What’s the math behind proving a vaccine works? on the news they said double blind study, do they just say it works if less people get infected?

Question

I was listening to the radio and they were talking about covid vaccines undergoing trials and depending on the result they do or don’t get approved. How do they tell if it’s good. Do they just use a null hypothesis test? are there other options?

In: Mathematics

Answer 1

In a double blind study, there are people who get the vaccine and people who get a placebo. The decision of who gets which is completely random. Not even the people administering it know.

The reason for this is that they want to control for all other factors. If they gave a placebo but told people what it was, they might not take the same precautions going about their daily lives as if they were told they got the real thing. As a result, you might see the people with the placebo taking less risk, thus catching Covid less naturally, and polluting the placebo test.