Pfizer and BioNTech Say Their COVID-19 Vaccine Is More Than 90% Effective in Early Results

NEW YORK, Nov. 9 - Pfizer and BioNTech said Monday that their experimental COVID-19 vaccine prevented more than 90% of cases in a first look at late-stage trial data.

An independent Data Monitoring Committee ran the analysis on Sunday. It counted 94 confirmed COVID-19 cases among participants and found efficacy above 90%, measured from seven days after the second dose. The companies said protection is reached 28 days after the first dose of the two-dose schedule.

The trial began July 27 and has enrolled 43,538 people. As of Sunday, 38,955 had received their second dose. The companies had planned a first look at 32 cases, then moved it to at least 62 after talks with the Food and Drug Administration. The final analysis is planned at 164 cases, and the companies said the final efficacy figure may change as the study continues.

The committee reported no serious safety concerns. Pfizer expects two months of safety follow-up, the amount the FDA has specified for emergency use authorization, in the third week of November. The companies plan to file for that authorization soon after.

"Today is a great day for science and humanity," said Albert Bourla, Pfizer's chairman and chief executive. Ugur Sahin, BioNTech's co-founder and chief executive, said "more than 90% is extraordinary" and "It shows that Covid-19 can be controlled," according to Bloomberg.

About 42% of global participants and 30% of U.S. participants come from racially and ethnically diverse backgrounds, the companies said. Participants will be monitored for two years after their second dose.

Many questions remain open. The analysis has not yet looked at how well the vaccine works in key groups such as older adults. None of the cases counted were severe, so protection against serious illness is not known. How long protection lasts is also unknown. The companies plan to submit the full data for peer-reviewed publication.

Why it matters: Earlier expectations for the first vaccines were 60% to 70% effective. A result above 90% is well beyond that.

Supply will be limited at first. Pfizer and BioNTech said they expect to make up to 50 million doses this year and up to 1.3 billion in 2021. A rolling review of the vaccine had already begun in Europe last month. Regulators will now review the safety data, and Moderna, Johnson & Johnson and AstraZeneca are expected to report results of their own later.