Vaccination against Covid-19 will begin early next week after the UK became the first country in the world to approve a jab from Pfizer and BioNTech.

Here, the PA news agency answers key questions surrounding its rollout and how it works.

– Who will get the coronavirus vaccine first?

The Joint Committee on Vaccination and Immunisation (JCVI), which advises ministers, has recommended that care home residents and staff should be prioritised.

However, due to difficulties transporting the Pfizer/BioNTech jab, most care home residents will need to wait.

Sir Simon Stevens, chief executive of NHS England, said the first people to receive the jab would be the over-80s, care home staff and others identified by the JCVI who may already have a hospital appointment.

But he told a Downing Street press conference the NHS was “raring to go” to vaccinate people in care homes, hopefully this month.

– How many doses does the UK have access to?

The UK has ordered 40 million doses of the the Pfizer/BioNTech jab, enough to vaccinate 20 million people with the required two doses, given 21 days apart.

Health Secretary Matt Hancock said 800,000 doses of the jab will arrive next week, with millions more arriving in the coming weeks.

– Is there a timetable for vaccination?

Sir Simon, chief executive of NHS England, said that rollout of the vaccine will start at 50 “hospital hubs” in England next week.

The bulk of vaccinations will take place in “January through to March or April for the at-risk population”, he added.

– Does that mean restrictions will now be eased?

Not yet. Prime Minister Boris Johnson said that it will be “long, cold months” before all of the most vulnerable are protected.

“So it’s all the more vital that as we celebrate this scientific achievement we are not carried away with over-optimism or fall into the naive belief that the struggle is over,” he told a press conference.

– Okay, so how does the the Pfizer/BioNTech vaccine work?

Conventional vaccines are produced using weakened forms of the virus. But this jab is known as a messenger RNA (mRNA) vaccine – which uses only the virus’s genetic code.

It is injected into the body, where it enters cells and tells them to create antigens, which are recognised by the immune system and prepare it to fight coronavirus.

– And how effective is it?

Analysis shows the vaccine can prevent 95% of people from getting Covid-19, including 94% in older age groups.

– Are there any logistical challenges?

The Pfizer/BioNTech vaccine needs to be stored at an ultra low temperature of between minus 70C and minus 80C.

Because of this, it can only be moved a few times, while the packs of doses – with 975 per pack – cannot be easily split.

However, Ben Osborn, Pfizer’s UK country manager, said that once the vaccine reaches the point of deployment, it can be stored for five days under normal refrigerated conditions of between 2C to 8C.

– What do we know about the jab’s safety? Any side effects?

A report by the developers said that the vaccine was well tolerated by the more than 43,000 participants involved, with no serious safety concerns observed.

Around 2% of those involved suffered a headache and fatigue, according to the data.

– And what have the regulators said about safety?

Dr June Raine, head of the Medicines and Healthcare products Regulatory Agency (MHRA), said “no corners have been cut” in assessing the jab’s safety.

“The safety of the public will always come first,” she told a briefing.

“This recommendation has only been given by the MHRA following the most rigorous scientific assessment of every piece of data so that it meets the required strict standards of safety, of effectiveness and of quality.”