Pfizer coronavirus vaccine is 90% effective, early data suggests

Large-scale trial to be continued as researchers look to confirm efficacy, while authorities insist that doses will be limited in coming months

Scientists have hailed a major breakthrough in the fight against Covid-19 after Pfizer and its German partner BioNTech announced that their vaccine appears to be 90 per cent effective in preventing disease, in what has been described as “a great day for science and humanity”.

The vaccine, tested on 43,500 people in six countries, has so far proven to be safe, raising hope that the pandemic could be brought under control by summer of next year.

It’s expected the green light for the vaccine could be granted in the coming weeks, with the UK government “hopeful” that doses will be made available for Christmas.

After the two pharmaceutical companies released their “fantastic” results, the prime minister, Boris Johnson, said the UK was preparing to advance its nationwide vaccination programme.

Although he said it was “very early days”, insisting that the country cannot afford to “slacken our resolve at such a critical moment”, the PM told a Downing Street press conference that the vaccine had cleared a “significant hurdle”.

The UK government has ordered 40 million doses of the Pfizer candidate, 10 million of which are due to be delivered by the end of the year if approval is granted, Downing Street said.

Protection is achieved 28 days after the initiation of the vaccination, which consists of two doses, meaning up to 5 million people in the UK could be inoculated over the winter period.

“I am hopeful, but not yet certain, that we could begin to see some vaccines by Christmas,” said England’s deputy chief medical officer Jonathan Van-Tam on Monday.

He described the vaccine announcement as a “huge milestone” and said it was good news for other future vaccines in development.

“It is good news for many other vaccines to come,” said Professor Van-Tam. “It's like getting to the end of the playoff final, it’s gone to penalties, the first player goes up and scores a goal.

“You haven't won the cup yet, but what it does is it tells you that the goalkeeper can be beaten.”

He said the Pfizer vaccine would be unable to stop the UK’s mounting second wave. “I'm hopeful that it may prevent future waves, but in this one we have to battle through to the end,” he said, adding “we have seen the swallow but this is not the summer”.

Alongside him, the PM agreed: “I don’t want to let people run away with the idea that this development today is necessarily a home run.” 

According to Monday’s announcement, those from black, Asian and minority ethnic communities also respond well to the vaccine.

Its efficacy rate is based on preliminary analysis, conducted by an independent data monitoring board, that looked at 94 infections recorded so far in Pfizer’s ongoing phase three trial.

The firm said it will continue to run the study until this figure rises to 164, at which point it will present all its findings to US regulatory authorities to seek approval.

As highlighted by the PM, the interim data has yet to be released or peer reviewed, and Pfizer said the initial protection rate might change by the time the study ends.

The longevity of the immune response provoked by the vaccine also remains unknown.

However, the findings are the most promising indication to date that a vaccine will be effective in preventing infection, handing humanity a crucial tool in tackling the pandemic.

“Once these vaccines begin to be deployed, then over a period of time they will make a significant difference to the kind of disease level we see in the UK at moment," Professor Van-Tam added.

“Whether they reduce transmission is something we do not know yet, and that is a crucial factor that will understand how far vaccines take us towards to the kind of future that you aspire to.”

Authorities have stressed that initial supplies of the vaccine will be limited. An estimated 50 million doses – enough to vaccinate 25 million people – are expected to be available globally by the end of the year.

From there, Pfizer aims to manufacture a total of 1.3 billion doses throughout 2021.

Pfizer and BioNTech have a £1.48bn contract with the US government to deliver 100 million vaccine doses beginning this year. Along with the US, the two firms have also reached supply agreements with the European Union, Canada and Japan.

England’s chief medical officer, Professor Chris Whitty, said the results demonstrated “the power of science against Covid”.

“We must see the final safety and efficacy data, but it is very encouraging,” he added. “It is essential we continue to suppress Covid but it is a reason for optimism for 2021.”

Professor Sir John Bell, a member of the government’s Scientific Advisory Group for Emergencies, said he was confident that life in the UK would start returning to normal by next spring – assuming regulatory approval for the vaccine is granted.

“I’m probably the first guy to say that, but I will say that with some confidence,” he told the BBC.

“I am really delighted with this result – it shows that you can make a vaccine against this little critter. Ninety percent is an amazing level of efficacy.”

Some experts have urged caution over the findings, saying it is not known how effective the jab is among the elderly – one of the most vulnerable groups – nor whether it can prevent people from passing the virus on to others.

“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,” said Eleanor Riley, professor of immunology and infectious disease at the University of Edinburgh.

“If a vaccine is to reduce severe disease and death, and thus enable the population at large to return to their normal day-to-day lives, it will need to be effective in older and elderly members of our society.”

The Pfizer jab uses messenger RNA (mRNA) technology, which relies on synthetically-produced genetic coding to generate an immune response in humans, and is produced at a scale more rapidly than conventional vaccines.

A number of other vaccines that use the same platform are also in development, including the Moderna jab, sparking hope that these candidates will be equally effective.

Richard Hatchett, chief executive of the Coalition for Epidemic Preparedness Innovations (Cepi), said: “We believe these interim results also increase the probability of success of other Covid-19 candidate vaccines which use a similar approach.”

However, this type of vaccine needs to be stored at temperatures as low as -80C, which is expected to hinder the distribution of doses across the world.

“This could create major logistical challenges for mass treatment outside major urban areas and in low or middle income countries,” said Andrew Hill, a senior visiting research fellow in the department of pharmacology at the University of Liverpool.

The FTSE 100 jumped more than 5.5 per cent in the wake of Pfizer’s announcement, adding £82bn to the value of its shares in the market's best day since March.

About 12 Covid-19 vaccines around the world are currently in the final stages of large-scale testing, but Pfizer is the first to report any results.

“We feel like we are on the cusp of one of the biggest medical advances for society and mankind in a 100 years that have passed here,” said Mikael Dolsten, the company’s chief scientific officer.

He added that there were tears of joy in Pfizer’s Connecticut office following announcement of the early results.

Dr Albert Bourla, Pfizer chairman and chief executive, said it was “a great day for science and humanity”.

Professor David Nabarro, the WHO special envoy on Covid-19, has meanwhile called for caution, saying there there it still some way to go.

“Everybody who's hearing and watching this will be saying 'wow, does this mean that life can go back to normal in the near future?' Life will go back to a new normal, and we're not there yet,” he said.

“Even if a vaccine arrives in the near future we've got many months of still dealing with the virus as a constant threat that we've got to make certain that we continue to do all that is necessary to solve the virus causing major problems.

“The vaccine will help, but it's not going to be a complete game changer.”