In a study published Tuesday in the journal Cell, the U.S-based team said it had conducted a deep multiomic, longitudinal investigation of more than 200 COVID-19 patients from the point of their initial diagnosis to convalescence two to three months later.
Multiomics are where the data sets of different omic groups are combined during an analysis. Omics refers to branches of biology whose names end in -omic, like genomics.
The study – integrated with clinical data and patient-reported symptoms – resolved four factors at the time of initial diagnosis, including Type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia and specific autoantibodies.
In patients with gastrointestinal long COVID, T cells uniquely presented a cytotoxic post-acute expansion.
Analysis of symptom-associated immunological signatures showed coordinated immunity polarization – in which immune cells adopt distinct programs and perform specialized functions in response to specific signals – into four health condition subtypes exhibiting divergent acute severity and long COVID.
“We find that immunological associations between [long COVID] factors diminish over time leading to distinct convalescent immune states,” the group wrote, noting that the detectability of most long COVID factors at diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions.
Jim Heath, the principal investigator of the study and president of Seattle’s Institute for Systems Biology, told The New York Times that 37% of the patients – ages 18 to 89 – had reported three or more symptoms of long COVID two or three months post-infection. Twenty-four percent reported one or two symptoms, and 39% reported no symptoms.
Patients – many of whom were hospitalized – were surveyed for symptoms associated with long COVID, and researchers analyzed blood and nasal swabs incrementally.
Of those reporting three or more symptoms, 95% had one or more of the four biological factors identified in the study when they were diagnosed.
Heath told the publication that autoantibodies were associated with two-thirds of the cases of long COVID. The group corroborated some of its findings in a separate group of 100 patients and compared results to data from 457 healthy people.
“We did this analysis because we know patients will go to physicians and they’ll say that they’re tired all the time or whatever and the physician just tells them to get more sleep. That’s not very helpful. So, we wanted to actually have a way to quantify and say that there’s actually something wrong with these patients,” he explained.
The study authors cautioned that the findings were exploratory and that more research would need to be done.
In a report, researchers in Israel have said that data from people infected with the virus early in the pandemic suggest vaccination can help to reduce the risk of long COVID.
According to the Centers for Disease Control and Prevention (CDC), people can experience long COVID conditions for four or more weeks after first being infected with the virus. These conditions can present as different types and combinations of health problems.
Some people who have had severe illness with COVID-19 experience multiorgan effects or autoimmune conditions, and children can experience multisystem inflammatory syndrome (MIS).
The agency said symptoms – excluding other types of post-COVID conditions that tend to occur in those who have had severe illness – for anyone who has had COVID-19 can include difficulty breathing, brain fog, joint or muscle pain, sleep problems, mood swings, change in menstrual period cycle and change in smell or taste.
As of July, long COVID conditions can be considered a disability under the Americans with Disabilities Act (ADA).
The best way to prevent conditions of long COVID is to prevent COVID-19 illness.