Are vaccination programs working?
All eyes are on Israel, which has vaccinated roughly one-quarter of its population, for the first real-world evidence of a COVID vaccine’s efficacy. A preliminary analysis of people older than 60 who received the Pfizer–BioNTech vaccine found that it cut the chances of testing positive for the virus by a third at 2 weeks after the first injection, compared with a matched group who did not receive the jab. More conclusive results will come after people receive their second shot. “We were happy to see this preliminary result that suggests a real-world impact in the approximate timing and direction we would have expected,” says epidemiologist Ran Balicer.
The big question is how vaccines will change the course of the pandemic. Teasing apart the population-level effects of vaccines on a drop in COVID-19 cases from the impacts of other public-health interventions, such as social distancing and lockdowns, will be tricky. In places where outbreaks are rampant or lower-efficacy vaccines are being rolled out, it will be some time before immunization significantly reduces transmission. “But even with an imperfect vaccine, that population-level impact on deaths could still be quite substantial,” says epidemiologist Raina MacIntyre.
Nature | 5 min read
Variant can elude immune responses
Researchers are trying to make sense of a tsunami of laboratory studies released this week that raise concerns about some emerging coronavirus variants and mutations. Evidence is growing that some variants could evade immune responses triggered by vaccines and previous infection. But the picture is still murky.
Nature | 7 min read