Doctor’s definition of Covid-19 sparks debate in SA medical circles

As Covid-19 continues to cause global devastation, it has also become one of the most discussed diseases of the century, with its definition igniting a debate in South African medical circles.

Amid what seemed to be a schism on how infectious disease experts have defined Covid-19, following Western Cape vascular biologist Dr Jaco Laubscher maintaining it was a vascular disease and not respiratory – Tygerberg infectious disease specialist and academic Dr Jantjie Taljaard has drawn a link, saying the coronavirus was “a viral respiratory tract infection” which could affect “the small vasculature around the lungs”.

In a recently posted YouTube video, which attracted over 130,000 views, Laubscher said that Covid-19 was a vascular and not a respiratory disease, which affected vulnerable endothelium, leading to hyper-coagulability and impaired fibrinolysis.

Said Taljaard: “Covid-19 is a viral respiratory tract infection that can present completely asymptomatic in up to 30% of people, with mild, flu-like symptoms in about 60% of patients – with a pneumonia in around 10% to 15%.

“A week after infection occurs, some people develop an abnormal immune response that precipitates a condition called acute respiratory distress syndrome, which has a profound effect on oxygen transfer in the lungs.

“This also affects the small vasculature around the lung, causing inflammation, clotting and may also precipitate multiorgan failure. This can be complicated in a very small percentage of patients with increased clotting in larger vessels.”

Also read: Global experts warn of Covid-19 airborne threat

Taljaard said he did not share a perception that the medical profession was divided on the virus definition.

“There may be an alternative hypothesis, but as a profession across the world, everyone still endorses the available evidence that Sars-CoV-2 is a respiratory tract pathogen. New hypotheses must be tested to determine validity and safety before the scientific community can endorse it universally with confidence.

“A pandemic gives us the opportunity to test these hypotheses in a short time span and potentially learn more about disease processes in one year than we would have learnt over a decade,” said Taljaard.

Professor Graeme Meintjies, University of Cape Town and Groote Schuur Hospital deputy head of medicine, said arguments on whether the disease was respiratory or vascular in nature were “not particularly helpful”.

“The reality is that both organ systems can be involved and, in addition, other organs such as the kidneys can also be severely affected,” he said.

“Our diagnostic and treatment approaches need to be all-encompassing. Most patients with severe Covid-19 who are hospitalised have a viral pneumonia with inflammatory damage to the tiny sacs [alveoli] in the lungs responsible for delivering oxygen to the bloodstream. A substantial minority of patients also have clinical features suggestive of a blood vessel disease – such as clots in their leg veins that may embolise to their lungs, strokes or heart attacks.”

Meintjies said in post-mortem studies of patients who have died of Covid-19, researchers have seen evidence of both severe damage to the lung’s alveoli and clots in the small blood vessels of the lung “suggesting that injury to both contributes to severe disease”.

University of Stellenbosch senior medical lecturer Dr Jo Barnes, said the vascular effect was “just one of the complications of Covid-19”.

Barnes, an epidemiologist, said: “Covid-19 is not at all a vascular disease. One of the common side effects of Covid-19 has been that it does have an effect on the vascular system – but that does not happen to everybody. You can get heart problems, blood clots and serious neurological fallout symptoms, but that does not happen to everybody.

“It is not primarily a cardiovascular disease. The virus can attack the body, the cardiovascular system, the neurological system, but the primary organ it attacks are the lungs.”

– brians@citizen.co.za

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