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Coronavirus vaccines explained

Important update on the coronavirus vaccines and booster jabs:

The Joint Committee on Vaccination and Immunisation (JCVI) has approved an additional booster dose this spring for the most vulnerable people, in order to top up their protection levels to coronavirus. The extra spring booster dose will be available around six months after the last vaccine dose for:

  • adults aged 75 years and over
  • residents in care homes
  • people aged 12 years and over who are immunosuppressed, as defined in the COVID-19 healthcare guidance Green Book.

The types of vaccine offered for the spring booster dose will be either:

  • 50mcg Moderna (Spikevax) vaccine - for eligible adults aged 18 years and over


  • 30mcg Pfizer-BioNTech (Comirnaty) vaccine.

Is the vaccine safe?

Yes. The UK regulator and the Joint Committee on Vaccination and Immunisation (JCVI) (the independent experts that advise Government on all vaccines) have assessed all approved vaccines to be safe and able to offer a high level of protection against becoming severely unwell with coronavirus, including for older people.

While there are different vaccines available, no one will receive a vaccine that hasn’t been properly approved and shown to be safe.

Am I eligible for a booster vaccination?

All adults are currently eligible for a booster jab and the most vulnerable groups will also be eligible for an extra spring booster dose (6 months after their last booster jab). These eligible groups are:

  • adults aged 75 years and over
  • residents in care homes
  • individuals aged 12 years and over who are immunosuppressed, as defined in the COVID-19 healthcare guidance Green Book.

The JCVI have announced that autumn boosters are likely to be recommended to certain groups, too. We'll update this page with further details and timelines once they're announced.

When will I be offered a booster jab?

At present, if you're aged 18 or over and it's been at least 2 months since your second vaccine dose, you can book an appointment now – although your appointment won't be until 3 months after your second vaccine dose.

The NHS may contact you directly about booking your booster jab, or you can call 119 or visit the NHS website to book.

You can also visit a vaccine walk-in centre if it's been 3 months since your second vaccine. You can find your closest walk-in centre here.

Why do we need booster jabs?

Research has shown that the protection the vaccines provide starts to lessen as time goes on. With a new variant and rising cases, it's important that everyone who is eligible goes and gets their booster.

Which vaccine will I receive as my booster jab?

Most people will be offered a booster of Pfizer or Moderna vaccines, regardless of which vaccine you had for your first and second jabs.

Do I need to get my flu vaccine too?

Yes, it's important to get both your coronavirus booster and your flu jab this winter. They're different vaccinations that will help protect you against different viruses. 

It might be that you're offered both at the same time. This is perfectly safe and could be more convenient for you. 

We have more information specifically about flu vaccinations.

Getting your winter vaccines

This winter, it's important to get both your coronavirus booster jab and your flu jab. We have more information specifically about getting your flu vaccination.

Do I still need to isolate if I'm vaccinated?

While the vaccine does reduce your chances of catching coronavirus and getting severely ill, it is possible to still get coronavirus following two doses of the vaccine. So, if you get symptoms of coronavirus, or a positive test, we advise that you stay home and avoid contact with others, especially with vulnerable people.

How can I get the vaccine?

If you're aged 12 or over, you are eligible for the vaccine and can book online on the NHS website, or by calling 119 between 7am and 11pm. It's still not too late to get your first doses of the vaccine if you haven't already.

When booking your appointments, it's helpful to have your NHS number to hand – you can find it on letters from the NHS or on some medications. If you’re registered with a GP, you can still book without an NHS number. You’re also able to book an appointment on behalf of someone else.

If there isn’t a suitable appointment or venue available, then you should keep trying – more appointments and venues are added frequently.

If you’re housebound and unable to attend a vaccination centre or pharmacy site, then you should contact your GP practice – they should support you in receiving a vaccination at home.

What will happen at my appointment?

Make sure you arrive on time – but not too early – for your appointment to minimise contact between people getting vaccinated. Where possible, you should attend alone for social distancing measures, but if you need support in attending then one carer or family member can come with you.

Remember a face covering if you’re able to wear one and practise social distancing and good, regular handwashing to prevent the spread of infection.

When you attend your appointment, you’ll be asked:

  • How you’re feeling and whether you have any symptoms that would stop you from being able to have the vaccine.
  • About your medical history.
  • If you have any questions.
  • To consent to having the vaccine.

You’ll need to bring:

  • A face covering, unless you're exempt from wearing one.
  • Your booking reference number if your appointment is at a large vaccination centre.
  • Proof of your occupation if you’re a health or care worker.

What to expect:

  • All venues offering vaccines will have social distancing and other measures in place to keep you safe.
  • You’ll be given a leaflet about what to expect after your vaccination to take home with you.
  • You’ll be given a record card.

Keep your record card safe and make sure you attend your next appointment. It’s important to return for your second dose as this maximises long-term immunity.

The NHS has provided some information about what to expect at your appointment, including what to bring to it.

What are the side effects of the vaccine?

Each vaccine has gone through trials to ensure the risk of serious side effects is very low. However, as with other vaccines – such as the flu vaccine – there are some common side effects. These include:

  • A sore, 'heavy' arm where you had your injection.
  • Feeling tired.
  • A headache.
  • General achiness or mild flu-like symptoms.

A small proportion of people might experience swollen glands. If this happens to you, you're advised to take paracetamol.

If you do experience any of these side effects, they're likely to last no longer than a week. But if they get worse, or if you're concerned, you should call NHS 111 and explain your symptoms – let them know you've had a vaccination.

Any side effects you experience can also be reported to the MHRA Yellow Card Scheme by your doctor.

Serious reactions to vaccines are uncommon but can happen. People with an allergy to the ingredients of the vaccine should not receive it – however, those with other allergies (such as to food and other medicines) are able to. If you’re concerned, speak to your healthcare professional for further advice.

Will I need to prove I've had a vaccine?

The Government has announced that it will not be a legal requirement for you to prove your coronavirus or vaccination status. However, businesses can ask you for proof of a negative coronavirus test or vaccination in order to use their services. There have already been instances of people being asked to prove they've been vaccinated (in order to travel, for instance).

You can now display your coronavirus vaccine record on the NHS App or request a paper version by calling 119. But there are some things worth noting:

  • The NHS App is different to the NHS COVID-19 app which was being used for Test and Trace - a service that has now ended.
  • If you already have the NHS App, you should make sure you're using the most up to date version. 
  • It's recommended that you registered the NHS App at least two weeks before travelling.
  • The NHS App doesn't yet show coronavirus test results.
  • You can request a paper version of your vaccination record 5 days after your second vaccine – it can then take up to 5 days to arrive. 
  • You shouldn't ask your GP for proof of vaccination.

Different countries will have different entry requirements and for some destinations, you'll still need to be tested before entering, regardless of whether you've had your vaccine.  

I have another question about vaccines

How do vaccines work?

There are many types of vaccine, but the purpose of a vaccine is always the same: to train our immune system to respond to a germ as if it has seen it before and remembers how to tackle it. There are vaccines against illnesses caused by all sorts of germs, but as coronavirus is caused by a type of virus, we’ll focus on those here.

Vaccines teach our bodies to recognise antigens. This is the part of the virus that attaches to the cells in our body – something they need to do to replicate and cause an infection. Your body’s immune system produces antibodies that ‘match’ the antigens from a specific virus and prevent them from attaching to cells.

Traditional vaccines contain either a modified or weakened form of the virus, including the antigen. Some vaccines which use newer technology contain the genetic code for the virus’ antigen instead, so your body produces the antigen itself. Both methods have the same result: they prompt our immune system to make antibodies that ‘match’ the antigen.

After vaccination, if the virus gets into our body, our immune system remembers what to do and produces antibodies to fight it. This means the infection doesn’t get a chance to take hold and we are immune to the virus. Vaccination means we can stimulate this immunity without becoming unwell with the disease in the first place.

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How are vaccines developed?

There’s a careful process for developing vaccines to make sure they’re both safe and effective.

  1. Scientists identify the specific antigen to the virus that causes the disease, then develop a vaccine to trial.
  2. Initial tests take place to see if a vaccine is safe and will lead to immunity. These tests will take place ‘in vitro’ (in a group of cells which have been grown in a laboratory and aren’t part of an animal) or ‘in vivo’ (in animals).
  3. Then there are three stages of trials and at each of these stages, the vaccine is tested on more people. 
  4. The third stage of testing involves tens of thousands of volunteers. Some are randomly selected to receive the vaccine and some receive a placebo. Neither the scientists or volunteers know who gets selected for each.
  5. Volunteers are then monitored closely to determine whether people catch the disease and if there are any side effects. Monitoring continues to determine how long immunity lasts.
  6. When these stages are completed, the vaccine must then be licensed.

Wherever a vaccine is developed, it must be granted approval by the Medicines and Healthcare products Regulatory Agency (MHRA) if it's to be used in the UK. They examine the available information about the vaccine, how well it works and whether it’s safe before giving approval. Once approved and licensed, the vaccine needs to be produced in large enough quantities before finally being given to the population.

The coronavirus vaccines have all been through these stages before being approved for use.

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How have the coronavirus vaccines been developed so quickly?

Developing a vaccine often takes some time. This is usually because research and pharmaceutical companies can’t commit to funding the whole process. There are often long gaps between phases while organisations wait for funding before moving to the next stage. Even when a vaccine is approved, it takes some time for pharmaceutical companies to set up manufacturing and produce the vaccine in the quantities needed for public use.

As the coronavirus pandemic has had such an impact globally, researchers and pharmaceutical companies worked together to reduce the amount of time spent waiting between the phases of development.

Funding and approval for these vaccines was made a priority. Governments around the world ‘pre-ordered’ doses which meant pharmaceutical companies were able to set up manufacturing for vaccines earlier than usual.

The NHS prepared a vaccination programme so that it could start vaccinating people as soon as vaccines were approved and available.

While this collaborative approach means vaccines were made available sooner, it doesn’t mean any shortcuts were taken. Each vaccine approved has been through all the essential stages in its development.

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Should I get a vaccine?

Whether or not you get a vaccine is an individual decision. The vaccine isn't compulsory.

However, as with making any decision, there are things worth considering:

  • Being vaccinated means you're much less likely to become ill with coronavirus.
  • Most of the population will have to be vaccinated for this pandemic to come to an end.
  • Any vaccine offered to you has been licensed and approved and has gone through all the necessary stages of development to make it safe and effective.
  • Your healthcare professional is there to answer any questions or worries you might have about the vaccine.

It’s recommended that pregnant women should only receive the vaccine in certain circumstances. Children shouldn't get the vaccine at the moment, either. This is simply because it hasn't yet been tested on these groups.

If you have concerns based on specific medications or medical conditions, here are some links which may help answer your questions:

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I've had coronavirus. Do I still need to get a vaccine?

While your body may have built up some natural immunity to coronavirus if you’ve already had it, we don’t know for certain how long this immunity lasts or how well it protects you from catching it again.

This natural immunity from having an illness doesn’t usually last as long as the immunity given by a vaccine, so it’s recommended that if you’ve had coronavirus you do still get a vaccine.

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Where can I get reliable information about the vaccine?

At Age UK, we get all of our information from reputable sources including the NHS, academic experts, scientific publications, pharmaceutical companies, the World Health Organisation, and the organisation that approves the vaccines: the Medicines and Healthcare products Regulatory Agency (MHRA).

But there's a lot of misinformation out there. So how do you know what you can believe?

Do I know where this information has come from?

If the person you’re talking to, the social media post you’re reading, or the YouTube video you’re watching doesn’t say where they’ve found the information they’re sharing, it’s worth being sceptical.

We also know there is false information out there which has been created deliberately to worry or upset people. If you see something unnerving, run through the rest of this checklist to see if it is likely to be true.

Is it from a trusted source?

Is the information from a trusted news source that you are familiar with? There are lots of people claiming to be experts speaking about vaccines, but it may be hard to tell whether they are as knowledgeable as they say they are.

Who else is saying the same thing?

If you’ve found information that looks like it could be legitimate, but you aren’t sure, see if you can find it from other reputable and trusted sources. It is unlikely that only one source has a true story about coronavirus.

Is this new or old information?

This is a quick-changing area and researchers are improving knowledge about coronavirus and the vaccines all the time. What may have been thought to be true a month ago may have been improved upon, disproven, or understood better by now.

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What about reports from other countries on the side effects and usage of the Oxford/AstraZeneca vaccine?

There have been reports of other countries pausing their rollout of the Oxford/AstraZeneca vaccine to certain groups. The MHRA (Medicines and Healthcare products Regulatory Agency) in the UK, the European equivalent, the European Medicines Agency (EMA), and the World Health Organisation (WHO), are all confident of the safety and effectiveness of the Oxford/AstraZeneca vaccine and agree that the benefits outweigh any risks.

Millions of people have received the Oxford/AstraZeneca vaccine. A small number of people have developed health conditions after vaccination. There is substantial evidence of the benefits of the vaccine in preventing illness from coronavirus. The MHRA, EMA and WHO continue to closely monitor all coronavirus vaccines.

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Last updated: May 24 2022

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