CHALLENGE TRIALS” (free access)
There was also some discussion of challenge trials with natural infection (you put people together with infectious people who have Covid-19), which might get around this? But I don’t know what came out of that (I think it wasn’t pursued further?). Not sure how logistically feasible that actually is. (I think it would at least be more difficult politically than a normal HCT.)
Don’t think this changes the general thrust of your post, but wanted to push back on this part of it.
(There’s some chance I missed followup work, perhaps even by 1Day Sooner itself, that corrects these numbers, in which case I stand embarrassed :) )
On Human Challenge Trials (HCTs):
Disclaimer: I have been completely plugged out of Covid-19 stuff for over a year, definitely not an expert on these things (anymore), and definitely speaking for myself and not 1Day Sooner (which is more bullish on HCTs)
I worked for 1Day sooner last year as one of the main people investigating the feasibility and usefulness of HCTs for the pandemic. At least back then (March 2020), we estimated that it would optimiscally take 8 months to complete the preparations for an HCT (so not even the HCT itself). Most of this time would be used for manufacturing and approving the challenge virus, and for dose-finding studies. (You give people some of the virus and check if it’s enough to induce the disease, then repeat with a higher dose etc.)
I think in a better world, you can probably speed up the approval for the challenge virus, and massively parallize dose-finding to be less lenghty. Not sure how many months that gets you down to, but the 2.5 months for preparation + the actual HCT you assume seem overly optimistic to me. I still think HCTs should have been prepared, but I’m not sure how much speed that would have actually gained us. More details here in the section “PREPARATORY STEPS NEEDED FOR HUMAN CHALLENGE TRIALS” (free access)
There was also some discussion of challenge trials with natural infection (you put people together with infectious people who have Covid-19), which might get around this? But I don’t know what came out of that (I think it wasn’t pursued further?). Not sure how logistically feasible that actually is. (I think it would at least be more difficult politically than a normal HCT.)
Don’t think this changes the general thrust of your post, but wanted to push back on this part of it.
(There’s some chance I missed followup work, perhaps even by 1Day Sooner itself, that corrects these numbers, in which case I stand embarrassed :) )
Thanks! That is good knowledge.