The answer

The Covid-19 vaccines approved for use in the UK by the independent Medicines and Healthcare products Regulatory Agency (MHRA) have all met strict standards of safety, quality and effectiveness. Any Covid-19 vaccine must go through the clinical trials and safety checks that all licensed medicines go through, and the MHRA follows international safety standards.

Like any medicine, the Covid-19 vaccines can cause side effects in some people; the majority are mild and should not last for longer than a week. The most common side effects include a sore arm, feeling tired, headache, feeling achy and feeling or being sick. Some people may develop a raised temperature or feel hot or shivery a day or two after having their vaccine. If they need to, they can take painkillers such as paracetamol.

There have been reports in the media about an extremely rare blood clotting problem affecting a very small number of people who have received the Oxford/AstraZeneca vaccine. The MHRA is carrying out a detailed review of these reports. This blood clotting problem can also happen in people who have not been vaccinated and it is unclear why it affects some people.

Covid-19 vaccines can help prevent people from becoming seriously ill or dying from Covid-19 and they have also been found to help protect against new variants. For people aged 40 and over, as well as those with other health conditions, the benefits of being vaccinated with the Oxford/AstraZeneca vaccine far outweigh any risk of potential clotting problems. If an individual received the first dose of this vaccine and experienced no blood clotting issues, they should go ahead and receive the second as planned.

For people under the age of 40 without other heath conditions, guidance from the MHRA and the Joint Committee on Vaccination and Immunisation states that it is preferable for them to have an alternative vaccine such as the Pfizer/BioNTech or Moderna vaccine instead of the Oxford/AstraZeneca vaccine where possible.