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Covid-19 Primary Care Resources

Coagulation disorders and anticoagulation treatment

Vaccination guidance for individuals with clotting and bleeding disorders and those on anticoagulation therapy

This information is sourced from the MHRA, The British Society for Haematology (BSH) and The Green Book, chapter 14a, by Public Health England 

Coagulation disorders

MHRA Guidance on administration of the Covid-19 AstraZeneca vaccine from 7th April 2021:

Administration of the Covid-19 AstraZeneca vaccine in patients with a history of the following conditions should be only be considered when the potential benefit outweighs any potential risks:

  • cerebral venous sinus thrombosis
  • acquired or hereditary thrombophilia
  • heparin-induced thrombocytopenia
  • antiphospholipid syndrome

Patients who have experienced major venous and arterial thrombosis occurring with thrombocytopenia following vaccination with any Covid-19 vaccine should not receive a second dose of Covid-19 AstraZeneca vaccine. Patients should seek immediate medical attention if four or more days after vaccination 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.

BSH guidance of 9th April is that ‘there is no evidence that individuals with a prior history of thrombosis or known risk factors for thrombosis are more at risk of developing this immune complication of AZ vaccine. Furthermore, for the majority of individuals, the risk of recurrent thrombosis due to Covid-19 infection is greater than the risk of this syndrome’


  • Individuals who are stable on anticoagulant therapy can be vaccinated 
  • Patients on warfarin should be up to date with their INR monitoring with an INR below the upper level of their therapeutic range 

Vaccination Method 

  • Use a fine needle (23G or 25G). 
  • Press firmly for 2 minutes following vaccination 
  • Advise patients of the risk of haematoma 

Written by Dr Claire Davies