A new Dutch study has found that up to one in eight adults exposed to COVID-19 will develop long-term symptoms.
The study, published in the peer-reviewed journal The Lancet, looked at groups of adults diagnosed with COVID-19 as well as those who were not infected, and examined whether they developed new symptoms of disease or worsened.
The authors say their study found that about one in eight patients, or 12.7%, of patients in the general population had long-term symptoms of COVID-19.
Judith Rosmalen, professor of psychosomatic medicine at the University of Groningen and lead author of the study, said in a press release on Thursday that including uninfected people in the research provides a more reliable estimate of the likely duration of COVID in the general population.
The Canadian government, citing the World Health Organization, says between 10-20% of people develop long-lasting COVID.
The main symptoms of long COVID examined for the Dutch study included chest pain, difficulty or painful breathing, muscle aches, loss of taste and smell, tingling in the extremities, a lump in the throat, a feeling hot and cold, heavy arms or legs and general fatigue. .
“There is an urgent need for data informing the magnitude and scope of long-term symptoms experienced by some patients after illness from COVID-19,” Rosmalen said in the statement.
“However, most previous research on long COVID has not looked at the frequency of these symptoms in people who have not been diagnosed with COVID-19 or have looked at the symptoms of individual patients prior to the diagnosis of COVID. -19.”
The researchers began by asking participants in the Lifelines COVID-19 Cohort Study to regularly complete digital questionnaires about 23 symptoms commonly associated with long COVID.
Lifelines is a multigenerational study involving more than 167,000 participants from the population of the North of the Netherlands.
Questionnaires were sent 24 times to the same people between March 2020 and August 2021. The researchers say most of the data was collected before the rollout of COVID-19 vaccines in the Netherlands.
Participants were considered COVID-positive if they either tested positive or had a medical diagnosis.
The average age of the participants was 53.7 years, while 60.8% were women.
Of the 76,422 participants, 4,231 had COVID-19. This group was then matched to 8,462 uninfected people, taking into account gender, age and when a diagnosis of COVID-19 was confirmed in a questionnaire in the positive group.
The study found that 381 of 1,782 COVID-positive participants (21.4%) had persistent symptoms, compared to 361 of 4,130 uninfected (8.7%).
Taken together, this means that in 12.7% of patients, these symptoms can be attributed to COVID-19, the researchers said.
“The post-COVID-19 condition, otherwise known as long COVID, is an urgent problem with a growing human toll,” said PhD student and study first author Aranka Ballering.
“Understanding the core symptoms and prevalence of post-COVID-19 in the general population represents a major advancement for our ability to design studies that can ultimately inform successful healthcare responses to long-term symptoms of COVID-19.
The authors say the study only involved patients infected with previous variants of COVID-19, excluding Delta and Omicron.
The true prevalence of COVID-19 may also be underestimated due to undetected asymptomatic infections, the researchers said.
The study did not examine other longstanding symptoms of COVID that have since been identified as potentially relevant, such as brain fog, the researchers said.
As the study only looked at the northern Netherlands, the authors say the results cannot be generalized to other regions.
Rosmalen says future research should also consider mental health symptoms, such as depression and anxiety, as well as those not included in the study, such as brain fog, insomnia and post-exercise malaise.