Researchers emphasize the importance of being vaccinated against coronavirus, stating that the risk of blood clot formation after vaccination is very low compared to virus-induced coagulation.
According to the research, the risk of blood clots is much higher in people who have contracted the Covid-19 disease caused by the coronavirus, and who have had to undergo hospital treatment, especially after severe illness, compared to those who have had the virus mildly or have not been caught at all.
The researchers aimed to determine when the risk returned to normal and whether the level of risk changed during various waves of the pandemic.
Within the scope of the research, the health status of 1 million people who tested positive for Covid-19 between February 2020 and May 2021 in Sweden were followed. The health status of these people was compared with 4 million people of the same sex and age groups who did not get the virus.
It has been determined that the following risks have increased after Covid:
- blood clots or deep vein thrombosis (DVT) in the leg for up to 3 months
- blood clots or pulmonary embolism in the lungs for up to 6 months
- Internal bleeding and stroke for up to 2 months
When the researchers compared the risks of blood clots after Covid with the normal risk level, they obtained the following results:
- While DVT developed in 4 out of every 10 thousand Covid patients, this rate was 1 in 10 thousand in non-Covid patients.
- While 17 out of every 10 thousand Covid patients had a blood clot in the lung, this rate was less than 1 in 10 thousand in non-Covid patients.
HIGHER RISK FOR THOSE SICK AT THE BEGINNING OF THE PANDEMIC
The findings of the study, published in the British Medical Journal (BMJ), show that the risk of clotting is higher in those who contract the virus in the first wave of the pandemic.
The researchers cited that in the next waves of the virus, new treatment methods were developed and vaccination rates increased.
Experts have determined that the probability of blood clot formation in the lungs of people with severe Covid-19 is 290 times higher than normal, and this rate is only 7 times higher in those who have had a mild virus. There was no increase in the probability of internal bleeding in those who had a mild infection.
“The probability of virus-induced coagulation is very high compared to vaccine-induced coagulation. This is a very important reason to vaccinate people who have not yet been vaccinated,” says Anne-Marie Fors Connolly, a researcher at Umea University in Sweden.
Researchers don’t yet know exactly why blood clots form after Covid-19, but they say it’s possible that the virus has settled on the cells lining blood vessels, so the body is overreacting to the virus.
Although vaccines are effective against severe Covid-19, they do not completely prevent catching the virus. That’s why people can get the virus several times.
Frederick K Ho, lecturer in the Department of Public Health at the University of Glasgow, says the study is a reminder that “we need to be mindful of possible complications” even in mild Covid infections.