UK Has Approved A Vaccine. Here's What Happens Next

Now that Britain has become the first western country to approve a Covid-19 shot, the spotlight shifts to the high-stakes rollout. Vaccinating the country's roughly 67 million people won't happen overnight. The UK has ordered enough doses of the two-shot Pfizer-BioNTech vaccine to immunize 20 million people.

Who will get the vaccine first?

The government plans to prioritize as it begins to deploy the vaccine, starting with residents and staff in care homes, then moving to people over 80 years old and health-care workers, documents show.

Britain will immunize people throughout the wider population next, based on age and risk. The shot is expected to be available from next week.

Here are the government's draft priority rankings:

• Residents in care homes and their carers
• All those 80 years of age and over, and frontline health and social-care workers
• All those 75 years of age and over
• All those 70 years of age and over. Clinically extremely vulnerable individuals
• All those 65 years of age and over
• All individuals aged 16 to 64 with underlying health conditions
• All those 60 years of age and over
• All those 55 years of age and over
• All those 50 years of age and over

How will people in the UK know when they can get a shot?

People will be contacted directly when it's their turn to get vaccinated, according to the Department of Health and Social Care. Until then, they should wait.

Where will people get it?

In the UK, 50 hospitals are ready to administer the vaccine, followed by doctors and pharmacists, assuming they have the facilities needed to store the doses, Health Secretary Matt Hancock said on Sky News Wednesday.

The country has moved to expand the pool of people who can give the jabs beyond the National Health Service to other health professionals.

"This is no different from any other vaccine," Sean Marett, who handles distribution for BioNTech, said at a briefing. "You go to your center, you roll up your sleeve, and you receive in your arm a vaccination."

Where is the vaccine at the moment?

The vaccine is still at Pfizer's production site in Puurs, Belgium. The doses will be shipped to the UK by truck or plane and become available there next week, according to BioNTech executives.

Can UK residents get more than one shot?

Not for now. The UK only cleared the vaccine made by Pfizer and BioNTech, although a product using a similar technology from Moderna Inc. may also get approved soon.

It may become possible to mix shots when other vaccines are approved. That should work for shots that target the spike protein of SARS-CoV-2, according to Andrew Pollard, who is leading the University of Oxford's vaccine trial with AstraZeneca Plc. The three front-runners use the spike protein as a target, as do many others in clinical tests.

How does the approved vaccine compare with others?

The product relies on a technology called messenger RNA, which has never been used to make approved vaccines before. So does Moderna's. Both showed they were more than 90% effective in clinical trials. The approach is designed to transform the body's own cells into vaccine-making factories.

The main difference is that the Pfizer-BioNTech product must be stored ultra-cold until a few days before it is used. Moderna's vaccine is stable at refrigerator temperatures for 30 days. Astra-Oxford's jab importantly can be kept at refrigerator temperatures.

BioNTech has been studying the vaccine's ability to withstand lower temperatures. In theory, all messenger RNA vaccines should have similar storage requirements, the company said. The vials can be transported at fridge temperatures for up to six hours, according to Marrett.

How do we know the product is safe?

Pfizer and BioNTech tested the vaccine in a clinical trial involving almost 44,000 people without observing severe side effects. The most common symptoms were fatigue and headaches.

The UK regulator, the Medicines and Healthcare Products Regulatory Agency, said on Wednesday that the vaccine "met its strict standards of safety, quality and effectiveness." Hancock described the review as having been "rigorous," not rushed.

Monitoring safety will be one of the biggest challenges once shots are rolled out widely, Emer Cooke, the new head of the European Medicines Agency, said in an interview last month.