ON DECEMBER 2ND Britain became the first country to permit the general use of a fully tested covid-19 vaccine. The decision to grant this emergency authorisation had been made late the previous evening by the country’s Medicines and Healthcare-products Regulatory Agency (MHRA).
The vaccine licensed is code-named BNT162b2 and was developed by Pfizer, an American pharmaceutical giant, and BioNTech, a smaller German firm. It has an efficacy of 95%, a figure that seems consistent across a range of ages and ethnicities. Britain had already ordered 40m doses of BNT162b2 and Pfizer, as soon as it was informed of the decision, activated the procedures needed to start importing it from the site in Puurs, Belgium, where it is being made. The plan is to start vaccinating people on December 7th, and Matt Hancock, Britain’s chief health minister (pictured), has said that he expects “a matter of millions of doses” of the vaccine to be available in the country by the end of the year.
According to Pfizer, other countries are now looking to Britain and wondering if they can similarly speed up their regulatory processes. And the World Health Organisation, which runs an emergency licensing procedure for countries without medical regulators, said on December 2nd that it was in discussions with the MHRA about the details of that agency’s assessment, in order to expedite its own work in this area.
The speed with which this anticovid vaccine and others are moving through some of the world’s regulatory systems is a result of rolling reviews of their trials. Instead of waiting for firms to collate and submit full data-and-safety packages, regulators have studied results as they became available.
For some, though, things are not moving quickly enough. On December 1st, the day before Britain’s announcement, Stephen Hahn, the head of America’s Food and Drug Administration (FDA), was summoned to the White House to answer questions about why his agency has not moved faster to approve BNT162b2. As it happens, both the FDA and its counterpart in the European Union, the European Medicines Agency, have arranged public meetings in coming weeks in which covid-19 vaccines will be discussed ahead of regulatory decisions. Melanie Ivarsson, chief development officer at Moderna, an American firm that announced encouraging results for its own vaccine, mRNA-1273, a week after Pfizer and BioNTech, said these were important, as they allow independent experts to look at the safety and the analysis, and also let the public ask questions—something that will build confidence in these vaccines. “We want people to feel really comfortable,” says Dr Ivarsson.
Both BNT162b2 and mRNA-1273 belong to a class known as mRNA vaccines. Though this is the first time such a vaccine has been authorised for human use, experts are optimistic about their general safety because they have been tested in various cancer-related applications for over a decade. As to BNT162b2 and mRNA-1273 in particular, these have now been in trials involving 73,000 volunteers, half of whom have been given the vaccine and the other half a placebo of some sort. This constitutes a hefty set of data. And both vaccines seem to have been well tolerated, with no serious adverse events recorded.
On top of all this, health authorities have already laid safety-related follow-up plans, says Penny Ward, chairwoman of the education and standards committee of the Faculty of Pharmaceutical Medicine, a British group of doctors. These include systems for examining apparent adverse reactions and using anonymised health-care records to see how incidence of covid-19 varies between the vaccinated and the unvaccinated. One concern with any new vaccine is that it may increase the risk of infection in some groups. Another is that, in rare cases, vaccines trigger autoimmune reactions—something viral infections also do. With covid-19 vaccines being delivered to hundreds of millions, and then billions of people, much surveillance will be needed.
There are, as it happens, reasons to think that mRNA vaccines might actually be safer than some other kinds. Live vaccines (that against polio, for example) are weakened versions of the virus itself. This brings a risk that the virus will revert to a more dangerous form. With an mRNA vaccine, which is merely a bunch of strands of genetic material—mRNA—encapsulated in tiny spheres of fat, this cannot happen. This mRNA encodes not the instructions for how to make a virus, but rather how to make just one of its proteins, called spike. Thus directed, body cells turn out spike in quantity, and that stimulates a response which primes the immune system to react quickly if it comes across spike again—this time as part of an invading virus.
Also, mRNA is a natural component of living cells, which make and destroy it continuously. Its turnover rate is measured in days. So, once the mRNA from the vaccine has done its job it is quickly broken down. Yet misinformation is already being spread. One misconception is that the mRNA in the vaccine might alter a recipient’s DNA. Only in exceptional circumstances, though, is RNA transcribed into DNA in human cells.
Maintaining public trust in any authorised vaccine is important. That trust may be more forthcoming in Britain than in many places. Polls say 79% of the country’s inhabitants intend to get vaccinated against covid-19, which is above the international average. In America, for example, only 64% state such an intention.
But whose safety exactly?
Ultimately all decisions to approve medicines are made on a balance of risks versus benefits. For the approval of a vaccine, however, the likely benefits must vastly outweigh the possible risks. This is because, unlike drugs, which are generally prescribed to those who are already sick, vaccines are usually administered to healthy people.
The MHRA, for one, takes advice from an independent scientific committee in making its choices. But, though its members will have taken into account many factors when deciding to grant emergency authorisation to BNT162b2, one brutal calculation will surely have been near the fronts of their minds. This is that each day of waiting will be measured in lost lives. In Britain alone, on the day the government gave permission to use BNT162b2, covid-19 killed 603 people. ■
Correction (December 14th): A previous version of this article said that mammalian cells have no mechanism for transcribing RNA into DNA. In fact, one is provided by parasitic pieces of DNA called retrotransposons that the chromosomes of such cells play host to. Sorry for the mistake.
This article appeared in the Science & technology section of the print edition under the headline “An injection of urgency”