Smiles from ear to ear at results of trial showing virus can be defeated
Interim conclusions of Pfizer trial show vaccine can provide protection against Covid-19 in announcement greeted with delight by Britain’s scientists
THE world finally turned a corner in the battle against coronavirus yesterday with the long-awaited announcement that there is now a vaccine which can prevent infection.
Although Pfizer Biontech are yet to publish full results, British scientists reacted with glee to the announcement, hailing the interim findings as “exciting”, “important” and “amazing”.
Professor Peter Horby, who is leading coronavirus drug trials at Oxford University, said the news had left him “smiling from ear to ear”, while Sir John Bell, who is leading Oxford’s vaccine team, said he believed life would be back to normal by spring.
“I’m really delighted with this result for no other reason than it shows you can make a vaccine against this little critter,” he added.
So what do we know about the vaccine? How will it work? When will it be available? And what hurdles are there still to surmount?
The science
Arguably the most fascinating aspect of the ‘BNT162B2’ vaccine is how it works.
Traditionally, vaccines are made up of small or inactivated doses of a virus, or its proteins, which t rigger an i mmune response when they are injected into the body.
But the Pfizer Biontech vaccine does something very different, and very clever. Instead of tiny bits of virus, the vaccine contains genetic code which instructs the body to actually build coronavirus proteins from inside the body.
It essentially turns the body’s cells into coronavirus molecule factories.
If that sounds scary, it isn’t, because the proteins created cannot assemble into the actual virus.
However, the immune system thinks it is under attack and begins to produce a defensive response.
If it then comes across the real virus in the future, it is already armed and ready to fight it off.
This new type is known as an ‘MRNA’ or ‘ messenger RNA’ vaccine, and experts believe it could be especially potent because it may trigger both parts of the immune system, the innate (which we are born with) and the acquired (which we develop as we come into contact with invaders).
Classical vaccines only trigger the acquired immune response, so ‘MRNA’ vaccines may provide an extra layer of defence. By getting the human body to produce the viral proteins itself, MRNA vaccines also shorten the manufacturing process which makes them easier and quicker to produce.
The same technology is being used to target cancer cells, encouraging the body to produce tiny tumour proteins to prime the immune system.
The trial
On March 17, Pfizer announced it was working on a coronavirus vaccine with Biontech, a little-known German company which had embarked on several new immunotherapy treatments.
By April 22, Germany had given approval for the first trials and 200 people received the first jab.
Successful early results saw a move to phase three trials on July 27, and 15 weeks later, nearly 44,000 people were enrolled in the trial, half of whom were given the vaccine, and half a placebo.
Participants in the US, Germany, Brazil, Argentina, South Africa and Turkey were given two doses, three weeks apart.
Less than eight months after the partnership was announced, Pfizer reported the news that everyone had been waiting for. The vaccine was more than 90 per cent effective in preventing Covid-19, and in fact, just 94 people had contracted the virus out of the tens of thousands who had enrolled.
No serious safety concerns were seen, and Dr Albert Bourla, Pfizer chairman, described the results as a “critical milestone”.
“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,” he said yesterday.
The team believes it will have enough safety data – around two months – to present to the Food and Drug Administration for Emergency Use Authorisation in the third week of November.
Professor Ugur Sahin, co-founder and CEO of Biontech, said: “This is a victory for innovation, science and a global collaborative effort. While we are all in the midst of a second wave and many of us in lockdown, we appreciate even more how important this milestone is on our path towards ending this pandemic and for us all to regain a sense of normality.”
The hurdles
However, as Boris Johnson said at yesterday’s press conference: “We’ve cleared one significant hurdle, but there are several more to go before we know the vaccine can be used.”
Crucial information about the vaccine is not yet available, such as whether it prevents severe cases, which result in hospitalisation and death, or whether it can be safely used on older people, who are most at risk.
There are also no details on whether it prevents people from transmitting the virus. If so, there will be a greater case for rolling it out more widely. If it simply prevents people from infection, then it makes more sense to vaccinate the elderly and vulnerable.
The vaccine has also only been studied for a few months, so it is not known how long immunity lasts. The results have not yet been published or peerreviewed by other scientists.
Previous data has shown that it can cause side effects, including aches and fever, and the vaccine still needs to be approved by the Medicines and Healthcare products Regulatory Agency.
Even if the vaccine passes all steps, Pfizer has said it can only deliver 50 million doses by the end of the year, 10 million of which are promised to Britain. However, each person needs two doses, so the maximum number of people who could be vaccinated in Britain this year is just five million.
There are also logistical challenges, as the vaccine has to be kept and transported in ultra-cold storage at below minus -109F (-78C).
Kate Bingham, the head of the UK Vaccine Taskforce, told MPS last week: “They may be relatively straightforward to manufacture initially, but the cost of deployment, and the complexity of deployment, is very high.
“We have to find better vaccine formats, so that we’re not dependent on such low temperatures and such complex chains.”
And there are fears that even if a vaccine is available, many people will refuse the vaccine because they feel it has been rushed.
Recent research has shown that around 36 per cent of people in Britain said they were either uncertain or very unlikely to be vaccinated against the coronavirus.
Dr Andrew Preston, reader in microbial pathogenesis at the University of Bath, said: “There is growing concern about public attitudes towards Covid-19 vaccines, with increasing numbers of people expressing doubts as to whether they would receive a vaccine when one becomes available.
“Lack of vaccine uptake could greatly compromise the effectiveness of global vaccine programmes, regardless of how good the vaccines are.”
Other British scientists also urged caution, warning that it may not be generally available for most of the population until well into next year.
Prof Gary Mclean, professor in molecular immunology at London Metropolitan University, said: “The vaccine is still some way off yet and will not immediately replace the established control measures currently in place.
“What must be remembered is that rolling out such a vaccine to the general population will be done in stages, with the most vulnerable and front-line responders first in line.
“Such a roll-out also depends on how many doses of vaccine can be manufactured and storage conditions – two doses are required and cold-chain must be observed.
“This will take time and effort, so will likely be well into 2021 before we see general availability.”
‘I’m really delighted about this result for no other reason than it shows you can make a vaccine against this little critter’