(afaict) You're right about the 39 (risk reduction = 1-39/131 ~= 70%). But you're less correct about saying "smple size is probably too small" (in general, peo

(afaict) You're right about the 39 (risk reduction = 1-39/131 ~= 70%). But you're less correct about saying "smple size is probably too small" (in general, people really really really need to stop dismissing things based on sample sizes until they actually go through a Power calculation!). Your question about demographic breakdown is entirely valid. Hospitalization rate for covid is about 228.7 hospitalizations per 100,000 population [0]. Or, more easily interpretted, about 10-20% of cases turning to hospitalization. Taking the more conservative (10%) rate, we'd need 31 samples for a 95% CI and 5% margin of error. Thus, the interpetation is that is it unlikely that the _lack of seeing any hospitalizations in the vaccine+covid-positive group is by chance_. Hope that helps! [0] https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidvi...