Pfizer Inc's experimental Covid-19 vaccine is more than 90% effective based on initial trial results, the drugmaker said on Monday, a major victory in the war against a virus that has killed over a million people and battered the world's economy.
Scientists, public health officials and investors welcomed the first successful interim data from a large-scale clinical test as a watershed moment that could help turn the tide of the pandemic if the full trial results pan out.
However, mass roll-outs, which needs regulatory approval, will not happen this year and several vaccines are seen as necessary to meet massive global needs.
Pfizer and German partner BioNTech SE said they had found no serious safety concerns yet and expected to seek US emergency use authorisation this month, raising the chance of a regulatory decision as soon as December.
If granted, the companies estimate they can roll out up to 50 million doses this year, enough to protect 25 million people, and then produce up to 1.3 billion doses in 2021.
“Today is a great day for science and humanity,” said Pfizer Chief Executive Albert Bourla, noting the data milestone comes with “infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen.”
Experts said they wanted to see the full trial data, but the preliminary results looked encouraging.
“This news made me smile from ear to ear. It is a relief to see such positive results on this vaccine and bodes well for Covid-19 vaccines in general,” said Peter Horby, professor of emerging infectious diseases at the University of Oxford.
There are still many questions, such as how effective the vaccine is by ethnicity or age and how long immunity may last.
“But the bottom line is, as a vaccine it’s more than 90% effective, which is extraordinary,” top US infectious diseases expert Dr Anthony Fauci told CNN.
Pfizer expects to seek US emergency use authorisation for people aged 16 to 85. To do so, it will need two months of follow-up safety data to assure no side effects crop up.
That is expected to be available in the third week of November.
The US Health and Human Services Secretary Alex Azar said it would take several weeks for US regulators to receive and process the data before a potential approval.
MORE DATA NEEDED
To confirm the efficacy rate, Pfizer said it would continue its trial until there were 164 Covid-19 cases among volunteers. Bourla told CNBC on Monday that could be before the end of November.
Lawrence Young, a professor of molecular oncology at Britain’s University of Warwick, noted that the data may show the vaccine keeps people from getting sick but not necessarily from becoming infected.
“And the subtlety there ... is if you’re infected then you can still transmit the virus.”
Dozens of drugmakers and research groups around the globe have been racing to develop vaccines against Covid-19, which on Sunday exceeded 50 million cases since the new coronavirus first emerged late last year in China.
The Pfizer and BioNTech vaccine uses messenger RNA (mRNA) technology, which relies on synthetic genes that can be generated and manufactured in weeks and produced at scale more rapidly than conventional vaccines.
The technology is designed to trigger an immune response without using pathogens, such as actual virus particles.
The Trump administration has said it will have enough vaccine doses for all of the 330 million US residents who want it by the middle of 2021.