Why impact of ‘long COVID’ could outlast the pandemic

Millions of people who have gotten COVID-19 and survived are finding that a full recovery can be frustratingly elusive. Weeks or even months after seemingly recovering from even a mild case, many patients still confront a wide range of health problems.

As researchers try to measure the duration and depth of what’s being called “long COVID,” specialised, post–acute COVID-19 clinics are opening to handle the patients. The scale of the pandemic and persistence of some of COVID-19's disabling effects mean the economic pain and drain on health resources could continue well after the contagion ends.

WHAT DO WE KNOW ABOUT LONG COVID?

Most patients who suffer from COVID-19 fully recover, but some suffer long-term pulmonary, cardiovascular and nervous-system problems as well as psychological effects. These can occur irrespective of the initial severity of the SARS-CoV-2 infection, but happen more frequently in women, the middle-aged, and in individuals who experienced more COVID-19 symptoms initially.

Although most long COVID symptoms don’t seem to be life-threatening, a study published in April 2021 in the journal Nature found that sufferers had a 59 per cent increased risk of dying within six months. That works out to about eight extra deaths per 1,000 COVID-19 patients - adding to the pandemic’s hidden toll.

WHAT'S THE DEFINITION?

According to the World Health Organization, people with what it calls “post Covid-19 condition” have symptoms usually three months after an initial bout of COVID-19 that last for at least two months and can’t be explained by an alternative diagnosis.

Common ones include fatigue, shortness of breath and cognitive dysfunction - all of which affect everyday functioning. These ailments may appear following recovery from the acute phase of COVID-19 - even one with no noticeable symptoms - or persist well after the initial illness. Symptoms may also fluctuate or relapse over time.

The WHO says this definition may change as new evidence emerges, and that a separate definition may be needed for children. Other groups have proposed alternative definitions based on the constellation of symptoms affecting such people, who are colloquially known as long-haulers.

HOW PREVALENT ARE LONG-TERM EFFECTS?

Researchers haven’t studied enough cases over a long enough period to gauge the full range of effects, what proportion of patients will suffer from them or for how long. Various published studies indicate that about 10 to 20 per cent of people experience lingering symptoms for weeks to months after infection.

Early findings and the demand for specialised clinics to help survivors deal with scarred lungs, chronic heart damage, fatigue and other conditions indicate a significant prevalence. About 1.1 million people in the UK reported experiencing long COVID as of early September, according to the Office for National Statistics. Of those:

• 405,000, or 37 per cent, had confirmed or suspected COVID-19 at least one year previously;
• 706,000, or 65 per cent, said symptoms adversely affected day-to-day activities;
• 211,000, or 19 per cent, reported that their ability to undertake day-to-day activities had been "limited a lot".

IS COVID-19 DEFINITELY TO BLAME FOR THESE SYMPTOMS?

Not necessarily. A large study based on data from a US health plan published in the BMJ in May found that 14 per cent of people infected with the coronavirus developed one or more related complications requiring medical care beyond the acute phase. But so did 9 per cent of people in a control group. Some symptoms might occur by chance or be triggered by stress and anxiety.

Social restrictions, lockdowns, school and business closures, loss of livelihood, decreases in economic activity and shifting priorities of governments all have the potential to substantially affect mental health, according to a study that appeared on Oct 8 in the Lancet.

It found the pandemic has resulted in an extra 53.2 million cases of major depressive disorder and an extra 76.2 million cases of anxiety disorders globally. In some critical COVID-19 cases, life-saving treatment itself may cause problems. Such uncertainties have sometimes led to what patients describe as “medical gaslighting” by health professionals who don’t take their complaints seriously, especially if the patient is a woman.

WHAT ARE THE BROADER IMPLICATIONS?

Some researchers say the pandemic may spur a raft of long-term problems such as chronic fatigue syndrome, dementia, Parkinson’s disease, diabetes and kidney impairment. An uptick in treatments for depression, anxiety and pain has stoked concern of a spike in suicides and opioid overdoses.

The US Centers for Disease Control and Prevention reported a surge in overdose deaths in 2020. The reduced work hours reported in 69 per cent of patients indicate the pandemic is having an impact on labor productivity. With almost 240 million confirmed infections worldwide as of October, even a small share with long-term disability could have enormous social and economic consequences. And these will be magnified if problems end up lasting for years or decades.

DO OTHER VIRUSES CAUSE PROLONGED ILLNESS?

Yes. So-called post-viral syndromes occur after infections including the common cold, influenza, HIV, infectious mononucleosis, measles and hepatitis B. Diabetes and other long-term consequences were observed in survivors of severe acute respiratory syndrome (SARS), which is caused by coronavirus related to SARS-CoV-2.

A Canadian study identified 21 health-care workers from Toronto who had post-viral symptoms for as long as three years after catching SARS in 2003 and were unable to return to their usual work. Some people who were hospitalised with SARS in Hong Kong still had impaired lung function two years later, a study of 55 patients published in 2010 found. Still, it’s not known yet whether the lessons of SARS are applicable to COVID-19.

WHAT IS BEING DONE?

In the US, Congress is providing some US$1.15 billion in funding over four years for the National Institutes of Health to support research into the long-term effects of COVID-19. The studies hopes to get at issues such as the underlying biological causes and how they might be treated and prevented. Some researchers are pressing governments to focus attention not only on infection and vaccination rates but on potential long-term organ damage.

For example, researchers have shown the virus can infect insulin-producing pancreatic tissue, potentially triggering diabetes that in some cases persists beyond the acute infection. That’s prompted Australia’s Monash University and King’s College London to create a global registry for studying “new onset” diabetes. Some long haulers have reported feeling better after receiving a Covid vaccination, prompting researchers to examine the phenomenon and whether vaccines can offer clues to treatment.

Avindra Nath, clinical director of the US National Institute of Neurological Disorders and Stroke, said vaccines, including for flu, have been known to help patients with chronic fatigue, but relief has almost always been temporary.