PARIS • A vaccine jointly developed by Pfizer and BioNTech was 90 per cent effective in preventing Covid-19 infections in ongoing phase 3 trials, the companies announced yesterday.
Protection in patients was achieved seven days after the second of two doses, and 28 days after the first, according to preliminary findings.
"The first set of results from our phase 3 Covid-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent Covid-19," said Pfizer chairman and chief executive Albert Bourla.
"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."
Following the news, the Russian Health Ministry said its Sputnik V vaccine against Covid-19 is more than 90 per cent effective, citing data collated from vaccinations of the public rather than from an ongoing trial.
"We are responsible for monitoring the effectiveness of the Sputnik V vaccine among citizens who have received it as part of the mass vaccination programme," said Professor Oksana Drapkina, director of a research institute under the Health Ministry. "Based on our observations, it is also more than 90 per cent (effective)."
World Health Organisation senior official Bruce Aylward described the news on the Pfizer-BioNTech trials as "very positive".
A Covid-19 vaccine may be rolled out by next March to the most vulnerable, which could fundamentally change the course of the pandemic, he said.
Across the globe, Covid-19 infection rates are hitting record highs.
Pfizer and BioNTech expect to supply up to 50 million vaccine doses globally this year, and up to 1.3 billion doses next year.
Bloomberg reported that the companies' study, which involved tens of thousands of volunteers, has been the most encouraging scientific advance so far in the battle against the coronavirus.
Pfizer shares rose by 8.4 per cent about an hour into trading after opening up 15 per cent from the previous close. BioNTech American depositary receipts gained 10.5 per cent, compared with 24 per cent at the open.
The trial findings are based on an interim analysis conducted after 94 participants contracted Covid-19. The trials will continue until 164 cases have occurred.
If the data holds up and a key safety read-out Pfizer expects in about a week also looks good, it could mean the world has a vital tool to control the virus that has killed over 1.2 million people.
Dr William Gruber, Pfizer's senior vice-president for vaccine clinical research and development, said: "This is about the best the news could possibly be for the world and for the United States and for public health."
With effectiveness for the first vaccines expected to be in the range of 60 per cent to 70 per cent, "more than 90 per cent is extraordinary", said BioNTech chief executive Ugur Sahin. "It shows that Covid-19 can be controlled. At the end of the day, it's really a victory of science."
The data does have limits. For now, few details on the vaccine's efficacy are available. It is not known how well the shot works in key sub-groups, like the elderly.
Also, it is not known whether the vaccine prevents severe disease, as none of the participants in this round of analysis were severe cases, Dr Gruber said.
US President-elect Joe Biden yesterday hailed the news as a "cause for hope" but warned of a long battle still ahead. "(It) is also important to understand that the end of the battle against Covid-19 is still months away," he said, stressing the importance of mask-wearing.
AGENCE-FRANCE PRESSE, BLOOMBERG