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A guide to the COVID-19 booster vaccination for adults

What is coronavirus or COVID-19?

COVID-19 is a very infectious respiratory disease caused by the SARS-CoV-2 virus and is more serious in older people and those with certain health conditions.

Why do some people need a COVID-19 booster vaccination?

Like some other vaccines, levels of protection may begin to wane over time. This booster dose will help extend the protection you gained from your first two doses and give you longer term protection.

The booster will help to reduce the risk of you needing admission to hospital due to COVID-19 infection this winter.

Who will be offered a COVID-19 booster vaccine?

All adults aged over 18, and those aged over 16 years who are in an increased risk group (including health and social care workers),will be offered a booster dose of COVID-19 vaccine.

The booster will first be offered to those at higher risk of catching COVID-19 and likely to suffer serious complications of the infection which includes older adults and those with a health condition or in a group at greater risk from COVID-19.

When will the COVID-19 booster vaccine be given?

The booster can be offered at least three months after your last dose. Like your previous doses, the vaccine will be given in your upper arm. Protection against severe disease from the first two doses seems to decline very slowly but the booster dose should help to extend your protection into the next year.

How will I get my vaccination?

The NHS will be in contact with you to let you know when and where to have the vaccine. It’s important to attend your appointment when you are invited. If you can’t attend please let the booking team know so your appointment can be given to someone else. Contact details are available on your appointment letter.

Which vaccine will you be offered?

You will be offered the right vaccine for you which may be the same ordifferent from the vaccines that you had before. These vaccines have been given to millions of people in the UK – they are safe and recommended for use as boosters.

Will I experience any side effects?

As with your previous doses, common side effects are the same for all COVID-19 vaccines used in the UK, and include:

  • having a painful, heavy feeling and tenderness in the arm where you had your injection for several days after the vaccine
  • feeling tired
  • headache
  • general aches or mild flu like symptoms

A mild fever may occur for two to three days but a high temperature is unusual and may indicate you have COVID-19 or another infection. You can take the normal dose of paracetamol (follow the advice in the packaging) and rest to help you feel better. Do not exceed the normal dose. These symptoms normally last less than a week. If your symptoms seem to get worse or if you are concerned, call NHS 111 Wales on 111 or your GP surgery. If 111 is not available in your area, call 0845 46 47. Calls to NHS 111 Wales are free from landlines and mobiles. Calls to 0845 46 47 cost 2p per minute plus your telephone provider’s usual access charge.

Serious side effects

Worldwide, there have also been recent, very rare cases of inflammation of the heart called myocarditis or pericarditis reported after Pfizer and Moderna COVID-19 vaccines.

These cases have been seen mostly in younger men within several days after vaccination. Most of these people recovered and felt better following rest and simple treatments.

You should seek medical advice urgently if, after vaccination, you experience:

  • chest pain
  • shortness of breath
  • feelings of having a fast-beating, fluttering or pounding heart

Who shouldn’t have a COVID-19 booster vaccination?

There are very few people who should not have a booster. If you had serious side effects after any previous dose you may be advised to avoid or delay further vaccination. You should discuss this with your doctor or specialist. You can report any side effects online or via the Yellow Card app.

What should I do if I have had COVID-19 already?

You still need to have a booster vaccine even if you’ve already been infected with COVID-19.

If you’ve recently tested positive for coronavirus, you should wait until 4 weeks after COVID-19 infection before getting your booster, even if you had no symptoms.

Further information and patient leaflets can be found at:

Can you still catch COVID-19 after having the vaccine?

The COVID-19 vaccination will reduce the chance of you suffering from COVID-19. It may take a few days for your body to build up some protection from the booster.

Like all medicines, no vaccine is completely effective – some people may still get COVID-19 despite having a vaccination, but this should be less severe.

If you have not had the first vaccinations

If you have not yet had either of your first two doses of the vaccine you should have them as soon as possible.

You will still need the booster but the timing of it will depend on when you had your first two doses. If you are also eligible for a flu vaccine you can receive this at the same time as your booster vaccine or at any time before or after.

More information on flu vaccination is available here: .

More information

You can find out more information about COVID-19 vaccines, including their contents and possible side effects at:

Further information and patient leaflets can be found at:

You can report suspected side effects online at or by downloading the Yellow Card app.

To find out how the NHS uses your information, visit:

For other formats of this leaflet visit: