Coronavirus (COVID-19): vaccine safety
All COVID-19 vaccines approved for use in the UK have met strict standards of safety, quality and effectiveness set out by the independent Medicines and Healthcare products Regulatory Agency (MHRA). They must go through all the clinical trials and safety checks all other licensed medicines go through.
Four COVID-19 vaccines have been approved for use in the UK. Further information, including ingredients, can be found at these links:
The first three vaccines are in use in Northern Ireland. The Janssen vaccine is expected to be available in the UK later this year.
Other vaccines are also being developed. They will only become available once they have been thoroughly tested to make sure they are safe and effective.
Once the MHRA has approved a vaccine for use, it is closely monitored to continue to make sure it is safe and effective.
Developing COVID-19 vaccines
Vaccine research does not take a long time. It’s all the steps beforehand, like getting funding and approval, that takes the time.
COVID-19 vaccines have been developed at speed because the UK Government has funded trials, to get them up and running quickly.
The MHRA and Health Research Authority have also sped up the administrative process of approval. Processes have been streamlined and now run in parallel to reduce the time for delivery of the clinical trials.
The length of the trials themselves has not been shortened, and the usual safety measures remain in place.
New technology has also helped, enabling vaccines to be manufactured quickly. Vaccines are being produced in advance meaning that they are available as soon as they are approved.
Advice if you are pregnant or breastfeeding
Although clinical trials on the use of COVID-19 vaccines during pregnancy are not advanced, the available data does not indicate any harm to pregnancy.
If you are pregnant you will be able to receive a COVID-19 vaccine at the same time as the rest of the population based on your age and clinical risk group.
You may wish to discuss having it with your doctor or midwife.
If you decide to have a COVID-19 vaccine, tell the vaccination team that you are pregnant so that this can be recorded.
There have been no specific safety concerns identified with any brand of COVID-19 vaccines in relation to pregnancy. Pfizer-BioNTech and Moderna vaccines are the preferred vaccines for pregnant women of any age, because of more extensive experience of their use in pregnancy.
However, if you are pregnant and have had the first dose of the AstraZeneca vaccine, you should get a second dose of the same vaccine.
There is no known risk associated with any current COVID-19 vaccines whilst breastfeeding.
The Joint Committee on Vaccination and Immunisation (JCVI) advises that breastfeeding women may be offered any suitable COVID-19 vaccine. Talk to your doctor or midwife if you have any concerns.
For more information see:
COVID-19 vaccines and fertility
There is no need to avoid pregnancy after COVID-19 vaccination and there is no evidence to suggest that COVID-19 vaccines will affect the fertility of women or men.
More information is available on a document created by the British Fertility Society and Association of Reproductive and Clinical Scientists:
COVID-19 vaccine side effects
Like all medicines, the COVID-19 vaccine can cause side effects, but not everyone gets them.
Any side effects of the COVID-19 vaccine are usually mild and should not last longer than a week, such as:
- a sore arm where the needle went in
- feeling tired
- a headache
- feeling achy
- feeling or being sick
You may get a high temperature or feel hot or shivery one or two days after having your vaccination. You can take painkillers, such as paracetamol, if you need to. If your symptoms get worse or you are worried, call your GP.
If you have a high temperature that lasts longer than two days, a new, continuous cough or a loss or change to your sense of smell or taste you may have COVID-19. Stay at home and get a test.
You cannot catch COVID-19 from the vaccine, but you may have caught it just before or after your vaccination.
Report a side effect at:
Tell the vaccination team before you are vaccinated if you've ever had a serious allergic reaction.
You should not have the COVID-19 vaccine if you have ever had a serious allergic reaction (including anaphylaxis) to:
- a previous dose of the same vaccine
- any of the ingredients in the vaccine
Serious allergic reactions are rare. If you do have a reaction to the vaccine, it usually happens in minutes. Staff giving the vaccine are trained to deal with allergic reactions and can treat them immediately.
Reports of extremely rare blood clots
The MHRA is carrying out a detailed review of reports of an extremely rare blood clotting problem affecting a small number of people who have had the AstraZeneca vaccine.
The problem can also happen in people who have not been vaccinated and it's not yet clear why it affects some people.
The COVID-19 vaccine can help stop you getting seriously ill or dying from coronavirus. For people aged 40 or over and those with other health conditions, the benefits of being vaccinated with the AstraZeneca vaccine outweigh any risk of clotting problems.
For people under 40 without other health conditions, it's preferable for you to have the Pfizer-BioNTech or Moderna vaccine instead of the AstraZeneca vaccine.
For further information, see:
Seek medical advice urgently from your GP or emergency department if you get any of these symptoms starting from around four days to four weeks after being vaccinated:
- a severe headache that is not relieved with painkillers or is getting worse
- a headache that feels worse when you lie down or bend over
- a headache that's unusual for you and occurs with blurred vision, feeling or being sick, problems speaking, weakness, drowsiness or seizures (fits)
- a rash that looks like small bruises or bleeding under the skin
- shortness of breath, chest pain, leg swelling or persistent abdominal (tummy) pain
You can find more information on COVID-19 vaccine safety on the Public Health Agency’s website at: