Covid-19 vaccine: everything you need to know
Coronavirus frequently asked questions
Updated 19 January 2023
Millions of people have had a Covid vaccine since the pandemic started three years ago. It's thought that the vaccines have saved countless lives around the world.
The majority of people in the UK have now had their first two jabs, and eligible people are receiving boosters.
On this page you’ll find answers to frequently asked questions about the Coronavirus (Covid-19) vaccine, and links to further information from trusted, reliable resources.
Looking for quick vaccine facts translated? Visit our Coronavirus vaccine hub page.
Pregnancy and fertility
What are Covid-19 variants?
All viruses change over time. Most changes have little to no impact on the virus’ properties. However, some changes may affect the virus’ properties, such as how easily it spreads, the associated disease severity, the performance of vaccines, therapeutic medicines, diagnostic tools or other public health and social measures.
In 2022, Omicron was the world's most dominant variant. While the variant spread faster and to more people, it generally causes milder illness in vaccinated people. The latest variant is a version of Omicron called XBB.1.5. However, it's not thought to cause more severe illness.
Do I need a Covid-19 booster vaccine?
Protection from the Covid-19 vaccines doesn’t last forever in your body. Like many other vaccines, the Covid-19 vaccines will reduce over time.
Booster vaccines are being offered to help extend your protection against Covid-19 to help keep you and your loved ones safer for longer.
Several studies into the Covid-19 vaccines suggest that while protection against severe disease remains high in most groups at least 5-6 months after the second dose of a Covid-19 vaccine, there is evidence that protection against infection and symptomatic disease will decrease.
Who is eligible for a Covid-19 booster vaccine?
Covid-19 boosters are currently being offered to all adults over 18 and people aged 16 over who are most at risk of Covid-19.
Like some other vaccines, levels of protection may begin to reduce over time. This booster dose will help extend the protection you gained from your first 2 doses.
It will also give you longer term protection and reduce the risk of you needing admission to hospital due to Covid-19 infection this winter.
Why have some people been offered a third primary dose rather than a booster?
Some people with compromised immune systems or who are receiving treatment which may affect their immune system, are being offered a ‘third primary dose’ of a Covid-19 vaccine.
This is because their health conditions or medical treatment may prevent their immune system from producing a good response to Covid-19 vaccination.
A third primary dose will be offered to people identified as being at risk of not producing a good immune response 8 weeks after their second dose.
What's the difference between a third dose and a booster vaccine?
The main difference between a third dose and booster vaccine is in who is eligible for one, and when they are given. While booster doses are given 6 months after the first two, third doses are given at least 8 weeks after the 2nd dose.
Third doses are being offered to people 12 and over who have problems with their immune system or are receiving treatment (such as chemotherapy or high doses of steroids) which may affect their immune system. They may not have produced as good an immune response (their body may have a harder time recognising the signs of immunisation and producing antibodies) to the Covid-19 vaccine after the first two doses as someone who’s immune system is working normally.
This could mean that after only two doses of the vaccine, their protection may still be lower, so they are offered a third dose to extend their protection.
The timing of the third dose should be decided by the specialist involved in the treatment for their immune condition or other therapy that affects it.
When will I be offered a Covid-19 booster vaccine?
If you are eligible, you will be offered a Covid-19 booster vaccine at least 3 months (91 days) after your 2nd dose.
Which Covid-19 vaccine will I receive for the booster dose?
If eligible, you will be given a booster dose of either Pfizer or Moderna vaccine. These vaccines have already been given to millions of people in the UK.
You will be offered the right vaccine for you which may be the same or different from the vaccines that you had before.
How do I book a Covid-19 booster vaccine?
Once eligible, there are three ways you can book a Covid-19 booster vaccine:
- Wait to be contacted by your local GP, or NHS service, and book directly with them.
If you have been offered a booster vaccination because you are considered high risk, when visiting a walk-in centre, please bring your booster invitation letter, or a letter from your doctor explaining your health condition.
If you are a frontline health or social worker, you’ll need to bring proof of your employment to your walk-in booster appointment, such as your workplace photo ID.
You must wait until 3 months (91 days) between the date of your second dose before going for your booster vaccine.
How long do I have to wait before I can book a Covid-19 booster vaccine after testing positive for Covid-19?
If you have tested positive for Covid-19 and are eligible for a Covid-19 booster vaccine, you’ll need to wait the following times before you can get a Covid-19 booster vaccine:
- 4 weeks (28 days) after testing positive, if you're over 18,
- 4 weeks (28 days) after testing positive, if you're 12-17 and considered high risk
- 12 weeks (94 days) after testing positive if you're under 18, and not considered high risk.
Is it safe to have the flu and Covid-19 booster vaccine at the same time?
Yes. If you are offered both the flu and Covid-19 booster vaccines, it is safe to have them at the same time, according to the NHS.
How do the Covid-19 vaccines work?
The Covid-19 vaccines work in the same way all vaccines do: by sending a signal to our immune system to create the antibodies that will fight the virus. Once your immune system knows how to fight disease, it can protect you in the event of exposure.
Getting a vaccine is a much faster and safer way for your immune system to learn how to create the antibodies required to protect you from a disease, rather than catching the disease or virus itself.
If enough people are vaccinated, it’s harder for the virus to spread to people who are unable to have vaccines. For example, people who are ill or have a weakened immune system. This is called ‘herd immunity’.
What are the Covid-19 vaccines?
The two vaccines used in the UK are:
- The Pfizer/BioNTech vaccine, also known as the Pfizer vaccine, BioNTech vaccine or by its trade name 'Comirnaty', which was rolled out in January 2021.
- The Moderna vaccine, also known by its trade name 'Spikevax', became available in April 2021.
The AstraZeneca vaccine is no longer used in the UK. Evidence shows that mRNA vaccines, Pfizer and Moderna, are more effective at boosting protection from Covid-19, so these vaccines are being recommended for primary courses and booster programme.
The Novavax vaccine has also been approved for people who can’t have mRNA-based vaccines due to allergies.
What's in the Covid-19 vaccines? (vaccine ingredients)
The ingredients in the Covid-19 vaccines are very similar to the ingredients found in childhood vaccines, with many commonly found naturally in the human body, such as salt and water. The active vaccine ingredients make up a few thousandths of a gram - this is what actively prepares the body to fight the virus.
The Covid-19 vaccines do not contain chimpanzee cells, foetal tissues, animal products or eggs, and are suitable for vegans and vegetarians.
What's in the Pfizer/BioNTech vaccine?
The Pfizer vaccine is an mRNA vaccine (messenger RNA), delivered in two doses (0.3 ml each). The active ingredient (highly purified single-stranded, 5’-capped messenger RNA ) sends instructions to the body’s cells to make specific viral proteins that can be recognised by the immune system to fight the Covid-19 virus. The Pfizer vaccine does not contain any live virus, so can't give you Covid-19.
What's in the Moderna vaccine?
The Moderna vaccine works in exactly the same way as the Pfizer vaccine. It's an mRNA vaccine, delivered in two doses (0.5ml each).
I’m allergic to a number of medications, including penicillin, can I still have the vaccine?
None of the Covid-19 vaccines contain penicillin.
Both the Pfizer/BioNTech and Moderna vaccines contain a compound called Polyethylene glycol (PEG) – used to stabilise the lipid particles in the vaccine, and the Oxford/AstraZeneca vaccine contains Polysorbate-80 (an emulsifier which helps to stabilise the vaccine).
Both of these compounds are closely related, and are found in many other medications.
If you have a known severe allergy or anaphylactic reaction to either of these compounds, or have had an unexplained severe reaction in the past you should discuss vaccination with your GP or health professional.
What are the Covid-19 vaccine side effects?
The most common Covid-19 vaccine side effects include:
- a sore arm where the needle went in
- tenderness or aching in the arm
- tiredness, headaches, general aches and mild flu like symptoms, for some.
Side effect symptoms are generally mild and will usually last one to two days. Some people can experience them for longer - up to one week.
Everyone is different, so the side effects you might experience (if you get any at all) will depend on which vaccine you receive, whether it’s the first or second dose, and you as an individual.
All Covid-19 vaccines approved for use in the UK with authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA) are considered safe, and will continue to be monitored for safety and effectiveness.
When to seek urgent medical advice
If you experience any of the following from around four days to four weeks after vaccination you should seek medical advice urgently:
- a new, severe headache which is not helped by usual painkillers or is getting worse
- an unusual headache which seems worse when lying down or bending over or may be accompanied by
- blurred vision, nausea and vomiting
- difficulty with your speech
- weakness, drowsiness or seizures
- new, unexplained pinprick bruising or bleeding
- shortness of breath, chest pain, leg swelling or persistent abdominal pain.
Reports of risk of heart inflammation with Pfizer and Moderna vaccines
There have been extremely rare reports of inflammation of the heart reported after Covid-19 vaccination with Moderna and Pfizer/BioNTech COVID-19 vaccines. Most people who had this recovered following rest and simple treatments.
It is not yet clear if it was caused by the vaccines, and the MHRA is continuing to investigate both the occurrences and any risk factors. They have occurred most frequently in younger males shortly after the second dose of the vaccine.
Anyone who has any of these symptoms within a few days of being vaccinated should seek urgent medical advice:
- chest pain
- shortness of breath
- a fast beating, fluttering or pounding heart (palpitations)
What should you do if you're experiencing Covid-19 vaccine side effects?
Mild Covid-19 vaccine side effects are common but not everyone will get them. Side effects usually last one to three days, but can last up to one week.
If you do experience symptoms, it’s still important to have your second dose. The second dose of the vaccine will give you the best protection against the virus.
If you are experiencing side effects:
- Rest until you feel better.
- Take the normal dose of paracetamol (follow the advice on the packaging) to help ease mild symptoms.
- If your symptoms seem to get worse or if you are concerned, call NHS 111.
- If you do seek advice from a doctor or nurse, let them know you’ve been vaccinated and show them your vaccination card so that they can assess you properly.
You can also report suspected side effects of vaccines and medicines online through the Yellow Card scheme.
Does the Covid-19 vaccine affect menstrual cycles?
An evaluation into reports of menstrual disorders following the Covid-19 vaccines found that the number of reports of menstrual disorders and vaginal bleeding were low in relation to both the number of people who have received Covid-19 vaccines to date, and therefore did not support a link between changes to menstrual periods, related symptoms and Covid-19 vaccines.
The MHRA continues to closely review reports of suspected side effects of menstrual disorders and unexpected vaginal bleeding, and anyone experiencing unusual changes to their periods following Covid-19 vaccination, should contact their doctor.
Does the Covid-19 vaccine affect fertility?
There is no evidence that the Covid-19 vaccines have any effect on male or female fertility, and there is no need to avoid pregnancy after vaccination.
Can you have the Covid-19 vaccine if you're pregnant or breastfeeding?
If you're pregnant, you should get vaccinated as soon as possible. There is growing evidence showing that women who are pregnant are at increased risk of serious consequences from Covid-19 and should be considered a clinical risk group within the Covid-19 vaccination programme.
It is currently recommended for you to have the Pfizer/BioNTech or Moderna vaccine if you’re pregnant (because they've been more widely used during pregnancy in other countries).
If you are worried about being vaccinated whilst pregnant or breastfeeding, speak to your healthcare professional (GP or midwife) before you have the vaccination. They will discuss the benefits and risks with you.
The vaccine cannot give you or your baby Covid-19.You can also have the Covid-19 vaccine if you're breastfeeding.
Can children get the Covid-19 vaccines?
All children aged 12 to 17 (including those who turn 12 on the date of vaccination) are now eligible for a 1st and 2nd dose of a Covid-19 vaccine.
Children aged 12 to 15 will be offered a Covid-19 vaccine at school, or through the national booking system to get a vaccine at their vaccine centre.
For children aged 12 to 15 years, consent will be sought by the School Age Immunisation Service (SAIS) provider, or by the healthcare professional at a vaccination centre from the parent or person with parental responsibility in the same way as any other school vaccination programme.
Parents and guardians will get a letter with information about when the vaccine will be offered. Children under 12 are at this time unable to be routinely vaccinated against Covid-19 in the UK.
How many people have had the Covid-19 vaccine?
As of September 2022, more than 53,813,491 people in the UK have received their first Covid-19 vaccine dose, and 50,762,968 have had their second dose. Over 40,373,987have now received their third or booster dose. In total, 151,248,820 vaccines have been given in the UK.
Visit Gov.UK for daily updates of the number of people in the UK who have received their Covid-19 vaccine.
All children and adults in the UK (aged 12 and over) are now eligible to receive Covid-19 vaccination.
Are the Covid-19 vaccines safe?
Yes, the coronavirus vaccines are safe and effective, and will give you the best protection against Covid-19. While they were developed far quicker than the average 8-10 years required for previous vaccines, this is because of the massive effort by researchers, the money invested by governments, and the willingness of volunteers to trial them.
All vaccines approved were rigorously tested before being approved, and have met the strict standards of safety, quality and effectiveness set out by the MHRA.
Vaccines are the most effective way to prevent infectious diseases and save up to 3 million lives worldwide every year. Thanks to vaccine roll-outs in the past, diseases like smallpox, polio and tetanus no longer exist or are very rare.
How effective is the Covid-19 vaccine?
The Pfizer and Moderna vaccines have been updated to better target the Omicron variant. They’re given alongside the original vaccines. These updated ‘bivalent’ or ‘combined’ vaccines include a half dose of the original vaccine, and a half-dose of an updated formula, which is designed to better target the Omicron variant.
Both the original and updated vaccines are shown to offer a good boost in protection - between 70 – 90% - so whichever vaccine you are offered will help to top-up your protection.
How soon after getting the Covid-19 vaccine are you protected?
You are partially protected from Covid-19 three to four weeks after receiving your first Covid-19 vaccine. But it’s important to receive 2 doses for stronger and longer-lasting protection.
Can I get Covid-19 again after 90 days of testing positive?
Yes, you can. If you test positive for Covid-19 again, 90 days after testing positive using a PCR or rapid lateral flow test, it should be considered a new infection.
The 90-day period is from the initial onset of symptoms or from confirmation of a positive test result, if asymptomatic.
Yes, you can. While Covid-19 vaccines provide a high level of protection against severe disease, hospitalisation and death, you can still get Covid-19 and pass it on to others, even if you have been fully vaccinated, although studies have shown that the chances of spreading the disease do reduce if someone has been vaccinated
Can I drink alcohol after having the Covid-19 vaccine?
While there is no published data on the effect of drinking alcohol after having the Covid-19 vaccine ‘there is some evidence that drinking alcohol, particularly sustained heavy drinking, adversely affects the immune system, and may impair the body’s ability to build immunity in response to vaccines’.
Can I get the Covid-19 vaccine if I have a cold?
You can get a Covid-19 vaccine if your cold-like symptoms are mild. If you are very unwell and experiencing Covid-19 symptoms, the NHS advises to wait until you are recovered before getting a Covid-19 vaccine.
If you have tested positive for Covid-19, wait 28 days (or 12 weeks for under 18s) after testing positive, or after your symptoms started, before getting your Covid-19 vaccine. If unsure, please contact 119 or your local GP.
How long does it take for Covid-19 symptoms to appear?
Covid-19 symptoms may appear 2-14 days after exposure to the virus.
The most common Covid-19 symptoms are:
- a new continuous cough
- a high temperature
- a loss of or change in your normal sense of taste or smell.
About 1 in 3 people with Covid-19 do not have symptoms, but can still infect others.
If you, or someone you know might have Covid-19, the advice is to stay at home and arrange to have a Covid test.
- If you’re concerned about symptoms or are unsure of what to do, get help from NHS 111 online
How long do Covid-19 symptoms last?
Covid-19 symptoms can last for several weeks or months after the infection is gone – this is called ‘long Covid’. However, most people will make a full recovery within 12 weeks.
Common long Covid-19 symptoms include:
- a high temperature and cough
- tinnitus, earaches
- extreme tiredness
- shortness of breath chest pain or tightness
- problems with memory and concentration
- difficulty sleeping (insomnia)
- heart palpitations and more.
Which vaccine will I get?
Which vaccine you get will mainly depend on availability, but you will only receive a vaccine that has been officially approved. Some people may be advised to have a specific vaccine due to age, medical conditions or allergies. The only vaccines currently available in the UK are Pfizer/BioNTech.
Which vaccine is the best?
Experts agree - the best vaccine is the one that’s offered to you first. All vaccines available in the UK are regularly monitored and have been thoroughly tested. Some people may be advised to have a specific vaccine due to age, medical conditions or allergies.
Is the vaccine permitted in my religious community?
Many religious communities openly support the Covid-19 vaccine, including The Muslim Council of Britain, who confirmed that all approved Covid-19 vaccines are safe to take, with all versions approved by The British Islamic Medical Association.
What to expect at your Covid-19 vaccine appointment
Your vaccine appointment will take place at your GP surgery, local hospital, pharmacy, or nearest mass vaccination centre. There are also mobile ‘pop-up- vaccination services that are visiting certain communities. Unless exempt, you will need to wear a face covering to your appointment.
Here are a few things to expect during your first Covid-19 vaccine appointment:
- Your appointment could last up to 30-45 minutes (but many are much quicker). If your appointment is at a vaccination centre, you'll be asked for your booking reference number on arrival. If you can, bring along your NHS number with you.
- Before receiving the Covid-19 vaccine you'll be asked questions about your medical history. It’s important to tell the vaccination staff if you have any serious medical problems, allergies or if you are pregnant.
- You will then be given an injection of the vaccine into your upper arm, so try and wear something loose, or that can be easily lifted up to allow the vaccinators to get to your arm.
- After you've had your Covid-19 vaccine, you may be asked to wait (between 15-30 minutes), if you have previous history of a reaction to vaccines, or severe allergies to other medicines as a precaution in the unlikely event that you have a severe reaction. Anyone receiving the vaccination should not drive for 15 minutes afterwards.
- Before you leave your appointment, you'll receive a vaccination leaflet to take home with information about the Covid-19 vaccine you received, and what to expect after your vaccination.
What should you do after you get your first Covid-19 vaccine?
All of the vaccines in use in the UK require two doses to provide the best protection. After your first dose, your next appointment should be no sooner than 8 weeks after your first appointment (this may be sooner if you have problems with, or are due to have treatment for your immune system).
If you have not booked your coronavirus vaccine appointment and you have received an invitation, you can book your vaccine appointment on the NHS website. You may need your NHS reference number.
If you already have Covid-19 vaccination appointments booked, you can also view, cancel or change your appointment on the NHS website. If you haven’t received an invitation, but think you might be eligible, speak to your GP, or ring 119.
Do I need a vaccine, if I've already had Covid-19?
If you’ve already had the illness, your body creates antibodies to fight off future infections. However, the jury is still out on exactly how much protection you receive or how long these antibodies last following infection. Vaccination is the best way of protecting yourself and others against the virus in the long term.