The UK is now the first country to grant emergency approval to Pfizer and BioNTech’s Covid-19 vaccine

The first doses may begin rolling out next week.

The United Kingdom on Wednesday granted temporary authorization for emergency use of the Covid-19 vaccine developed by Pfizer and BioNTech to adults aged 16 and older, with the first 800,000 doses of the two-dose vaccine slated to be offered in the country next week.

This makes the UK the first country to approve the Pfizer/BioNTech mRNA-based vaccine and the first government approval of a vaccine backed by a clinical trial. (Some countries like Russia and China began administering their Covid-19 vaccines before completing large-scale trials.) It’s also the fastest a vaccine has ever gained approval, albeit on a temporary basis.

“I’m confident now, with the news today, that from spring, from Easter onward, things are going to be better,” said UK Health Secretary Matt Hancock during a press conference. “And we’re going to have summer next year that everyone can enjoy.”

The UK’s health regulator, the Medicines & Healthcare Products Regulatory Agency (MHRA), granted the temporary authorization shortly after Pfizer and BioNTech reported in November that their Covid-19 vaccine was 95 percent effective. Though this is a temporary authorization, the MHRA is conducting a rolling review of vaccine trial data as it comes in and may grant full approval at a later date. In contrast, the US Food and Drug Administration is evaluating vaccines based on completed studies, which increases the length of the approval process.

The UK government reached a deal with Pfizer and BioNTech to purchase 40 million doses of the vaccine through 2021 — enough for 20 million people — mainly shipped from Pfizer’s manufacturing plant in Puurs, Belgium.

“This authorization is a goal we have been working toward since we first declared that science will win, and we applaud the MHRA for their ability to conduct a careful assessment and take timely action to help protect the people of the U.K.,” said Pfizer CEO Albert Bourla, in a statement.

The UK has been one of the most severely afflicted countries during the Covid-19 pandemic, with 1.6 million reported infections and almost 60,000 deaths in a population of 66 million. The government recently imposed a second national lockdown as cases spiked; restrictions on movement and which businesses can stay open may begin to relax this week as the number of new cases declines. But with winter approaching, the risk of more Covid-19 spread in the UK remains high.

The UK is prioritizing older adults to receive a Covid-19 vaccine

With limited doses of the Pfizer/BioNTech vaccine to give out for the time being, the UK is establishing several priority tiers for Covid-19 immunization.

The country’s Joint Committee on Vaccination and Immunisation (JCVI) on Wednesday laid out guidelines for administering the vaccine based mainly on age. The top priority is residents and workers at care homes for older adults, a ranking based on the number of vaccinations that would be needed in each tier to prevent one death, not necessarily risk of exposure.

That’s why health workers, who will be at the front of the line in the US, are not in the top tier in the UK, even though they may be encountering the virus more frequently. “As the risk of mortality from COVID-19 increases with age, prioritisation is primarily based on age,” according to the guidelines.

Joint Committee on Vaccination and Immunisation

The committee divided its overall priority list into nine groups. “It is estimated that taken together, these groups represent around 99% of preventable mortality from COVID-19,” according to the JCVI guidelines.

But the guidelines also note that vaccine deployment strategies may have to shift to address concerns like mitigating health inequalities and logistical challenges. The latter is particularly important for the Pfizer/BioNTech vaccine because it has some of the most stringent cold storage requirements of any Covid-19 vaccine candidate: temperatures of minus 70 degrees Celsius (minus 94 degrees Fahrenheit) or lower. While Pfizer and BioNTech are developing shipping containers that can maintain these temperatures for 30 days, it’s likely the first facilities to receive it will be major health facilities that already have freezers.

Recipients will have to receive the vaccine as two doses spaced 21 days apart, so rigorous patient tracking will be needed as well.

The US is now waiting on emergency approval for two Covid-19 vaccines

Advisers to the Centers for Disease Control and Prevention this week voted on US guidelines for vaccine approval. The recommendations from the Advisory Committee for Immunization Practices stated that health workers and residents of long-term care facilities should be up first for a Covid-19 vaccine. That health workers are in the top tier stands in contrast to the guidelines issued by the UK.

Establishing these priorities are all the more critical now that a vaccine is poised to begin distribution in the US in weeks. Pfizer and BioNTech have also applied for an Emergency Use Authorization (EUA) in the US from the FDA for their Covid-19 vaccine. The FDA is meeting on December 10 to discuss their vaccine. This week, Moderna, another mRNA Covid-19 vaccine developer, also applied for an EUA.

If granted, these emergency approvals would mark the fastest vaccine development timeline ever, an amazing feat against an unprecedented pandemic. But Covid-19 cases are continuing to rise across the US, and it will still be a few more months before there is widespread access to a vaccine.