Effectiveness of a two-week worldwide lockdown against COVID-19

[Algr]

When they say that a vaccine is "90% effective" what is that relative to? If you had a disease that only 50% of the population were vulnerable to, and everyone got the vaccine, would that make 90% of the people immune? Or 95% of the people immune?

 

[OmCheeto]

When they say that a vaccine is "90% effective" what is that relative to? If you had a disease that only 50% of the population were vulnerable to, and everyone got the vaccine, would that make 90% of the people immune? Or 95% of the people immune?

It would appear that they don't overthink such things.

https://www.pfizer.com/news/press-r...ntech-conclude-phase-3-study-covid-19-vaccine

43000 participants​

170 total cases​

162 cases in the placebo group​

8 cases in the vaccine group​

(162 - 8) / 162 * 100% = 95.1%​

https://www.nih.gov/news-events/new...s-clinical-trial-nih-moderna-covid-19-vaccine

>30000 participants​

95 total cases​

90 cases in the placebo group​

5 cases in the vaccine group​

​

(90 - 5) / 90 * 100% = 94.4%​

​

https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section6.html

Vaccine efficacy or vaccine effectiveness​

 

[Algr]

Okay, thanks.

I was thinking of the notorious "lie detector" theoretical where a "90% accurate" lie detector ends up producing more false positives then actual positives. But I'm not sure if that applies here or not.

 

[OmCheeto]

Okay, thanks.

I was thinking of the notorious "lie detector" theoretical where a "90% accurate" lie detector ends up producing more false positives then actual positives. But I'm not sure if that applies here or not.

Ha! Please note that I've changed my post, as, while looking at the equation, although the answer came out fairly correct, it didn't strike me as making much sense.