Coronavirus: What are the long-term health implications of Covid-19?

Six months into the Covid-19 pandemic, and with more than 380,000 people dead, the picture we have of Sars-CoV-2 remains opaque and unclear. Thousands of papers and reports have flooded the academic sphere during this period, as scientists have rushed to understand the virus, which, according to the journal Science, “acts like no pathogen humanity has ever seen”.

As governments have scrambled to stabilise the spread of Covid-19 within their countries, enforcing far-reaching mitigation measures that have overhauled the normalities of day-to-day life, our perception of this deadly disease has slowly shifted and changed.

What initially appeared to be a predictable respiratory infection, similar to Sars or Avian flu, Sars-CoV-2 is now known to affect the lungs, brain, eyes, nose, heart, blood vessels, livers, kidneys and intestines — virtually every organ in the human body.

The studies that have been conducted into Covid-19 present a vast array of symptoms and long-term effects among those who suffered severe infections: scarring of lung tissue; kidney failure; inflammation of the heart muscle and arrhythmias; liver damage; cognitive impairment; psychosis mood disorder, and much more.

What this means for the long-term health implications of patients has yet to be fully established, but the growing evidence suggests that even those who suffered from a mild case of Covid-19 may go on to struggle with issues long after the virus has left their bodies.

“What we have been seeing in hospitals is the tip of the iceberg,” Professor Roberto Pedretti, head of cardiology at the Clinical Scientific Institute in Pavia, Italy, told Good Health.

“Our focus at the moment is treating patients at the acute stage to help them recover from Covid-19. But we also need to consider the future health impacts of the virus.”

A March report from China showed that of 70 patients who survived Covid-19 pneumonia, 66 had developed some form of lung damage that was visible in CT scans.

The damage ranged from the formation of blood vessel blockages within the lung’s alveoli, which absorb oxygen, to scarring of lung tissue, researchers at Huazhong University of Science and Technology in Wuhan found. This scarring or thickening of lung tissue — known as pulmonary fibrosis — can lead to increased breathlessness among sufferers. There is currently no treatment that can stop or reverse this condition.

In a separate Wuhan study, researchers analysed the CT scans of 81 patients with Covid-19 and found signs of fibrosis even in those who had had no symptoms. Writing in the journal Lancet Infectious Diseases last April, scientists said it was unclear if these lung changes were “irreversible”.

Louise Wain, the GSK/British Lung Foundation chair in respiratory research and a professor at the University of Leicester, said that research was being done to ascertain how this type of fibrosis will develop in Covid-19 patients who developed severe symptoms and were forced onto ventilators.

“Fibrosis can resolve; it can remain stable and doesn’t change over time,” she told The Independent. “In some people it might have some effect but it could be quite negligible. They may not quite recover their full [lung] capacity but find it doesn’t have a massive detrimental affect.

“But there is also fibrosis that can progress. That’s the fibrosis that is really dangerous as that’s the one that is likely to kill people some time down the line. Those are the people we need to be looking out for. We can’t reserve fibrosis, but there are drugs that can slow it down.”

Separately, newly-released papers by the UK government’s Scientific Advisory Group on Emergencies (Sage) have highlighted concern among British academics that the virus may cause “extreme tiredness and shortness of breath for several months” in patients.

Minutes from a meeting on 7 May, attended by 50 people, including Sir Patrick Vallance and Professor Chris Whitty, state: “Sage also noted the existence of longer-term health sequelae (such as the persistence of extreme tiredness and shortness of breath for several months) and the importance of monitoring these impacts through longer-term cohort studies.”

Even before the UK had even gone into lockdown, the country’s Faculty of Intensive Care Medicine (FICM), a professional body responsible for training intensive care doctors, said some people who are struck down with severe cases of Covid-19 could be left with lung damage that takes as many as 15 years to heal.

The FICM highlighted that many admitted to intensive care have developed a condition called acute respiratory distress syndrome (ARDS) — a powerful inflammatory response across the lungs that causes fluids to leak from blood vessels into the alveoli, making breathing impossible without medical assistance.

A similar message of concern has been raised by the chairman of the Dutch Association of Physicians in Chest Medicine and Tuberculosis, who has warned that thousands of recovered Covid-19 patients in the Netherlands may be left with permanent damage to their lungs.

A paper published in JAMA Cardiology last March documented heart damage in nearly 20 per cent of 416 hospitalised patients in Wuhan. Another study from the city showed that 44 per cent of 36 patients admitted to intensive care had arrhythmias (irregular heart rhythm).

These issues are thought to be linked to the body’s ‘cytokine storm’ response, a hyper-inflammatory condition caused by an overactive immune system, seen among some coronavirus patients.

Studies suggest this can lead to the inflammation of the heart muscle (myocarditis), which may affect the organ’s electrical system — thereby producing abnormal heart beats — as well as its ability to effectively pump blood around the body, resulting in breathlessness.

Cardiovascular complications are not unique to Covid-19. Many viral infections can cause myocarditis. Although most people recover from the condition with time, some do experience permanent damage to the heart muscle.

Yuchi Han, an associate professor of medicine and radiology and director of cardiac MRI at the Perelman Centre for Advanced Medicine at the University of Pennsylvania, said that those with heart and vascular conditions were likely to suffer from greater damage as a result of their Covid-19 infection.

However, he warned that those without heart problems were not invulnerable. “The inflammation that occurs in the heart is not limited to people who have heart or vascular disease and could occur in anyone,” Dr Han told the Daily Mail. “However, we don’t yet know why in people who do not have risk factors some experience severe disease and others don’t.”

Disruption from Covid-19 also seems to extend to the blood itself. Among 184 Covid-19 patients in a Dutch ICU, 38 per cent had blood that clotted abnormally, and almost one-third already had clots, according to an April paper published in Thrombosis Research.

Although the lung appears to be the primary target zone for the virus, evidence suggests that Sars-CoV-2 is also targeting the kidneys in some patients.

According to research in Wuhan, 27 per cent of 85 hospitalised patients had kidney failure. A separate study found that 59 per cent of almost 200 hospitalised Covid-19 patients in China’s Hubei and Sichuan provinces had protein in their urine, and 44 per cent had blood; both indicators of kidney damage.

Those with acute kidney injury (AKI), were more than five times as likely to die as Covid-19 patients without it, the same paper reported.

“If these folks are not dying of lung failure, they’re dying of renal failure,” Jennifer Frontera, of New York University’s Langone Medical Center, told Science in April.

In a study of 214 Covid-19 patients, one-third experienced neurological symptoms, including dizziness, headache, and cognitive impairment.

At this stage, it is unclear what is driving these symptoms. Theories centre around the virus’ impact on the body’s neurons — the loss of smell and taste that some people have reported point to the pathogen’s affect on these nerve cells — the inflammatory immune response, and the oxygen deprivation that has been recorded in patients.

Cognitive impairments could be also associated with a stay in ICU, sometimes called ICU delirium. The condition, which can trigger hallucinations and paranoia, occurs more frequently among hospitalised elderly patients. Although most symptoms subside over time, some do not. Scientists have suggested that variables such as age, comorbidities and disease severity could influence Covid-19 patients’ cognitive recovery.

Professor Ed Bullmore, a neuroscientist at Cambridge University, told The Independent there was enough evidence now to describe the Sars-CoV-2 virus as causing a “neurotoxic illness”, adding that it was possible the psychiatric effects could last beyond a decade.

He said research had shown that a number of Covid-19 patients experienced a “kind of altered mental state”, adding that this included “cases of psychosis mood disorder and cognitive impairment”.

“We don’t know necessarily the causes of that neurotoxicity,” he said. “It could be that the virus infects the brain; it could be that the immune response to the virus damages the brain, or it could be the blood supply to the brain. All those mechanisms look plausible at the moment.”