Can post-COVID increase the risk of thrombosis?
Research shows that the risk of thrombosis, such as a blood clot in the leg (deep vein thrombosis) or in the lungs (pulmonary embolism), can remain elevated for some time after a SARS-CoV-2 infection. This increased risk is primarily seen in the first three to six months after infection and applies not only to people who have been seriously ill, but can also occur in those with persistent symptoms consistent with post-COVID [1]. This doesn't mean that everyone with post-COVID will develop thrombosis, but it does mean that it's important to be alert to symptoms that could indicate this.
How can thrombosis develop post-COVID?
In post-COVID, various processes in the body can remain disrupted for a longer period. Scientific research describes that the lining of blood vessels, the so-called endothelium, can remain activated or damaged for a long time after a SARS-CoV-2 infection. As a result, the blood vessel partially loses its protective function against clotting [2,3]. Furthermore, there are indications that the blood in some people retains an increased tendency to clot for a long time, which can be reflected in elevated clotting values for months after the infection [3]. Persistent inflammation likely also plays a role, as inflammatory processes can continue to activate the clotting system. Finally, inactivity or prolonged lying down, which are common in post-COVID cases, can further increase the risk of thrombosis.
What can you do yourself to reduce the risk?
Although thrombosis cannot always be prevented, there are measures that can help reduce the risk. Regular exercise is important, even if it only occurs briefly. It is best to avoid sitting or lying still for long periods by, for example, moving around briefly every hour. Drinking enough fluids helps to make the blood less viscous. For people who are (partially) bedridden, regularly moving their feet and legs in bed can contribute to better blood circulation. In some situations, wearing support stockings can be helpful, but this should always be done in consultation with a doctor or healthcare provider. It is important not to use blood thinners without medical advice.
When should you contact your GP?
It's important to contact your GP the same day if you experience symptoms such as a suddenly swollen, painful, or warm calf or leg, or new, unexplained shortness of breath. For severe and sudden symptoms, such as severe shortness of breath, chest pain, fainting, coughing up blood, or sudden loss of function such as a crooked mouth or speech problems, call 112 immediately.
For healthcare professionals here more information about anticoagulation in post-COVID.
Sources
[1] Katsoularis I. et al. Risk of venous thromboembolism following COVID-19. BMJ, 2022.
[2] Crook H. et al. Long COVID: mechanisms, risk factors and management. Journal of Medical Virology, 2021.
[3] Jing Z. et al. Long COVID: pathophysiological mechanisms and therapeutic strategies. Signal Transduction and Targeted Therapy, 2022.
