Among the many complicated aspects of Covid-19, long Covid is one of the most puzzling.
Long Covid describes the wide range of symptoms—including respiratory, neurological and heart conditions—that patients who had Covid-19 still report months after their Covid-19 diagnosis. The variety and intensity of the symptoms are so broad that the main way long Covid is diagnosed is by ruling out other options.
But a new study, the largest so far on long Covid, published today in The Lancet, is at least beginning to identify some of the most common symptoms of long-term Covid-19 impact, as well as understand the evolution of such symptoms both six months and a year after the initial infection.
The study, conducted by the Medical University of Beijing, and the China-Japan Friendship Hospital of Beijing with the Jin Yin-tan Hospital of Wuhan, followed more than 1,200 hospitalized Covid-19 patients for a year after the onset of their symptoms. The patients, whose median age was 59 and 53% of whom were male, went back to the hospital for six-month and 12-month follow-up visits, where they had to answer questionnaires about their symptoms and how they impacted their quality of life, as well as complete some testing.
The finding was striking: Six months after developing Covid-19 symptoms, 68% of patients had at least one lingering symptom, and a year after the disease onset half of them still did. The most common of these symptoms were fatigue and muscle weakness, which affected 52% of patients after six months, and 20% after a year. Women were more likely to suffer from fatigue and weakness, as were people of both sexes who had been treated with corticosteroids to reduce inflammation during their Covid-19 hospitalization.
A third of patients, too, reported having respiratory problems a year after their initial illness, especially shortness of breath—a higher percentage than after six months after the visit, when about a fourth of them did. The study also measured lung capacity, beyond perceived shortness of breath, finding that after a year 20% to 30% of the patients who had been moderately ill, and 54% of those who had been gravely ill, still hadn’t gained back full lung capacity.
Pain and discomfort were also still pretty common among long Covid-19 patients: 29% of them reported the symptoms after a year, slightly more than the 26% that reported them after six months.
By giving doctors more information about the most common symptoms of long Covid, this study can help identify potential patterns—such as the link between corticosteroid drugs and fatigue. Those can be used to inform therapy during hospitalization or following the release, with the goal of reducing the incidence or severity of long-term symptoms.