The Story:
Most drugs — both vaccines and therapeutics — are accepted as safe and effective without ever having to prove themselves in “human challenge” trials. A human challenge trial — in which a volunteer is vaccinated, then immediately exposed to the disease, in order to see how effectively the vaccine protects him — is disfavored for obvious reasons. The vaccine can fail, the volunteers can get sick, and some of them may die. But in the extraordinary circumstances posed by the present pandemic, a human challenge is set to begin.
Significance:
In a normal clinical trial of effectiveness, the volunteers are inoculated, but then simply allowed to go about their normal lives, for a period of months. If over those months, the inoculated group has been less likely to contract the virus than the members of a control group, the vaccine is deemed effective. But that requires a wait-and-see period, and there is a desire, literally around the world, that testing for vaccines against Covid-19 be hurried. Thus, the human challenge.
In Pill Form:
The tests will begin in London England in January. Authorities in the USA have not issued approval for any human challenge trials here.
