Long COVID poses a conundrum for doctors and researchers. Representing a wide range of new, recurrent, or persistent health conditions that occur approximately one month after initial infection, it may affect 20-30% of patients after recovery from even mild illness and approximately half of COVID-19 patients. 19 who had to be hospitalized.
Over 200 symptoms are associated with long COVID, but there is no universal clinical case definition.
Long-haulers often don’t know what to do about their persistent symptoms, which can include fatigue, shortness of breath, memory problems and gastrointestinal symptoms. Many different organ systems are involved, said Akiko Iwasaki, PhD, professor of immunobiology at Yale University and principal investigator at the Howard Hughes Medical Institute.
“We really need guidance so doctors can properly diagnose long COVID because obviously not all patients have all of these symptoms,” Iwasaki said during a recent episode of “AMA COVID-19 Update.”
Long COVID likely includes multiple diseases under one umbrella, Iwasaki said. The task before us is to dissociate and disentangle the conditions.
The causes of long COVID have eluded clinicians and researchers, but several hypotheses exist.
Persistent virus or viral remnants in tissues, such as viral RNA or protein, could trigger chronic inflammation. Another hypothesis is autoimmunity, Iwasaki noted. Acute respiratory infection can induce autoimmune diseases in some patients. Once that happens, it’s very hard to go back. “And that could be happening in a subset of long COVID patients.”
Dysregulated gut microbiome, dysbiosis, and latent reactivation of viruses such as Epstein-Barr are other possibilities. “Right now we’re at the hypothesis stage,” she said.
Find out what doctors want patients to know about the long COVID.
Research so far suggests the long COVID could fall into “two bins,” Iwasaki said.
There’s the patient who had a severe case of COVID, was hospitalized and then discharged. Long COVID appeared in about half of these patients.
Long COVID has also been observed in patients with mild or asymptomatic infections who develop symptoms over time, within three months of infection. The prevalence in this group tends to be between 5% and 30%. “They vary because we don’t have a universal definition of long COVID,” Iwasaki said.
British researchers have also found definitive physical changes in long COVID patients. Compared to uninfected matched controls, they have a greater reduction in gray matter thickness and overall brain size, and greater changes in markers of tissue damage in regions connected to the primary olfactory cortex.
It’s unclear what causes these types of reductions in brain mass, “but I believe inflammation is involved,” Iwasaki said.
There is not enough data available at present to advise doctors on treatment. “What we really need to do is understand these different endotypes that underlie the disease called long COVID,” Iwasaki suggested.
Find answers to common questions patients have about the long COVID.
Iwasaki has joined other public health experts in releasing a roadmap on strategies for living with COVID-19. Long COVID was one of 12 key areas.
The roadmap foresees the creation of a task force to coordinate inter-agency activities. “We also need to create scientific and regulatory responses to characterize and then count very long COVIDs and also understand the basic pathogenesis of the disease so that we can start planning clinical trials based on this understanding,” he said. she declared.
Physicians need a consensus guideline for interdisciplinary models of care for the clinical treatment and management of long COVID. “And of course we have to make sure that adequate health and social support is provided to patients,” Iwasaki said.
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