Dr Muiris Houston: Mounting evidence of link between Covid and a … – The Irish Times

Covid-19 hasnt gone away. But, almost four years after it was first identified, the infectious disease certainly features less in the zeitgeist. People can be forgiven for placing Covid on the back burner of their psyche.

Most of the population does not qualify for further booster immunisation against the virus, which also diminishes its day-to-day relevance. However, the evidence for long-term health effects as a result of Covid continues to mount.

Probably the most significant finding to emerge recently is a definite link between Covid infection and a range of heart diseases. Even those who had a relatively mild dose and who made a good recovery are developing heart symptoms in the first year after they were initially infected.

For up to a year after a case of Covid-19, people are at increased risk of developing a new heart-related problem irregular heartbeats, spikes in blood pressure, blood clots and heart attacks. All occur more often, research shows.

Heart attack-caused deaths rose during every Sars-CoV-2 viral surge. This was especially marked among young people, with US research identifying an almost 30 per cent increase in heart-attack deaths among 25- to 44-year-olds in the pandemics first two years.

A large 2022 study of some 691,455 patients published in The Lancet found that in the year after a Covid infection, people were 1.5 times more likely to have a stroke, nearly twice as likely to have a heart attack, and had between 1.6 and 2.4 times the risk of developing different types of heart rhythm problems.

Researchers... found that those who had been diagnosed with mild Covid, had stiffer and more dysfunctional arteries than a control group who hadnt contracted Covid

Thats a substantial risk and begs the question: how is Covid infection damaging our hearts and our blood vessels?

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Inflammation is one possibility. We have had post-infection links to heart damage before in the form of rheumatic fever. This is an inflammatory reaction to untreated (prior to antibiotic availability) streptococcal throat infection that caused scarring of the hearts valves.

Researchers from the University of Portsmouth and the University of Split found that those who had been diagnosed with mild Covid, had stiffer and more dysfunctional arteries than a control group who hadnt contracted Covid. These changes are often the precursor to the development of cardiovascular disease. The study, while small, suggests we will have an increase in cardiovascular disease in the future as a result of Covid-19 infections.

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Then, in September came the first evidence that Sars-CoV-2 affects blood vessels directly. A research team, led by Dr Chiara Giannarelli at New York University School of Medicine, analysed coronary artery tissue samples from eight older people who died of Covid-19. The team found Sars-CoV-2 genetic material in coronary artery tissue from all patients. They found more viral RNA in the arterial walls than in the surrounding fat tissue. Many of the infected cells were macrophages, a type of white blood cell that helps remove cholesterol from blood vessels.

Another important question is whether Covid vaccine helps protect our hearts by reducing the inflammatory effects of the virus

The findings suggest that Sars-CoV-2 may increase the risk of heart attacks and stroke by infecting artery wall tissue. This provokes inflammation in atherosclerotic plaques, a known precursor to developing a heart attack or stroke. It appears that the immune cells most involved in atherosclerosis may serve as a reservoir for the virus, giving it the opportunity to persist in the body over time, said Giannarelli.

This breakthrough offers a likely explanation for the original finding that people who had Covid-19 have an increased risk of cardiovascular disease or stroke up to one year after infection. Obviously the study was limited to the analysis of a small group of older individuals with COVID-19 and pre-existing blocked arteries. So follow-up research will need to look at larger numbers, including younger and previously healthy individuals.

Another important question is whether Covid vaccine helps protect our hearts by reducing the inflammatory effects of the virus.

Until we find out, my strong advice to those of you eligible to get the booster is go for it.

muiris.houston@irishtimes.com

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