Pfizer says vaccine prevents 90% of Covid cases in study

The Covid-19 vaccine being developed by Pfizer Inc. and BioNTech SE prevented more than 90 per cent of symptomatic infections in a study of tens of thousands of volunteers, the most encouraging scientific advance so far in the battle against the coronavirus.

Eight months into the worst pandemic in a century, the preliminary results pave the way for the companies to seek an emergency-use authorization from regulators if further research shows the shot is also safe.

The news added more than $500bn to the value of the MSCI All Country World Index.

The findings are based on an interim analysis conducted after 94 participants, split between those who got a placebo and those who were vaccinated, contracted Covid-19. The trial will continue until 164 cases have occurred. If the data hold up and a key safety readout Pfizer expects in about a week also looks good, it could mean that the world has a vital new tool to control a pandemic that has killed more than 1.2 million people worldwide.

“This is about the best the news could possibly be for the world and for the United States and for public health,” said William Gruber, Pfizer senior vice president for vaccine clinical research and development. It was better than even the best result he had hoped for, he said.

With effectiveness for the first vaccines previously expected to be in the range of 60 per cent to 70 per cent, “more than 90 per cent is extraordinary,” BioNTech CEO Ugur Sahin said.

‘Victory of Science’

“It shows that Covid-19 can be controlled,” Sahin said in an interview. “At the end of the day, it’s really a victory of science.”

The data do have limits. For now, few details on the vaccine’s efficacy are available. It isn’t known how well the shot works in key subgroups, such as the elderly. And it isn’t known whether the vaccine prevents severe disease, as none of the participants who got Covid-19 in this round of analysis had such cases, Gruber said.

Outside researchers said they would need much more data, including the safety information, to assess how good the vaccine is.

“So far, it looks like it is promising,” said Peter Jay Hotez, a vaccine researcher and dean of the National School of Tropical Medicine at Baylor College of Medicine. “It helps provide proof of concept that it is possible to make a human Covid-19 vaccine.”

The vaccine is being tested in a two-dose regimen. The trial started in July, and since most participants only received their second dose much more recently, nobody knows how long any protection will last.

However, the strong reading from the first large-scale trial to post efficacy results bodes well for other experimental vaccines, in particular one being developed by Moderna that uses similar technology. Its big trial could generate efficacy and safety results in weeks. If that study succeeds as well, there could be two vaccines available in the US by around year-end.

Pfizer expects to get two months of safety follow-up data, a key metric required by US regulators before an emergency authorisation is granted, in the third week in November. If those findings raise no problems, Pfizer could apply for an authorisation in the US this month. A rolling review began in Europe last month, and Sahin said regulators there are working with BioNTech to “further accelerate the process.”

So far, the trial’s data monitoring committee has identified no serious safety concerns, Pfizer and BioNTech said.

Leading the Race

The positive preliminary data mean the US pharma giant and its German partner are on track to be first with a vaccine, after signing advance deals with governments worldwide for hundreds of thousands of doses. The companies have said they should be able to produce 1.3 billion doses — enough to vaccinate 650 million people — by the end of 2021. Only 50 million doses are expected to be available in 2020.

Pfizer has found itself drawn into a contentious political debate about how quickly regulators in the US should allow a vaccine to be given to Americans. President Donald Trump pushed to have a shot approved before Election Day, but regulators put in place rigorous standards that largely pushed that goal out of reach.

On Oct. 16, Pfizer CEO Albert Bourla said the companies could seek an emergency use authorisation from US regulators by late November if the trial results were to show the shot is safe and effective. Writing in an open letter, Bourla quelled fears that Pfizer might be racing the clock to bring out a vaccine before the presidential election.

Pfizer and BioNTech have a $2bn deal to supply 100 million doses to the US, with an option for 500 million more. Among the frontrunners, theirs is the only vaccine project that did not take funding from the White House-led Operation Warp Speed programme to bolster research, development or manufacturing. BioNTech received up to 375m euros ($445m) in development funding from the German government, however.

The shot relies on messenger RNA technology never before used in an approved medicine. Using mRNA, which essentially teaches the body’s cells to become vaccine factories, allowed it to be developed much faster than a traditional vaccine.

Pfizer had originally planned to conduct a first analysis of trial data after just 32 virus cases had occurred in the trial, which has enrolled 43,538 volunteers in multiple countries. Analyzing the data that early proved controversial among medical experts. Other companies working on vaccines planned to wait longer before scrutinising trial information.

After discussion with US regulators, Pfizer and BioNTech said they recently elected to drop the 32-case threshold and conduct the first analysis at a minimum of 62 cases. The assessment focuses on symptomatic Covid-19 infections, not merely those who test positive.

While Pfizer conducted those negotiations, it paused testing of participant samples for the virus, said Gruber. By the time Pfizer had made the changes in the trial plan and restarted virus testing a few days ago, some 94 cases had occurred, far more than the trial needed to meet the new threshold.

Blinded Data

Pfizer raced to verify the data, which were still blinded to almost everyone at the company beside a few statisticians. Early on Sunday afternoon, an independent data monitoring committee that included a noted statistician and four infectious-disease experts met in a closed video session to review the results for the first time. Afterward, the panel brought Gruber, Sahin and other company representatives onto the call and told them the vaccine had easily achieved its efficacy goal.

“Everyone is pretty ecstatic,” said Gruber. He said that further details on the case breakdown weren’t available.

Moderna is considered the next closest vaccine frontrunner. It has said it could get safety and efficacy data from its late-stage trial this month. Johnson & Johnson, which has a one-shot vaccine using a different technology, could get efficacy data from a final stage trial by the end of this year. AstraZeneca is also working on a vaccine using different technology, with results from studies in the UK and Brazil expected by year-end.