COVID-19 Vaccine '90 Percent Effective,' Pfizer to Apply to FDA in November

A coronavirus vaccine being developed by American pharmaceutical company Pfizer Inc. is "more than 90 percent effective" at preventing COVID-19, the firm said Monday after an initial analysis of data from a large trial.

Pfizer, which is partnering with German biotechnology company BioNTech SE in the development of the vaccine, said that no serious safety concerns have been observed so far.

The companies expect to apply to the U.S. Food and Drug Administration for an Emergency Use Authorization (EUA) for the vaccine later in November once they have collected more safety data.

The data comes from the evaluation of 94 confirmed COVID-19 cases in a Phase III trial involving 43,538 participants, according to a Pfizer press release.

Pfizer expects to produce up to 50 million vaccine doses globally in 2020 and up to 1.3 billion doses in 2021.

"Today is a great day for science and humanity," Pfizer chairman Albert Bourla said in a statement on Monday.

"We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen."

The data is yet to be published in a peer-reviewed scientific journal, although Pfizer said it would do so once the Phase III trial had been completed.

"With today's news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis," Bourla said. "We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks."

The trial will end when a total of 164 participants in the trial are confirmed to have contracted COVID-19—a milestone that could be reached by November given the current infection rate in the United States, top Pfizer vaccine scientist Bill Gruber told Reuters.

Scientists around the world have been racing to develop a coronavirus vaccine—a tool that is considered a crucial weapon in the fight against the SARS-CoV-2 virus, which has killed more than 237,000 people in the United States and a total of 1.26 million individuals around the world.

The vaccine being tested in the Pfizer trial was administered in two doses given about three weeks apart. By examining which of the 94 COVID-19 cases had been given a placebo versus the actual vaccine and who became ill, the company concluded that the vaccine had an efficacy rate of 90 percent at seven days after the second dose. The company said that the final efficacy percentage may change once the trial has been completed.

While the news has been welcomed by scientists, some have urge caution about Pfizer's announcement of the early findings.

"At face value, this is exceptionally good news: a vaccine that is 90 percent effective at preventing symptomatic cases of COVID-19 and with millions of doses available by the end of the year," Eleanor Riley, a professor of immunology and infectious disease at the University of Edinburgh in the U.K., said in a statement. "However, the full data set on which the claim is based has not yet been released and so we don't know exactly what has been found."

"The two companies are at pains to point out that the trial participants are ethnically diverse, which is good, but say nothing about the age of people in the trial. We also know nothing yet about the severity of cases that were seen in the trial, whether infection or infectiousness was prevented, or how long the immunity is expected to last. But, I think we have reason to be cautiously optimistic."

Cronavirus CDC
This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses. CDC