Picture: Reuters
Picture: Reuters

Stellenbosch study finds what might cause lingering symptoms of long Covid

By Kelly Jane Turner Time of article published Oct 4, 2021

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Scientists from Stellenbosch University (SU) have found what might be the cause for some of the lingering symptoms experienced by patients with long Covid.

Researcher in the Department of Physiological Science at SU, Professor Resia Pretorius, said that blood samples from patients with long Covid contained an abnormal amount of micro clots.

The research group is the first to have reported on finding micro clots in the blood samples from individuals with long Covid using fluorescence microscopy and proteomics analysis.

“We found high levels of various inflammatory molecules trapped in micro clots present in the blood of individuals with long Covid. Some of the trapped molecules contain clotting proteins such as fibrinogen, as well as alpha(2)-antiplasmin,” she said.

Alpha(2)-antiplasmin is a molecule that prevents the breakdown of blood clots.

High levels of this molecule in the blood of Covid-19 patients significantly prevents the body’s ability to break down clots.

Under normal conditions the body maintains a fine balance between blood clotting — the process by which blood thickens to prevent blood loss after an injury — and fibrinolysis — the process which prevents blood clots from forming.

Pretorius said the lingering symptoms that occur in patients with long Covid might be due to the presence of persistent circulating plasma micro clots that are resistant to fibrinolysis.

The study has been peer-reviewed and published in the journal cardiovascular diabetology.

Researchers have found that lingering symptoms can persist for six months or longer after acute infection.

The most common long Covid symptoms include recurring fatigue or muscle weakness, being out of breath, sleep difficulties and anxiety or depression.

Senior analyst in the Mass Spectrometry Unit at SU’s Central Analytical Facilities, Dr Maré Vlok, said the blood plasma samples from individuals with acute Covid and long Covid continued to deposit insoluble pellets at the bottom of the tubes after dilution.

Vlok alerted Pretorius’ research group to this observation and they investigated it further.

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