The Covid-19 vaccine rollout the UK is entering its next phase, after a jab has been offered to everyone in the top four priority groups.

Two vaccines – developed by Pfizer-BioNTech and Oxford-AstraZeneca – are being used to protect against serious illness and death from Covid-19. A third, from Moderna, has been approved and will be used when stocks become available in the spring.

Vaccines are given to the most vulnerable first. A list of high-priority groups – covering up to 99% of those most at risk of dying – is being followed.

If you’re 70 or over in England and haven’t yet been vaccinated, you are now being asked to contact the NHS to book an appointment online or by calling 119 free of charge.

Most NHS frontline staff, care home residents and workers, and over 70s have been vaccinated. Some areas are now inviting over 60s, as well as some over 16s with certain health conditions, adult carers of disabled people with these conditions and younger adults in care homes.

All four nations of the UK follow these priorities, but the roll-out varies between England, Scotland, Wales and Northern Ireland.

The aim is to vaccinate over-50s by the start of May.

Police officers and teachers will be vaccinated after the most vulnerable groups – probably from late spring.

Any change to priorities will be decided by the Joint Committee on Vaccination and Immunisation (JCVI).

The Oxford vaccine offers a similar level of good protection against the ‘Kent’ variant now dominant in the UK as it does against the original virus.

Early research on other vaccines, including Pfizer’s, suggest they also protect against this new form of coronavirus.

All have been shown to be effective at preventing people from becoming seriously ill and dying from Covid-19.

But there are concerns that Covid vaccines may not work as well against other variants with a mutation called E484K. This has been found in variants first spotted in South Africa and Brazil, and in some UK variants too.

Nonetheless, the World Health Organization has recommended that the Oxford vaccine, which is seen as suitable for rollout around the world, should still be used in countries where these variants are present – as well as in all adults over 18.

People should still feel confident about getting vaccinated, the government’s deputy chief medical officer, Jonathan Van Tam, has said.

There is no sign that the South Africa variant will become dominant in the UK and the “immediate threat” is from the Kent variant, he said. There is “plenty of evidence” the vaccines are effective against that, Prof Van Tam added.

New versions of the vaccines are already being worked on and the plan is to have them ready by the autumn.

They are likely to be offered as a routine booster against Covid.

The approved vaccines require two doses to provide the best protection against Covid.

In the UK, people were initially told they would get a second dose three to four weeks after the first. But to ensure as many people as possible were protected in the shortest time possible, the UK’s chief medical officers extended the gap to 12 weeks.

This approach for the Oxford vaccine is now backed by the World Health Organization which says giving two doses 8-12 weeks apart increased the vaccine’s effectiveness and provided greater protection.

A recent study found the Oxford-AstraZeneca vaccine remained 76% effective during the three months after the first dose. There was also evidence the Oxford vaccine could reduce the spread of the virus.

Some doctors are worried that a long gap between doses of the Pfizer vaccine will make it less effective.

You’ll be invited to book an appointment as soon as it’s your turn, by phone or letter.

Thousands of vaccination sites are operating:

The official guidance says everyone should get the same vaccine for both doses.

In very rare circumstances – if only one vaccine is available, or it’s not known which was given for the first dose – a different vaccine can be used.

But that could change. A UK trial is investigating whether mixing vaccines could offer better protection than two doses of the same one.

The UK has ordered seven vaccines and expects to receive 407 million doses – more than enough for every adult to receive two.

The aim is to vaccinate as many people as possible over the age of 18.

The vaccines have not been tested in children so they won’t receive them until more research has been carried out.

Getting a Covid vaccine is not compulsory because experts say this wouldn’t help create public confidence.

Experts have not specified that any one group should get a particular vaccine.

A very small number of people have experienced a severe allergic reaction – known as anaphylaxis – when vaccinated with the Pfizer BioNTech vaccine.

The UK regulator says anyone with a history of severe reactions to food, insect bites, or a drug or vaccine, can safely receive the vaccines as long as they are not allergic to any ingredients.

You should discuss any serious allergies with your healthcare professional before being vaccinated.

Most people will not be affected in any way, although mild side-effects are possible.

Vaccination should only be considered for pregnant women when the potential benefits outweigh any potential risks.

This may be where the risk of catching coronavirus is high, or where underlying health conditions mean a high risk of Covid complications.

There are no specific safety concerns with the vaccines – but they were not tested on pregnant women.

Women who are breastfeeding can be given either vaccine.

No – this vaccine is being rolled out free to people via the NHS. You can’t jump the queue by paying.