Covid vaccine: Pfizer jab 95% effective and safe, final analysis shows

Final analysis of the vaccine developed by Pfizer and BioNTech has shown that it is safe and 95 per cent effective in preventing Covid-19, paving the way for its imminent authorisation and global distribution.

The mRNA-based candidate has passed its full safety checks, Pfizer said, and is now ready to be presented to regulatory authorities for market approval.

Pfizer and its German partner BioNTech initially announced last week that their vaccine was more than 90 per cent effective, in what was hailed as a historic breakthrough in the fight against Covid-19. That rate was based on the analysis of 94 infections among participants in the phase three trial.

A total of 170 cases have now been recorded, enabling the two companies to provide a clearer verdict on the effectiveness and safety of their candidate. 

Of those volunteers who tested positive for Covid-19, only eight had been given the vaccine. The remaining 162 infections were observed in the placebo group.

Pfizer will present its large-scale trial data to the US Food and Drug Administration for approval of the vaccine “within days”.

The European Medicines Agency (EMA) said it has also received trial data from Pfizer and BioNTech for the agency's rolling review, but that approval has not yet been requested.

The UK government has secured 40 million doses in total of the vaccine, with 10 million due to be delivered to the country by the end of the year if the jab is approved.

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

Ugur Sahin, co-founder of BioNTech, said the data shows a high rate of protection against Covid-19 can be achieved “very fast” after the first dose.

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

Pfizer and BioNTech say there were no serious side effects from the vaccine, though some volunteers reported headaches and fatigue.

The companies’ large-scale phase three trial enrolled more than 40,000 people from across the world. Of these, 42 per cent of participants are from diverse ethnic backgrounds and 41 per cent are aged between 56 and 85 years old.

A good immune response was “consistent across age, gender, race and ethnicity demographics” and the jab was more than 94 per cent effective in those aged over 65, Pfizer said.

There were 10 severe cases of Covid-19 overall, with nine in the placebo group and one in the vaccine group.

Dr Charlie Weller, head of vaccines at the Wellcome Trust, said the additional data was “another bright moment in what has been a dark year”.

“Today’s update from Pfizer/BioNTech on the efficacy of their vaccine is highly encouraging. Such high levels of efficacy reported in over 65-year-olds surpasses all expectations we had for the first generation of Covid-19 vaccines. This group is amongst those most at risk of serious illness, and alongside healthcare workers must be prioritised to receive the first doses of any vaccines.”

The 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 technology are also in development, including the Moderna jab, which was shown this week in early data to be almost 95 per cent effective.

The UK has ordered five million doses of that jab, and also awaits the results of the Oxford University and AstraZeneca vaccine study, which is due to report soon.

Changes to the Human Medicines Regulations announced in October will allow the Medicines and Healthcare products Regulatory Agency (MHRA) to authorise temporary supply of vaccines if one becomes available before 2021. 

This means that if a vaccine is found to meet the safety, quality and effectiveness standards by the MHRA then vaccinations can begin without needing to wait for the European Medicines Agency. 

Matt Hancock, the health secretary, has said the NHS will be ready by 1 December to roll out any jab.

Albert Bourla, Pfizer’s chief executive, said the new study results “mark an important step in this historic eight-month journey”.

“We continue to move at the speed of science to compile all the data collected thus far and share with regulators around the world,” he added.

“With hundreds of thousands of people around the globe infected every day, we urgently need to get a safe and effective vaccine to the world.”

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.