Overall, the MHRA found nothing unusual about the safety data it has collected to date. Most reports were about mild and temporary injection site symptoms, like pain and itching, or about symptoms like headache, chills, fatigue, and nausea—just as the clinical trial data had shown. There were a few reports of severe allergic reactions, largely to the Pfizer/BioNTech vaccine, but they appear to be very rare. The UK and other countries now advise that people with a history of severe allergy to any vaccine ingredient should avoid it for the time being, and it’s now standard practice for patients to wait 15 minutes nearby in case there’s any need for immediate treatment of anaphylaxis.

The MHRA also found no evidence of an increased risk of Bell’s palsy, a temporary facial paralysis, following vaccination (some clinical trial data has suggested this as a possible risk). And while some people have died after vaccination, the MHRA has found no evidence to date that vaccines played any role in these deaths.

“Based on current experience, the expected benefits of both covid-19 vaccines in preventing covid-19 and its serious complications far outweigh any known side effects,” the MHRA concluded.