Are the Covid-19 vaccines safe?

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26 January 2021

Read our guide to the vaccine development process and recommendations for its use

The Medicines and Healthcare products Regulatory Agency (MHRA), responsible for ensuring the safety of medicines and medical devices in the UK, has approved three Covid-19 vaccines: Pfizer/BioNTech, Oxford/AstraZeneca and Moderna.

The three vaccines are effective and safe with adverse reactions that, when present, are usually mild and resolved within a few days after administration.

The most common adverse effects include:

  • Injection-site pain and swelling
  • Headache
  • Fatigue
  • Nausea and vomiting

To read the full safety profiles of the vaccines, visit the MHRA websites for Pfizer/BioNTech, Oxford/AstraZeneca and Moderna.

If you experience any adverse reactions, you should report them on the Pfizer, AstraZeneca or Moderna websites.

Why have the Covid-19 vaccines been approved so fast?

Vaccine development is a rigorous process that usually takes at least 10 years to complete. The stages – pre-clinical analysis, clinical phases I-III, regulatory review and manufacture – ensure vaccines are safe, effective, and of high quality.

Covid-19 vaccines have undergone the same process in less than one year. This speed is due to several differences relating to the seriousness and scale of the pandemic:

  • The amount of money available has allowed the recruitment of more scientists and staff.
  • It has been easier to find the thousands of volunteers that are needed for testing.
  • Normally the stages take place one after the other, but with the Covid-19 vaccines, they have sometimes overlapped and the UK’s regulatory body has been given data to review as each stage took place.

You can learn more about each of the Covid-19 vaccine development stages with this BBC video.

If you are unsure of the safety of vaccines, learn how they are researched here and why they are important here.

Who should not be vaccinated?

The Covid-19 vaccines are safe for most of the population. However, there are a few considerations to take into account, (this is general information and you should consult your doctor to confirm or discuss any of the following):

  • As with other injectable vaccines, people with previous allergic reactions to a vaccine or a covid-19 vaccine, should not be vaccinated.
  • As with other intramuscular injections, the Covid-19 vaccine should not be given to individuals with a bleeding disorder (e.g. haemophilia, thrombocytopenia) or receiving anticoagulant therapy.
  • For people suffering from acute severe febrile illness, vaccine administration should be postponed. But it can be administered once it has passed.
  • Immunocompromised individuals, including those receiving immunosuppressant therapy may have a diminished immune response. There is not enough data available to determine the safety of the vaccine in these individuals.
  • There is limited data on the use of the Covid-19 vaccine in pregnant women so those who are pregnant should not routinely have this vaccine.

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