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Covid-19 Primary Care Resources

Adverse effects of Covid vaccines

The most frequently reported adverse effects to the different vaccines and when to report an adverse effect

This information is sourced from the MHRA Guidance on Astrazeneca, Pfizer/BioNTech and Moderna Covid-19 Vaccines and the Specialist Pharmacy Service :

  • Any vaccine may produce unwanted or unexpected adverse reactions
  • Currently, the adverse effects from all three approved Covid-19 vaccines are mild, transient and much less serious than developing Covid-19 or the complications associated with Covid-19
  • These majority of adverse effects reflect the normal immune response triggered by the body to the vaccines. They are typically seen with most types of vaccine and tend to resolve within a day or two
  • There have been reports of an extremely rare adverse event of concurrent thrombosis and thrombocytopenia following vaccination with the first dose of AstraZeneca vaccine.  Patients should seek immediate medical attention if four or more days after vaccination if they develop new onset or worsening severe or persistent headaches with blurred vision, which do not respond to simple painkillers or if they develop new symptoms such as shortness of breath, chest pain, leg swelling, persistent abdominal pain, any neurological symptoms or signs (such as confusion or seizures) or unusual skin bruising and/or petechiae.

Reporting of suspected vaccine adverse reaction

Report any suspected side effects, even minor ones, to any Covid-19 vaccines on a Yellow Card

When reporting, patients and healthcare professionals are encouraged to provide as much information as possible. Where available the following information should be provided:

  • Information on the person who has experienced the side effect
  • Whether the side effect is related to the first or second dose of the vaccine
  • The date of the vaccination
  • The name and batch number of the vaccine suspected to have caused the side effects
  • A description of the side effects
  • Any other medicines being taken around the same time (including non-prescription and herbal remedies)
  • Any other health condition that the person who experienced the side effect may have

Alternatively, adverse events of concern can be reported directly to the pharmaceutical company. Please do not report the same adverse effect to both systems as dual reporting will create unnecessary duplicates

AstraZeneca: Telephone 0800 0541028

Pfizer: Telephone 01304 616161

Moderna: Telephone 0800 0857562 or

As of 31 January 2021, for the UK:

  • 20,319 Yellow Cards have been reported for the Pfizer/BioNTech vaccine
  • 11,748 have been reported for the Oxford University/AstraZeneca vaccine
  • 72 have been reported where the brand of the vaccine was not specified

For all vaccines the overall reporting rate is around 3 to 4 Yellow Cards per 1,000 doses administered.

Written by Dr Abdul Zubairu