A Stellenbosch University professor and her team may have cracked the mystery of what causes long Covid, which has hit up to 100-million people globally.
A study by professor Resia Pretorius, the head of physiological sciences, found that an overload of inflammatory molecules trapped inside microscopic blood clots could cause of some of long Covid’s symptoms.
Results of the research — using plasma samples from healthy individuals, those with type 2 diabetes, acute Covid and long Covid — have been published the journal Bioscience Reports.
According to the World Health Organisation (WHO), women and health-care workers appear to face the highest risk of long Covid, and the organisation has urged scientists to make understanding the condition a priority.
Pretorius told the Sunday Times that “acute Covid-19 is not only a lung disease, but actually significantly affects the blood flow and blood clotting systems”.
“A recent study in my lab revealed that there is significant microclot formation in the blood of both acute Covid-19 and long Covid patients,” she said.
“With healthy physiology, clots may form — for instance, when you cut yourself. However, the body breaks down the clots efficiently by a process called fibrinolysis.
“In blood from patients with long Covid, persistent microclots are resistant to the body’s own fibrinolytic processes. We found high levels of various inflammatory molecules trapped in the persistent microclots.”
22%: Decline in active lab-confirmed Covid cases in the past week
338: Excess deaths per 100,000 people in 2021
— In Numbers:
Pretorius said the presence of microclots and hyperactivated platelets — also involved in clotting — results in cells not getting enough oxygen to sustain bodily functions, a condition called cellular hypoxia.
“Widespread hypoxia may be central to the numerous reported debilitating symptoms,” said Pretorius.
Patients with long Covid complain of symptoms including recurring fatigue and brain fog, muscle weakness, being out of breath, sleep difficulties and anxiety or depression.
Some people are so sick they cannot work or walk a few steps. There may also be elevated risk of stroke and heart attacks.
Pretorius said the main focus of South African health professionals had been caring for acute Covid patients in hospitals. “Very little attention is given to the severely ill and sometimes disabled people that just never recover from persistent symptoms.”
Urgent investment was needed in research and clinical trials “to better understand and further confirm the link between abnormal blood clotting, hypoxia and vascular dysfunction in patients with long Covid”.
Noluthando Nematswerani, head of Discovery Health’s centre for clinical excellence, said long Covid is not yet fully understood.
“Long Covid affects every aspect of life, it affects one’s mental health and one’s ability to focus and work, and could have economic consequences too. This is why it’s so important that we acknowledge the prevalence and growing awareness around long Covid.”
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