This is huge.
Until now, we've known that the mRNA vaccines are very effective at preventing disease, but it was an open question as to whether it was just reducing infections to asymptomatic levels where people could still spread the virus, or if it was reducing infections.
The study of Moderna subjects at the time of dose 2 (day 28) shows > 60% reduction in infections from just one dose. That is, for every 100 control patients infected in that period, < 40 experimental group patients got infected.
That's amazing, because we can assume that for the first 10-14 days, the groups performed the same...so almost all of that reduction came in the last two weeks...suggesting near complete protection as with the full disease.
Pfizer's vaccine is functionally VERY similar, so they're both likely effective this way. We expected this to be the case, but this is awesome confirmation.
By the time 60 million people get their first dose, this thing is going to be on the downslope. (20% vaccinated + 20% through disease = close enough to herd immunity to really bend the curve.)
Fauci, seems to agree and thinks that with the deployment and roll out of this vaccine en masse, the US could be seeing herd immunity as early as March or April of next year.