The drugmaker Pfizer announced on Monday that an early analysis of its coronavirus vaccine trial suggested the vaccine was robustly effective in preventing Covid-19, a promising development as the world has waited anxiously for any positive news about a pandemic that has killed more than 1.2 million people.
Pfizer, which developed the vaccine with the German drugmaker BioNTech, released only sparse details from its clinical trial, based on the first formal review of the data by an outside panel of experts.
The company said that the analysis found that the vaccine was more than 90 percent effective in preventing the disease among trial volunteers who had no evidence of prior coronavirus infection. If the results hold up, that level of protection would put it on par with highly effective childhood vaccines for diseases such as measles. No serious safety concerns have been observed, the company said.
A vaccine – alongside better treatments – is seen as the best way of getting out of the restrictions that have been imposed on all our lives.
There are around a dozen in the final stages of testing – known as a phase 3 trial – but this is the first to show any results.
It uses a completely experimental approach – that involves injecting part of the virus’s genetic code – in order to train the immune system.
Previous trials have shown the vaccine trains the body to make both antibodies – and another part of the immune system called T-cells to fight the coronavirus.
Two doses, three weeks apart, are needed. The trials – in US, Germany, Brazil, Argentina, South Africa and Turkey – show 90% protection is achieved seven days after the second dose.
Pfizer believes it will be able to supply 50 million doses by the end of this year, and around 1.3 billion by the end of 2021.
However there are logistical challenges, as the vaccine has to be kept in ultra-cold storage at below minus 80C.
There are also questions about how long immunity lasts and the companies have not presented a breakdown of the vaccine’s effectiveness in different age groups.
Dr Albert Bourla, the chairman of Pfizer, said: “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.”
Prof Ugur Sahin, one of the founders of BioNTech, described the results as a “milestone”.
The data presented is not the final analysis. It is based on the first 94 volunteers to develop Covid – the precise effectiveness of the vaccine may change when the full results are analysed.
The companies say they will have enough safety data by the third week of November to take their vaccine to regulators.
Until then it is not possible for countries to begin their vaccination campaigns. The UK has already put in an order for 40 million doses, enough for 20 million people.
“This news made me smile from ear to ear,” Prof Peter Horby, from the University of Oxford.
“It is a relief… there is a long long way to go before vaccines will start to make a real difference, but this feels to me like a watershed moment.”
The news saw stock markets surge, with the FTSE 100 jumping by 5.5% – adding £82bn to the value of its shares and resulting in its best trading day since March.
The US and German companies say they can supply 50 million doses by the end of 2020 and 1.3 billion by the end of 2021.
The UK government has secured around 30 million doses – enough for 15 million people – in an agreement with the two firms.
Pfizer says that it will apply to the US healthcare regulator – the Food and Drug Administration – by the end of this month for emergency approval to use the vaccine.