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  • Writer's picturePam King Sams

Pfizer’s Covid-19 Vaccine Proves 90% Effective in Latest Trials

Pfizer’s Covid-19 Vaccine Proves 90% Effective in Latest Trials

Drugmaker and partner BioNTech could seek FDA authorization by end of November

The global vaccine race entered a new stage on Monday as Pfizer reported that its vaccine was more than 94 percent effective.

That result — based on the first look at data from a late-stage U.S. trial involving nearly 44,000 people — is encouraging but preliminary, experts said. It is based on an analysis of 94 trial participants who contracted Covid-19.

Pfizer and its partner, the Germany-based BioNTech, said they expect to apply to the FDA for an emergency-use authorization before the end of the month, after they have collected sufficient data on the vaccine's safety.

The better-than-expected result is the first Phase III data from any of the four candidates now in the final stage of testing in the U.S. But there are still many questions about the vaccine and when it might be available for use.

Scientists are happy — but want more data

"I can’t imagine better news on the vaccine front," said Walid Gellad, director for the Center for Pharmaceutical Policy and Prescribing at the University of Pittsburgh. "Not only is it highly effective based on the press release, but there were 90 cases so we don’t have to deal with the skeptics about interim analyses, and there appeared to be no safety signals."

Others noted that the information Pfizer had released was promising but still incomplete, and had not been peer-reviewed or published in a scientific journal. "We should remain a little cautious, said Michael Head, a senior research fellow in global health at the University of Southampton in the U.K. "The provisional findings are made available in a press release, and the study is ongoing."

One important question is how long immune protection from the vaccine will last. The limited data that Pfizer released only reveals how the vaccine performed seven days after the second of two doses.

It's also not clear yet how well the vaccine will work for the elderly, whose immune systems are generally weaker than those of younger adults and children. A preliminary study suggested that older adults respond to the vaccine, but not as strongly as young or middle-aged people do.

Pfizer’s trial is also examining how well the vaccine works in people of color, who have been hospitalized and died at disproportionately high rates in the U.S., and in children as young as 12.

Paul Offit, a University of Pennsylvania vaccine expert who co-developed the rotavirus vaccine, said the early results were “very good news.” But he would like to see data on how the shot performs in various sub-groups, including the elderly, and whether anyone in the trial developed severe Covid-19.

Politicians cheered the news

President Donald Trump, who pushed unsuccessfully for a vaccine by Election Day, applauded the Pfizer result. "STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!" he wrote on Twitter.

President-Elect Joe Biden issued a statement congratulating "the brilliant women and men who helped produce this breakthrough," but cautioned that "the end of the battle against COVID-19 is still months away."


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