Almost half of all people with mild coronavirus cases still have at least one symptom six months after recovering, a new Israeli study found.
Moreover, in some cases, these symptoms either weren’t present initially or disappeared and then came back.
Among the 46 percent of patients who reported persistent symptoms, the most common was fatigue, followed by an altered sense of smell and taste, and then breathing problems.
The study surveyed 103 patients over the age 18 who were infected in March or April 2020 and were never hospitalized. It was published this week in the journal “Clinical Microbiology and Infection.”
The study began almost a year ago, when respondents were asked about their initial symptoms. The researchers kept in touch by phone until the symptoms disappeared. Then, six months later, they contacted all the patients again.
“There were some we interviewed several times because their symptoms persisted,” said Prof. Masha Niv of Hebrew University, one of the few Israelis who studies the sense of taste. “There were others whose symptoms disappeared quickly. But half a year later, we contacted them all.”
They managed to reach 99 of the original 103 participants and were surprised by what they discovered.
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“There were some who thought they had recovered, but a few months later, new symptoms appeared,” Niv said. “For instance, fatigue. Of the 99 respondents, 23 said that half a year later, they still experienced fatigue. But for 17 of these, this was a new symptom that hadn’t appeared earlier.”
The interviewers asked the patients about specific symptoms and also invited them to detail additional symptoms. Fatigue wasn’t one of the symptoms the researchers specifically asked about, “but it was apparently noteworthy enough after half a year to make people report it,” Niv said.
Regarding breathing problems, “eight reported that they still experience them, and of these, six said it was new.” Six patients also reported memory problems after six months, “and for all of them this was a new problem that didn’t exist initially,” she said.
The researchers also asked which symptoms had appeared first. The most common were headaches (44 percent), fever (41 percent), muscle pain (39 percent) and a dry cough (38 percent). Only at a later stage did people report losing their sense of taste and smell.
Among most of the patients, all symptoms disappeared within three weeks, but some symptoms lasted longer than others. Fever was the shortest lived, usually disappearing within about six to nine days. A disrupted sense of taste and smell – smelling something that doesn’t exist or something other than what’s present – was the longest lived, usually persisting for about 17 to 20 days.
But for a minority of patients, certain symptoms lasted much longer than three weeks. “Regarding taste and smell, for instance, we found that among 10 to 15 percent of the people, the disruption of their sense of taste and smell hadn’t resolved even after 200 days,” Niv said.
Most people do eventually recover from the virus, she stressed, “but it’s important for people to know what to expect, even if we don’t know how long it will take. We also know there is sometimes post-virus damage from other viruses, and it can take time before it resolves.”
Initially, coronavirus patients’ reports of a disrupted sense of taste and smell weren’t taken seriously, Niv said. But this is now recognized as a significant symptom of the virus, “and there are huge support groups for this issue.”