The COVID-19 increases the risk of developing serious blood clots up to six months after infection, according to a study published in the British Medical Journal (BMJ).
The Swedish study reveals an increased risk of deep vein thrombosis up to three months after COVID-19 infection, of pulmonary embolism up to six months later, and of a bleeding event up to two months later.
The risk is higher among patients with comorbidities and those with severe COVID-19and was more marked during the first pandemic wave than in the second and third, according to the study.
COVID-19 was known to increase the risk of serious blood clots, known as venous thrombosis, but there was less information on the period during which the risk was greatest and whether it varied during different pandemic waves.
To carry out the study, Researchers identified more than one million people in Sweden infected with the coronavirus between February 1, 2020, and May 25, 2021, and matched them by age, gender, and place of residence with four million people who were not. infected.
With this, they calculated the rates of deep vein thrombosis, pulmonary embolism and bleeding among people who had COVID-19 throughout the control period and compared it with the group without contagion.
According to the researchers, the higher risks observed during the first wave compared to the next two could be explained by improvements in treatments and vaccine coverage among older patients.
For researchers, the results justify taking steps to prevent thrombosis (such as giving treatments to prevent blood clots), particularly for high-risk patients.
They also highlighted the importance of vaccination against COVID-19.