It is known that having COVID-19 can leave after-effects. Some last a few weeks. Others more than a year. But how many people actually have Prolonged COVID or long-term COVID is still under study. A new work carried out in the Netherlands and published in the prestigious magazine The Lancet revealed that one in eight adults (12.7%) infected with COVID-19 experience long-term symptoms.
The study was conducted by researchers at the University of Groningen and Radboud University Medical Center in the Netherlands.It provided one of the first comparisons of long-term symptoms after coronavirus infection with symptoms in an uninfected population. It also measured symptoms in individuals both before and after COVID-19 infection.
The inclusion of uninfected populations allows for a more accurate prediction of the long-term prevalence of COVID-19 symptoms, as well as a better identification of the main symptoms of Prolonged COVID. “There is an urgent need for data that informs the scale and extent of long-term symptoms experienced by some patients following COVID-19 illness,” said Professor Judith Rosmalen of the University of Groningen, lead author of the study.
“Neverthelessmost previous research on prolonged COVID has not looked at the frequency of these symptoms in people who have not been diagnosed with COVID-19 or looked at individual patient symptoms prior to COVID-19 diagnosis.”he warned.
Dr. Rosmalen added: “The focus of our study examines the symptoms most frequently associated with Prolonged COVID, including respiratory problems, fatigue, and loss of taste and/or smell, both before diagnosis of COVID-19 and in people who have not been diagnosed with it. This method allows us to take into account pre-existing symptoms and symptoms in uninfected people to offer an improved working definition for Long-Term COVID-19 and provide a reliable estimate of the likelihood of Long-Term COVID-19 occurring in the general population.”
In this new study conducted in the Netherlands, researchers collected data by asking participants in the population-based Lifelines COVID-19 cohort to regularly fill out digital questionnaires about 23 symptoms commonly associated with Prolonged COVID.
The questionnaire was sent 24 times to the same individuals between March 2020 and August 2021, meaning that participants who had COVID-19 during this time were infected with the Alpha variant of the coronavirus or earlier variants. Most of the data was collected before the COVID-19 vaccination plan in the Netherlands, so the number of vaccinated participants was too small to analyze in this study.
Participants were recorded as positive for COVID-19 if they had a positive test or medical diagnosis of COVID-19. Of the 76,422 participants, 4,231 (5.5%) participants who had COVID-19 were matched with 8,462 controls based on gender, age, and when they completed questionnaires indicating a diagnosis of COVID-19.
The researchers found that several symptoms were new or more severe three to five months after having COVID-19, compared to symptoms prior to COVID-19 diagnosis and to the control group, suggesting that these symptoms may be considered the core symptoms of long COVID.
The main symptoms recorded were chest pain, shortness of breath, pain when breathing, sore muscles, loss of taste and/or smell, tingling in the hands/feet, a lump in the throat, feeling hot and cold alternately, heaviness in the arms and/or legs and general tiredness. The severity of these symptoms stabilized three months after infection, with no further decline. Other symptoms that did not significantly increase three to five months after COVID-19 diagnosis included headache, itchy eyes, dizziness, back pain, and nausea.
Study first author Aranka Ballering said: “These core symptoms have important implications for future research as they can be used to distinguish between post-COVID-19 condition and non-COVID-19 related symptoms.”
Of study participants who had submitted data on pre-COVID symptoms, the researchers found that 21.4% (381/1,782) of COVID-19 positive participants, compared to 8.7% (361/4,130) from the control group, experienced at least an increase in central symptoms of moderate severity 3 months or more after coronavirus infection. This implies that in 12.7% of COVID-19 patients their new or severely increased symptoms three months after COVID can be attributed to the infection.
“By looking at symptoms in an uninfected control group and in individuals both before and after coronavirus infection, we were able to account for symptoms that might have resulted from non-infectious health aspects of the pandemic, such as stress caused because of the restrictions and the uncertainty,” said Ballering. “The post-COVID-19 condition, Prolonged COVID, is an urgent problem with a growing number of human victims. Understanding the core symptoms and prevalence of post-COVID-19 in the general population represents an important step forward in our ability to design studies that can ultimately inform successful health responses to long-term symptoms of COVID-19. COVID-19”, he highlighted.
The authors acknowledge some limitations of the study. This study included patients infected with the Alpha variant or earlier variants and has no data on people infected during the period when the Delta or Omicron variants were causing the most infections. Furthermore, due to asymptomatic infection, the prevalence of COVID-19 in this study may be underestimated. Another limitation of this study is that, since the beginning of the data collection, other symptoms have been identified, such as brain fog, as potentially relevant to a definition of Prolonged COVID, but this study did not look at these symptoms. Additionally, the study was conducted in one region and did not include an ethnically diverse population.
Professor Judith Rosmalen pointed out that “Future research should include mental health symptoms (for example, symptoms of depression and anxiety), along with other post-infectious symptoms that we were unable to assess in this study (such as brain fog, insomnia, and post-performance malaise). . We were unable to investigate what might cause any of the symptoms seen after COVID-19 in this study, but we hope that future research may provide insight into the mechanisms involved. Also, due to the timing of this study, we were unable to assess the effect of vaccination against COVID-19 and different variants of the coronavirus on symptoms of long-term COVID. We hope that future studies will provide answers about the impact of these factors.”
In a linked comment on the paper posted on The LancetProfessor Christopher Brightling and Dr Rachael Evans, from the University of Leicester Institute of Lung Health (who were not involved in the study), said: “This is a big improvement on previous estimates of COVID prevalence. as it includes an uninfected matched group and takes into account symptoms prior to COVID-19 infection. The pattern of symptomatology observed by Ballering and colleagues was similar to previous reports, with fatigue and shortness of breath among the most common symptoms, but interestingly other symptoms such as chest pain were more of a feature in those with long COVID. versus uninfected controls. The case definition of Long COVID, Brightling and Evaens opined, needs to be further improved, potentially to describe different types of Long COVID, for whom a better mechanical understanding is essential.”