- A new study seeks to advance understanding of long-term COVID.
- It finds that long-term COVID can be divided into three types of conditions, depending on the type of symptoms experienced.
- The study authors also find links between COVID-19 variants, symptoms and long duration of COVID.
As experts try to unravel the jumble of symptoms and long-term effects of what’s collectively known as “long-term COVID,” a new study seeks to shed some light.
Working with data collected in a health study app by personalized nutrition company ZOE, researchers from King’s College London in the UK have begun to uncover some order in the chaos.
The study shows that long-term COVID can be grouped into three symptom cluster types: neurological symptoms, respiratory symptoms, and systemic/inflammatory and abdominal symptoms.
- Neurological symptoms – the most commonly reported long-term COVID symptoms – are anosmia/dysosmia, brain fog, headache, delirium, depression and fatigue. (Loss of taste from COVID is usually due to a loss of smell.)
- Respiratory symptoms include possible damage to the lungs and include severe shortness of breath, palpitations, fatigue, and chest pain.
- Systemic/inflammatory and abdominal symptoms include musculoskeletal pain, anemia, myalgia, gastrointestinal disturbances, malaise and fatigue.
For the study, researchers analyzed data from 336,652 individuals collected by ZOE’s COVID Symptom Study. Of this group, 1,459 reported post-COVID symptoms defined as more than 12 weeks after acute COVID-19 infection.
dr. Jai Marathe of the Boston University School of Medicine in Massachusetts, who was not involved in the study, said: Medical news today“This study definitely improves our understanding of post-COVID syndrome and, more importantly, who is at risk for long-term illness and weakness.”
“Doctors and patients,” noted Dr. Marathe noted, “are both looking for answers about who is at risk of developing COVID for a long time, how long the symptoms will last, what will help the symptoms resolve, etc. While this study does not provide all the answers to these questions, it offers a strong framework to build on.”
The research, which has not yet been peer-reviewed, has been published on the pre-print server medRXiV.
The researchers were also able to begin identifying the symptom clusters associated with SARS-CoV-2 variants and with vaccinations.
dr. Liane S. Canas, corresponding author of the study and postdoctoral research associate at King’s College London, told Medical news today:
“Our results suggest that chest-related symptoms (respiratory cluster) in the UK population were more apparent in unvaccinated patients infected with the original form of the virus [referred to as the “wild” variant].”
“Other,” continued Dr. Canas, “patients with the Alpha or Delta variants have shown a higher incidence of neurological symptoms, such as anosmia and brain fog.”
“Unfortunately, we were unable to robustly evaluate the effect of vaccination for these two variants. For Alpha, we had not vaccinated enough people at the time of infection. For Delta, at the time of infection, we didn’t have enough unvaccinated individuals who developed COVID for a long time,” she said.
Systemic/inflammatory and abdominal conditions were slightly associated with all variants.
“On average,” said Dr. Canas, “the wild-type form of the virus has shown a longer prevalence of symptoms, at 30 weeks, compared to Delta and Alpha at 24 and 25 weeks, respectively.”
“However,” she noted, “since we only analyzed data from individuals with disease longer than 12 weeks, these results are less significant than cluster profiling, and further research would be needed, including the effect of vaccination. would be taken into account.”
“The findings of the study,” said Dr. Marathe, “suggest that individuals struggling with long-term COVID who experienced severe shortness of breath, hoarse voice, loss of smell, fatigue, delirium, anosmia, headache and fever were more likely to [experience] prolonged and severe symptoms.”
“Physicians armed with this information,” she said, “may be able to better advise their patients and expectations for symptom improvement. They can also work on targeted treatment approaches that address the symptom cluster that influences and hopefully improves clinical care for the patients.”
The study authors are still analyzing data related to the Omicron variants, but have shared some early insights.
dr. Canas said: “The initial results have shown that the prevalence of long-term COVID among Omicron variant-infected patients is much lower than that of the other variants.”
An article on ZOE’s study says the odds of getting COVID from Omicron for a long time were 20%-50% lower than other variants, with Omicron cases accounting for only 4.4% of cases studied, compared to 10.8 % of cases of the Delta variant .
dr. Marathe cited other research on the relationship between Omicron variants and long-term COVID:
“Some studies have found a lower risk of developing long-term COVID after COVID-19 infection with the Omicron variant compared to the Delta variant, while others have noted that patients who develop long-term COVID after infection with the Omicron variant have a have less serious illness. This includes the overall reduced symptom severity during acute Omicron infection.”
While a lower percentage of people with COVID-19 infections from Omicron variants develop long-term COVID, the greater infectivity of the strains means more people are infected and thus more people develop long-term COVID.
“While the total number of patients with long-term COVID in the community may be lower, at Boston Medical Center, the number of patients seeking care in the long-term COVID clinic has remained stable throughout the post-delta and post-omicron peaks,” said Dr. Marathe.
In terms of long-term COVID symptoms with recent variants, not much has changed, she said:
“We did not notice a major difference in long-term COVID symptoms between the Omicron variants that circulated during the winter and spring months. Fatigue, shortness of breath, mood disturbances and brain fog were still the most common complaints reported by patients with long-term COVID.
dr. Marathe considered the new study valuable:
“This could pave the way for additional research efforts to evaluate the different pathobiological pathways that may contribute to the development of long-term COVID, and help us more successfully define the condition.”
“I think we still don’t know who is at risk for developing long-term COVID and why they are at risk. As we advance our understanding of this disease, it will help inform strategies related to treatment and prevention of long-term COVID,” she added.