Pfizer Soars as Vaccine Prevents 90% of Covid Cases in Study

A vaccine developed by Pfizer Inc. and BioNTech SE protects most people from Covid-19, according to a study whose early findings sent stock prices surging and were hailed by the top U.S. infectious-disease specialist as “extraordinary.”

The shot prevented more than 90% of symptomatic infections in the trial of tens of thousands of volunteers, the most encouraging scientific advance so far in the battle against the coronavirus. While the results are preliminary, they may pave the way for the companies to seek an emergency-use authorization if further research shows the vaccine is also safe.

Pfizer shares rose as much as 15% and were trading 11% higher at 12:52 p.m. in New York, while BioNTech American depositary receipts surged as much as 25%. The news fueled a global rally that added more than $1.8 trillion 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.

With effectiveness for the first vaccines previously expected to be in the range of 60% to 70%, a rate of more than 90% “is just extraordinary,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, on a call with reporters.

The data do have limits. 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, said William Gruber, Pfizer senior vice president for vaccine clinical research and development.

Outside researchers said they would need much more data, including the safety information, to assess how good the vaccine is. Assuming the encouraging early results are upheld and the vaccine is approved, use in the general public would still be a ways off, with those at the highest risk likely to get it first.

“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.”

Assuming the vaccine clears the final hurdles, attention will rapidly shift to rolling it out across the world. The challenges will be immense: The companies have agreed to supply deals with the U.S. government and with other countries, but it’s widely expected that front-line medical personnel, essential workers and at-risk groups will receive any authorized shot first.

U.S. states have been working on distribution plans, but many can’t finalize arrangements until it’s clear what shot will be given, as the top candidates have varying requirements for storage and transport. Pfizer’s vaccine, for example, must be kept at ultracold temperatures.

“The rollout of vaccines requires the near-flawless execution of an interconnected chain of processes,” according to an Oct. 21 report from the Boston Consulting Group. In addition to handling the products, officials will need to mount public education and outreach campaigns, monitor whether vaccines have any safety or efficacy issues once they reach a broader population, and

The Pfizer 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 Inc. 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 U.S. by around year-end.

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