As Boris Johnson said at a press conference on Monday: “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 it does, there will be a greater case for rolling it out more widely. If it simply prevents people from being infected, 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 peer-reviewed by other scientists. Previous data has shown that it can cause side effects including aches and fever, and it still needs to be approved by the Medicines and Healthcare products Regulatory Agency (MHRA).
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 this year is just five million. There are also logistical challenges because the vaccine has to be kept and transported in ultra-cold storage at below -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, is very high. We have to find better vaccine formats so that we’re not dependent on such low temperatures and such complex chains.”
There are fears that, even if a vaccine is available, many people will refuse it because they feel it has been rushed. Recent research has shown that around 36 per cent of people in Britain say they are either uncertain or very unlikely to be vaccinated against the virus.
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 ones 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 the vaccine may not be generally available for most of the population until well into next year.
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 we will likely be well into 2021 before we see general availability.”