Although vaccination and awareness have helped to quell the pandemic, millions of people are still dealing with lasting health consequences. Long Covid can last for weeks or months, with even a short walk leaving sufferers exhausted for days.

With medical services understandably focusing on critical and acute cases, while scientific research chased safety through vaccines, Long Covid was initially sidelined. But that's changing as time passes and data on the longer-term effects amasses. 

in December 2020, the U.S. made $1.5 billion of funding available for research and clinical trials into this puzzling new illness – and the knowledge base has grown thanks to efforts such as the UK's COVID-19 Symptom Study app, through which users who tested positive have consistently logged their health. 

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The app defines Long Covid as showing consistent symptoms for 28 days. Of the thousands of users, 13.3 percent had symptoms lasting for at least four weeks, 4.5 percent stayed ill for eight weeks and 2.3 percent suffered for longer than 12 weeks. 

By March 2021, according to a study by the Office of National Statistics, more than 1.1 million people in the UK reported having Long Covid symptoms. A May 2021 study suggested Long Covid caused the immune system to age prematurely, and an April 2022 Long Covid study published in The Lancet noted that women hospitalized by COVID-19 were more than 30 percent less likely than men to feel fully recovered 12 months after their infection.

The World Health Organization (WHO) says that around 10-20 percent of those who catch Covid-19 "may go on to develop symptoms that can be diagnosed as Long Covid," and says "it is believed that more than 17 million people across the WHO European Region may have experienced it during the first two years of the pandemic." 

The WHO also notes that "While common symptoms of Long Covid can include fatigue, shortness of breath and cognitive dysfunction over, over 200 different symptoms have been reported that can have an impact on everyday functioning."

Studying the data

Researchers at King's College London have consistently analyzed the figures, and a key study looked at predicting who might suffer from Long Covid. They found people with more than five symptoms in the first week were significantly more likely to go on to experience it.

The five first-week symptoms most predictive of Long Covid were fatigue, headache, shortness of breath, hoarse voice and myalgia or body aches. Asthma was the only pre-existing condition significantly associated with Long Covid. 

"If you have 10 symptoms ranging from headache to fatigue to abdominal pain – as well as those core symptoms we all know about fever, cough and loss of sense, taste or smell – then you're more likely to then go on to get Long Covid than if you just had a couple of symptoms," Clare Steves – one of the lead researchers at King's College London – tells RAZOR.

Long COVID-19, ME and CFS

One area of research is studying the similarities and possible connections between Long Covid, ME and Chronic Fatigue Syndrome (CFS). ME is myalgic encephalomyelitis – "myalgia" for the muscle aches and "encephalomyelitis" for the inflammation of the nervous system. ME and CFS have overlapping symptoms, and share similarities with post-viral syndromes.

Peter Rowe is a professor of pediatrics at the Johns Hopkins Children's Center, where he runs the Chronic Fatigue Clinic. As early as 2021 he began seeing adult Long Covid patients who share similar symptoms to those with ME/CFS. 

"For years it's been recognized that ME/CFS can be triggered by some sort of infection," he tells RAZOR. "There are cases from Hong Kong showing that people had illnesses that looked like ME/CFS after the original SARS pandemic."

Anthony Fauci, as chief medical adviser to U.S. President Joe Biden, repeatedly warned that Covid patients could develop ME/CFS, while the WHO's European arm quickly said understanding the long-term consequences of the coronavirus should be made a priority by health authorities. 

"If we can identify groups of people who are more likely to go on to Long Covid," says King's College London's Steves, "then we can give preventative treatments to those people. They then may go on to have a less long illness."

Long-term data, long-term effects

As the time passes, the data grows on the long-term effects – and the news is not encouraging. A March 2023 study published in JAMA Health Forum calculates that those who caught COVID-19 could have a doubled risk of death alongside higher risks of heart and pulmonary problems.

Analyzing insurance claims data for 13,435 adults with Long Covid and 26,870 who didn't have the virus, and factoring in pre-existing conditions, the study found that the Long Covid group had a higher mortality rate, with 2.8 percent dying compared to only 1.2 percent of the virus-free group.

While the global panic over the pandemic may be receding into memory, Long Covid is a serious medical issue for many – and it seems it will only add to the healthcare burden for many years to come. 

This story was originally published in March 2021 and substantially updated in March 2023. 

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