Blood clots (thrombosis) and Covid-19

The coronavirus outbreak is changing the way we all live our lives, often this means thinking how to adapt and learning to live with uncertainty.

Despite the impact of the virus, the Thrombosis UK team are striving to provide continued support and information to all those affected by thrombosis and anyone who may be at risk, want to learn more or who is involved in blood clots -venous thromboembolism (VTE) prevention and care.

Working with our medical leads and following published advice from Public Health and NHS England, Thrombosis UK is committed to providing information on reducing VTE risks, supporting well-being and any known information on thrombosis and COVID-19.

COVID-19 vaccine and anticoagulation
December 9th 2020

The COVID-19 vaccine is given as an injection into your upper arm (intramuscular). Individuals receiving direct oral anticoagulant (apixaban, dabigatran, edoxaban & rivaroxaban) or warfarin in therapeutic INR range or on full dose heparin or fondaparinux injections can all receive the COVID-19 vaccination.

  • There is a risk of bruising at the injection site, but we do not anticipate any serious effects related to anticoagulation
  • We suggest that after the injection prolonged pressure (at least 5 minutes) should be applied to the injection site to reduce bruising
  • Patients on warfarin with supra-therapeutic INR should wait until their INR is <4.0
  • We encourage patients to have vaccinations and should not be avoided on the basis of being on anticoagulation


Please note, if you have any specific concerns or questions about your own health, please speak directly with your healthcare provider. Thrombosis UK is unable to offer individual medical advice and it would be unethical for us to provide you with that level of advice.

Thrombosis and COVID-19, current information:

  1. Having blood clots, such as deep vein thrombosis (DVT) or pulmonary embolism (PE), is not associated with an increased risk of acquiring COVID-19.
  2. Anticoagulants themselves don't place patients at risk for COVID-19. What can be important are underlying disorders. For example, if anticoagulants are given to someone with a blood clot associated with active cancer; then the cancer and its treatment may result in immunosuppression, which places patients at risk. It's important to talk to your doctor about your individual situation if you are concerned.
  3. D-dimer is a non-specific marker of inflammation or infection so it is not surprising that the levels will be high in those with the most severe Covid-19 infection. In some of the articles in the lay press, elevated D-dimer levels have been interpreted as indicating blood clots. This is an incorrect interpretation. Although D-dimer levels are elevated in most patients with blood clots, D-dimer levels also are elevated in many other disorders including infection. Therefore, an elevated D-dimer level in patients with COVID-19 infection alone is not evidence that they have a clot. For to up to date medical guidance and information for the public, in the UK visit: https://www.nhs.uk/conditions/coronavirus-covid-19/. There is also helpful information on the following sites: the World Health Organization (WHO), https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public which includes information on Myth Busters and basic protective measures.

Reducing your risk of blood clots while working from home or self-isolating

Being aware of risk factors, and especially of your own risk factors is really important in helping you to avoid and protect yourself from thrombosis.

Although some risk factors including hospitalisation and major surgery, carry more risk, if you are at home and less active, this can also be a risk factor for deep vein thrombosis, for instance:

  • Long-term bed rest
  • Long periods of inactivity including sitting for long period of time results in blood moving very slowly through the leg veins
  • Dehydration can also risk a risk factor as it causes blood to thicken

Look out for our interactive live Facebook activities to keep you moving and active despite being in self-isolation!

Further details shortly.

Maintaining your well-being while managing self-isolation

Clinical research has demonstrated that the psychosocial impact of venous thromboembolism (VTE) can belong-lasting and even life-changing. As many people will need to self-isolate or move their work to being home-based, it is very important to also support your psychological well-being as well as physical health

Thrombosis UK has a range of aids to help with managing worrying, sleeplessness and anxiety as a result of thrombosis.

Look out for our interactive sessions on relaxation and mindfulness, full details to follow.

Additionally, www.mind.org.uk has published useful information regarding wellbeing and coronavirus, including for those who are self-isolating.


Blood clots, thrombophilia and COVID-19
Prof Beverley Hunt OBE
November 2020



ISTH - COVID-19 and Thrombosis: ‘Ask The Expert’ with Prof Beverley Hunt OBE


Thrombosis & Covid-19, an update

Professor Beverley Hunt OBE, message from Thrombosis UK


Webinar: Patient Information & Support webinar: Thrombosis Q & As’ with Professor Beverley Hunt OBE


Thrombosis UK is delighted to welcome you to its' very first online dedicated Patient Information and Support meeting.

Led by Prof Beverley Hunt OBE, the meeting will offer opportunity to pre-submit questions, learn more about blood clots and hear updates on the management of blood clots, Covid-19 and insight on restoring health and well being following diagnosis of thrombosis.

Watch Video

Anticoagulation during Covid-19

Download Document

Anticoagulation during Covid-19

Dr Matthew Fay GP with Affinity Care PCN Bradford - Trustee Thrombosis UK and Clinical Advisor to Anticoagulation UK


Blood Clots and Covid-19

Professor Beverley Hunt OBE, Consultant Haematologist, and co-Founder & Medical Lead Thrombosis UK.


World Thrombosis Day: Ask the Expert with Jeffrey Weitz, M.D.: COVID 19 and Thrombosis



Prof Beverley Hunt OBE was interviewed by BBC Radio 4 on the Today Programme to discuss the occurrence of thrombosis in severely ill, hospitalised COVID-19 patients. https://www.bbc.co.uk/sounds/p... (45-49 mins into the programme).

If you have experienced a blood clot as a result of Covid-19 we would welcome hearing from you to help raise greater awareness and understanding on this previously unseen challenge. To contact please email jo@thrombosisuk.orgr

We would also welcome hearing from individuals who have a history of thrombosis and in the recent Covid-19 pandemic, developed Covid-19 and have made a full recovery. If you were willing to share your experience it would be extremely reassuring for others with a medical history of thrombosis. Thank you.


Anne was diagnosed with Antiphospholipid Syndrome (APS) in 2015, has a history of blood clots, and then in March 2020, developed COVID-19

I am a 54-year-old female, working as a nurse in the NHS and diagnosed with Antiphospholipid Syndrome in 2015 following an admission to hospital in May 2014 with unprovoked bilateral pulmonary emboli. This is an account of my experience of COVID-19 in March this year. The first sign I had that something was wrong was on 2nd March when I was at work and a colleague mentioned I looked flushed. When I got home, I took my temperature and was shocked to see it was 39.1 Celsius. I contacted 111 and was advised my GP would have to see me that evening. The GP asked some questions prior to me attending, mainly regarding travel to China or Italy. He checked my throat, ears, urine and nothing out of the ordinary was evident. He suggested I could be brewing something and to see how I felt over the next few days. Well I continued to feel fine so carried on as normal.

All was good until 14th March when I though I was developing a sore throat, no high temperature until the following evening (when I was preparing for work the following day) I took my temperature which was 38.7 Celsius. I was not feeling particularly unwell but by this stage there was a clear instruction not to go to work with a high temperature.

This was just the beginning, the next 10 days were spent bedridden with an unrelenting fever, no energy to do anything, unable to eat or drink due to diarrhoea plus having no appetite (even the thought of swallowing paracetamol made me feel nauseous). The only thing I could keep down was small sips of water. I remember it took me 1.5 hours to work up the energy to get out of bed to go to the bathroom. As a measure of how little energy I had, I was unable to shower or bathe for the 10 days. I did develop the dry cough but not until day 6.

I did contact 111 and was called back after 36 hours, to be told I wasn’t ill enough for hospital but if I reached a point of being unable to breathe to phone 999. It was a frightening time, feeling the most unwell I’d ever felt in my life but no option to attend the GP, who stayed in contact with me by email. I got out of bed one morning and everything went black, this was probably the lowest and worst point of the virus.

However, after 2 weeks I felt I was starting to recover and another week at home made me feel well enough to return to work. I should mention I continued to take my warfarin throughout the 3 weeks and when I was able to return to the Anticoagulation Clinic had an unmeasurable INR and required Vitamin K to urgently reverse the warfarin. In retrospect I was lucky to be taking warfarin as the accounts of sticky blood with COVID-19 are of great concern if you are already diagnosed with Antiphospholipid Syndrome.

Repercussions of the illness have been fatigue meaning I sometimes got into bed as soon as I got home from work and afternoon naps becoming a regular feature of my weekends. The other alarming side-effect was hair loss, which started about 3 months post COVID-19. I am happy to say both are now lessening.

Medical comment
COVID-19 can present in three forms- mild- when the patient is unwell but does not have shortness of breathe; moderate- when patients gets SOB and low on oxygen in the blood due to pneumonia caused by the virus; and lastly severe –when the patient requires support from mechanical ventilation to breathe.
This is a description of “mild” COVID-19 although it was far from mild as far as symptoms are concerned.

It is really important to note that the risk of having COVID-19 and the risk of getting COVID-19 pneumonia are not increased in those with previous blood clots. Blood does get very sticky in those who have COVID-19 pneumonia, but not in those with mild COVID-19.

There is no evidence that those with recognised conditions such as antiphospholipid syndrome will get more blood clots than someone who does not have antiphospholipid syndrome, but obviously it is important to keep taking anticoagulation.

Taking warfarin, one needs to make sure that the intake of vitamin K is the same every day (it is mainly in green food in the British diet) so not eating when ill, as in this description will lead to a very high INR.

This very good description of having mild COVID-19 occurred in March when there was little testing. Now one would automatically go for COVID-19 PCR testing with the first symptoms.


Becky’s account of blood clots in a time of COVID-19

[Horse Hounds July 2020]

A rider who spent three weeks in hospital with severe blood clots has warned others to be aware of the life-threatening condition.

Becky Read suffered deep vein thrombosis and pulmonary embolism some six weeks ago and was lucky she did not lose her leg — or her life.

Becky told H&H she first noticed issues a fortnight before she was admitted to hospital; she had been training for a half-marathon but found herself very short of breath on short runs. She was also experiencing muscle pains.

“A couple of days later, I woke up in the night, in the worst pain I’d ever experienced,” she said. “It was as if someone was stabbing me, on the whole right side of my torso; I was screaming in pain.”

Becky called 111 and was told Covid-19 can cause muscle pains so she had a test, which was negative. She and her partner were told to self-isolate in case the test was inaccurate, but she experienced more severe muscle pains, nausea, confusion and light-headedness over the next few days.

Read Full Story [Horse & Hounds]