Thread by @ashwin_id

I haven't seen the calculation for the protective benefit of a #sars_cov_2_vaccine against asymptomatic transmission yet, so here it goes : Suppl. Table 18 in the Moderna NEJM efficacy/safety manuscript: nejm.org/doi/suppl/10.1…

Asymptomatic infection at the time of dose #2 administration, appears to be diagnosed by PCR. For the placebo group there were 39 PCR+ infections out of 14598 people; for the vaccine recipients there were 15 out of 14550,

Vaccine efficacy is (((332-293)/14598)-(15/14550))/((332-293)/14598), or 61.4%, against asymptomatic infection.

Importantly, there does not appear to be a second sampling done at some interval after the 2nd dose. Therefore, it is possible that there was an even greater benefit against asymptomatic infection after two doses.

I cannot find similar data from Pfizer, even in the FDA filing, but hopefully those are coming. I want to assume similar protective efficacy, but that my optimism may be getting the better of me.

EDIT, INTERPRETATION: Taken together, the Moderna mRNA vaccine conferred 95% efficacy against symptomatic COVID-19, nearly 100% efficacy against severe COVID-19, and ~60% against asymptomatic infection before the 2nd shot.