This month has seen a torrent of news about experimental vaccines to prevent Covid-19, with the latest development from AstraZeneca and the University of Oxford. On Monday they announced that a preliminary analysis showed their vaccine was effective — especially when the first dose was mistakenly cut in half.

The announcement came on the heels of stunning reports from Moderna, as well as Pfizer and BioNTech. But AstraZeneca’s news was murkier, leaving many experts wanting to see more data before passing final judgment on how effective the vaccine may turn out to be.

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The front-runners in the vaccine race seem to be working far better than anyone expected: Pfizer and BioNTech announced this week that their vaccine had an efficacy rate of 95 percent. Moderna put the figure for its vaccine at 94.5 percent. In Russia, the makers of the Sputnik vaccine claimed their efficacy rate was over 90 percent.

“These are game changers,” said Dr. Gregory Poland, a vaccine researcher at the Mayo Clinic. “We were all expecting 50 to 70 percent.” Indeed, the Food and Drug Administration had said it would consider granting emergency approval for vaccines that showed just 50 percent efficacy.

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The drug maker Pfizer announced on Monday that an early analysis of its coronavirus vaccine trial suggested the vaccine was robustly effective in preventing Covid-19, a promising development as the world has waited anxiously for any positive news about a pandemic that has killed more than 1.2 million people.

Pfizer, which developed the vaccine with the German drugmaker BioNTech, released only sparse details from its clinical trial, based on the first formal review of the data by an outside panel of experts.

Continue reading “Pfizer’s Early Data Shows Vaccine Is More Than 90% Effective” →