One in eight adults who suffer from COVID-19 go on to experience long-COVID, according to a new Dutch study published today.
The study, published in *The Lancet* is one of the first to compare long-term symptoms after SARS-CoV-2 infection with symptoms in an uninfected population, and to measure symptoms in individuals both pre- and post-COVID-19 infection.
The researchers say including uninfected populations enables a more accurate prediction of long-term COVID-19 symptom prevalence as well as improved identification of the core symptoms of long COVID.
They collected data by asking participants of the population-based Lifelines COVID-19 Cohort to fill out digital questionnaires on 23 symptoms commonly associated with long COVID.
The questionnaire was sent out 24 times to the same individuals between March 2020 and August 2021 and most of the data was collected before the COVID-19 vaccine rollout in The Netherlands.
Out of 76,422 participants, 4,231 (5.5%) participants who had COVID-19 were matched to 8,462 controls taking account of sex, age and time of completing questionnaires that indicated a COVID-19 diagnosis.
The research team found that several symptoms were new or more severe three to five months after having COVID-19, compared to symptoms before a COVID-19 diagnosis and to the control group.
These were chest pain, difficulties breathing, pain when breathing, painful muscles, loss of taste and/or smell, tingling hands/feet, a lump in throat, alternately feeling hot and cold, heavy arms and/or legs and general tiredness.
The severity of these symptoms plateaued at three months after infection with no further decline.
First author Aranka Ballering said: “These core symptoms have major implications for future research, as these symptoms can be used to distinguish between post COVID-19 condition and non-COVID-19-related symptoms.”
Out of the study participants who had submitted pre-COVID symptom data, the researchers found that 21.4% (381/1,782) of COVID-19-positive individuals, compared to 8.7% (361/4,130) of the control group, experienced at least one increased core symptom at moderate severity three months or more after SARs-CoV-2 infection.
This implies that in 12.7% of COVID-19 patients their new or severely increased symptoms three months post-COVID can be attributed to SARS-CoV-2 infection.
Ms Ballering said: “By looking at symptoms in an uninfected control group and in individuals both before and after SARS-CoV-2 infection, we were able to account for symptoms which may have been a result of non-infectious disease health aspects of the pandemic, such as stress caused by restrictions and uncertainty.
“Post-COVID-19 condition, otherwise known as long COVID, is an urgent problem with a mounting human toll. Understanding the core symptoms and the prevalence of post-COVID-19 in the general population represents a major step forward for our ability to design studies that can ultimately inform successful healthcare responses to the long-term symptoms of COVID-19.”
The authors acknowledge some limitations in the study, including that its data is from patients infected with the alpha variant or earlier variants of SARS-CoV-2 and not from people infected during the period when the delta or omicron variants were causing most infections.
Lead study author Professor Judith Rosmalen, from the University of Groningen, said future research should include mental health symptoms, as well as post-infectious symptoms that its research did not assess.
Ballering AV, van Zon SKR, olde Hartman TC et al. Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study. *Lancet* 5 August 2022; doi: 10.1016/ S0140-6736(22)01214-4
Leave a Reply