With the rollout of each coronavirus vaccine comes a big focus on efficacy, and new research on the Oxford-AstraZeneca version gets much more granular. In a study that has yet to be peer-reviewed, University of Oxford researchers found the two-dose vaccine was 76% effective at preventing symptomatic infections for three months after just one dose, which could "ease distribution challenges," as CNBC puts it. In fact, researchers say waiting longer to administer the second dose seems to be the way to go: When dose two was given within six weeks, there was 54.9% efficacy, compared to 82.4% when at least 12 weeks had passed.
That's not the only "absolutely superb" figure contained in the research, per the UK's health secretary. The researchers also found that the vaccine can majorly slow the transmission of COVID-19. The New York Times explains: Trial participants had their noses swabbed weekly to see if the virus was present. That's because even if they're infected, if the virus isn't present it can't be spread. Among those who'd been vaccinated, there were 67% fewer positive swabs, indicating the vaccine could shave down transmission by that much. CNN shares the researchers' perspective: If the vaccine was just making infections less severe, that swab positivity rate wouldn't drop. "A measure of overall ... positivity is appropriate to assess whether there is a reduction in the burden of infection," the researchers write. (Read more AstraZeneca stories.)