Covid-19 infection raises risk of life-threatening blood clots, warns new study

Even as Covid-19 cases are dropping in numbers, the risk of post infection health condition continues to lurk right around the corner with a new study revealing that the infection with SARS-CoV-2 virus reportedly increases the risk of potentially life-threatening blood clots for at least 49 weeks. 

The study conducted in the UK, published recently in the journal Circulation, found that in the first week following a Covid-19 diagnosis, people were 21 times more likely to have a heart attack or a stroke, conditions mainly caused by blood clots in arteries. 

Notably, after 4 weeks, the likelihood dropped to 3.9 times, according to the study. The team, led by researchers from the Universities of Bristol, Cambridge, Edinburgh, and Swansea University, UK, also studied conditions caused by blood clots in veins, such as deep vein thrombosis and pulmonary embolism, the latter being potentially fatal, according to PTI report.

Additionally, they found that in the first week of diagnosis, people were 33 times more likely to develop blood clots in the veins, and after 4 weeks, 8 times more likely. While a higher risk of blood clots after Covid-19 remained for the entire study duration, from week 26 to week 49, the likelihood of blood clots developing had dropped to 1.3 times in arteries and 1.8 times in veins, the report said.

“We are reassured that the risk drops quite quickly – particularly for heart attacks and strokes – but the finding that it remains elevated for some time highlights the longer-term effects of Covid-19 that we are only beginning to understand,” said Jonathan Sterne, who co-led the study.

The researchers also found that people with mild or moderate disease who were not hospitalised too were affected, though the excess risk was not as high as those with severe disease and requiring hospitalisation.

“We have shown that even people who were not hospitalised faced a higher risk of blood clots in the first wave, even though the risk to individuals remains small," said Angela Wood, another co-lead of the study.

Additionally, the researchers studied de-identified electronic health records across the whole population of England and Wales from January to December 2020 to compare the risk of blood clots after Covid-19 with the risk at other times. “The effect that coronavirus infection has on the risk of conditions linked to blood clots is poorly studied, and evidence-based ways to prevent these conditions after infection will be key to reducing the pandemic's effects on patients,” said William Whiteley, who co-led the study. 

(With inputs from PTI)