[Kronopath]

Always has been.

Now picture what would have happened if we had been willing to do challenge trials early on for COVID.

I encourage you to check out 1DaySooner, which the author mentions at the beginning of the article: https://www.1daysooner.org/

[lamontcg]

> Now picture what would have happened if we had been willing to do challenge trials early on for COVID.

Nothing significant would have changed. For example, on July 22, 2020 HHS announced $1.95B in funds for Pfizer for large scale manufacturing and distribution of 100 million doses of their vaccine. On Nov 18, 2020 the phase 3 clinical trials were completed. We didn't wait to know that they worked or not to start ordering the doses. It still took until April or so of 2021 to get that manufacturing and distribution completed because we'd never made nanoparticle vaccines commercially before at all and distribution itself was hard once we had the doses.

[Wowfunhappy]

An issue with doing a COVID-19 challenge trial that I heard from someone in this space at the time: Nobody actually knew how much virus to administer. We weren't sure of the normal quantity of COVID-19 a person typically inhales before becoming sick.

A major argument in favor of a challenge trial was that, for people who are young and otherwise healthy, COVID-19 isn't particularly deadly. However, we don't know what would have happened if we accidentally gave participants 10x the normal dose of COVID.

[s1artibartfast]

>An issue with doing a COVID-19 challenge trial that I heard from someone in this space at the time: Nobody actually knew how much virus to administer. We weren't sure of the normal quantity of COVID-19 a person typically inhales before becoming sick.

I dont think that is accurate. You dont have to know the actual viral quantity transmitted to create a representative transmission event. That is to say, if you know people can catch covid sitting side by side, that can be your challenge.

Even if the scenario isn't perfect, you still know how many people caught it vs placebo.

[this_user]

> Now picture what would have happened if we had been willing to do challenge trials early on for COVID.

Nothing much most likely. The mRNA vaccines were designed very rapidly after the virus itself had been sequenced. The thing that took time was moving through the different trial phases. Given that there was more than enough spread of the virus in the wild, deliberately exposing people might have shaved off a few weeks at most.

But the real bottleneck afterwards was production and roll-out of the vaccines anyway. So realistically, challenge trials would not have had any meaningful impact.

[s1artibartfast]

>The thing that took time was moving through the different trial phases. Given that there was more than enough spread of the virus in the wild, deliberately exposing people might have shaved off a few weeks at most.

I dont think that is accurate. You can run a challenge trial from exposure to outcome in weeks, whereas it takes many months and tens of thousands of people to get enough cases in the wild.

It may still be that production was the critical path, but challenge trials are much faster.