The Oxford/AstraZeneca COVID-19 vaccine grabbed headlines this week after a preprint study was lauded as the first evidence that the vaccine could prevent virus transmission.
The problem: The paper “does not prove or even claim that,” STAT reports.
What it did show: Fewer people were carrying the virus after being vaccinated, which would mean less virus circulating in a community. But that doesn’t prove the vaccine blocks transmission.
Standout stat: A single dose cut positive test results by 67%. The vaccine also appeared to reduce asymptomatic infections, ABC News reports.
Perplexing stat: Another striking finding was sidelined: 2 doses reduced positive test results by just 49.5%—flummoxing researchers.
“That one is hard to understand. How would efficacy go down after receiving a booster?” University of Florida biostatistician Natalie Dean, told STAT.