Last April, a swedish study suggested that Covid-19 increased the risk of deep vein thrombosis (a blood clot in the leg) up to three months after infection, pulmonary embolism (a blood clot in the lungs) up to six months later and a bleeding event up to two months later. According to the researchers, the risk would also be higher in patients with comorbidities or those who have experienced a severe form of the disease.
A new study, conducted with 48 million unvaccinated Britons from the first wave of the pandemic confirms this risk. And she further clarifies that theCovid-19 infection increases risk of life-threatening blood clots for at least 49 weeks after infection. The authors of this study, published in the journal Circulationsuggest that the pandemic may have led to an additional 10,500 cases of heart attacks, strokes and other blood clot complications such as deep vein thrombosis in England and Wales alone.
Most previous studies have investigated the impact of covid on blood clotting in hospitalized people. The new study shows that there was also an effect on people whose covid infection had not led to hospitalization.
The importance of vaccination to prevent clots from forming
For the researchers, these results show first of all the importance of taking measures, in particular with regard to thegiving treatments that prevent clots from forming in the blood vessels to people who are most at risk, and finally reinforce the importance of vaccination against Covid-19.
It should be noted that the risks of thrombosis and pulmonary embolism were more marked during the first wave, in March 2020, compared to the second and third waves. An explanation which can be found in the subsequent improvements in treatments against Covid-19 and especially by the much higher vaccination coverage of the oldest patients.
Sources:
- Association of COVID-19 With Major Arterial and Venous Thrombotic Diseases: A Population-Wide Cohort Study of 48 Million Adults in England and Wales, Circulation, September 2022
- Risks of deep vein thrombosis, pulmonary embolism, and bleeding after Covid-19: nationwide self-controlled cases series and matched cohort study, The British Medical JournalApril 6, 2022