Most people who become infected with COVID-19 recover within a month. There is a significant patient population, however, who experience new, returning or ongoing health problems more than four weeks after their initial infection – even when their original infection was mild or asymptomatic. The U.S. Office for National Statistics estimates that 1 in 10 patients exhibit symptoms of COVID-19 infection for 12 weeks or longer, equating to more than 5 million cases worldwide. Now, more than a year after the pandemic’s beginnings, data from multiple studies are showing that the health issues presented by “long COVID” are perhaps even more widespread and serious than originally thought.
The long-term health problems resulting from COVID-19 infection can be highly variable and affect any organ system, with symptoms manifesting in widely varying combinations. COVID-19’s long-term effects extend from fatigue and cognitive deficits to a broad spectrum of issues involving the heart, lungs, kidney, skin, muscles and immune system. Moreover, the severity of such effects can range from mild to incapacitating. A 2020 Italian study found that 87.4% of hospitalized COVID-19 patients reported at least one symptom of the infection more than two months after they were discharged. Those patients who experienced more than five symptoms during their first week of infection were more likely to develop long COVID.
Abnormal fatigue and continued breathing problems are the most commonly reported symptoms, along with neurological and cognitive issues. In May, the Mayo Clinic issued a report based on the first 100 patients to receive care through the institution’s rehabilitation program for those with long COVID symptoms, only 25% of whom had been hospitalized for their initial infection. Most of the patients in the study had no underlying health problems before their infection and were relatively young – an average age of 45. Approximately one-third of the patients were sufficiently debilitated that they had problems performing basic activities, such as showering, dressing themselves, or eating. About 30% were unable to get back to working in any form.
A study by researchers at Washington University School of Medicine, published in late April in Nature, looked at data from 87,000 patients diagnosed with COVID infection, including those who did not become sick enough to require hospitalization, and five million non-infected control subjects. The researchers found that COVID survivors had a 60% increased risk of death six months following their diagnosis compared to non-infected subjects; the excess deaths among all COVID survivors were estimated at 8 per 1000 patients. Hospitalized patients who survived at least 30 days after their discharge experienced an even higher incidence compared to the control group – 29 excess deaths per 1,000 patients over the following six months.
A separate analysis by the Washington University team, employing Veterans Hospital Administration data from 13,654 hospitalized patients with COVID and 13,997 hospitalized with seasonal flu, found that, post-hospitalization, many of the COVID-19 patients were newly diagnosed with major health issues that persisted for at least six months, including respiratory, neurologic, mental health and cognitive, metabolic (including new diabetes onset), cardiovascular, gastrointestinal, kidney, and/or skin symptoms, as well as general malaise, fatigue and anemia. The researchers also found increased use of pain medications, antidepressants, anxiolytics, anti-hypertensives, and oral hypoglycemic medications, as well as evidence of lab abnormalities affecting multiple organ systems in COVID survivors. Moreover, the research team reported that COVID survivors experienced a 50% higher risk of death and a substantially higher risk of long-term medical problems compared to those who had been hospitalized with seasonal flu. The researchers are continuing to follow the patients in this study, as they believe that further long-term health consequences of COVID-19 may emerge over time.
Finally, data released in April by the Centers for Disease Control similarly reported that approximately two-thirds of those experiencing a mild COVID-19 infection returned to their physician within six months with new symptoms, and nearly 40% of those patients had to see a specialist for their health issues.
The cause of long-term COVID-19 health impacts remains as yet unknown. Lingering problems may be due to injury to organs including the lungs, heart and brain. Those affected may be suffering a relapse or reinfection – whether from hidden reservoirs of virus in the body or from a new infection – or their immune system may be responding abnormally, exhibiting either a reduced response or a prolonged inflammatory one. Some symptoms may simply be the result of changes in a patient’s physical condition due to prolonged inactivity or post-traumatic stress.
But, based on the findings to date, long COVID may be emerging as the world’s next health crisis.