[MrAlex94]

> Later, a vaccine candidate that has been proven safe in clinical trials could be given to a group of healthy adults in this age range, who are then exposed to the virus in a controlled environment. They would then be closely monitored by medics and researchers to see if the vaccine is successful in preventing infection, as well as identifying any side effects.

> https://www.thelancet.com/journals/lanres/article/PIIS2213-2...

I imagine they will do what they did for the vaccine candidate ChAdOx1 nCoV-2019 and swab at least every week to test for infection.

Do you have any source to back up your claim that a challenge trial wouldn’t work for SARS-CoV-2?

[CyanLite4]

When the asymptomatic rate is high, it’s hard to determine if the vaccine is truly works, and to what degree. If 40% of people are asymptomatic then that would theoretically mean that 40% of challenge trial participants won’t show symptoms. Does that mean the vaccine is working? Who knows. It could be working, it may also not work.

The only way to do it and get real results is to use a challenge trial only on the elderly population where the asymptomatic rate is low and where the symptoms are exaggerated. This would mean though that if the vaccine didn’t work you would overwhelm the hospital system with a lot of sick elderly people who require the most care, when the healthcare system is already overwhelmed.