This is fantastic. CDC did weekly testing of frontline essential workers that received the mRNA vaccines to determine real-world efficacy rates. Full vaccination (14 days post two doses) had an efficacy against INFECTION, symptomatic or asymptomatic of 90% (CI of 68%–97%).
Partial vaccination (14 days post one dose) had an efficacy against INFECTION of 80% (CI of 59%–90%). Similar data from the UK and Israel found efficacy of one dose against infection of 72% (95% CI = 58%–86%) and 60% (95% CI = 38%–74%). So one dose seems to provide some protection against infection, but two dose protection against infection is much higher.
It is great to have such a thorough study on this. The retrospective observational studies of population case rates are less than ideal at measuring this sort of thing. And with weekly testing a lot more infection data was gathered than the phase III trials.
This is excellent for the prospects of herd immunity.
I think this data also supports what some countries like Indonesia are planning on doing of vaccinating high transmission risk persons instead of high risk for severe disease persons given scarce vaccine doses. These vaccines seem to have very high efficacy against preventing infection, symptomatic and asymptomatic.
