One in eight adults (12.7 per cent), who are infected with SARS-CoV-2, experiences long term symptoms because of it, suggests a large Dutch study published in The Lancet.
WHY IS THIS STUDY IMPORTANT CONSIDERING THERE HAVE BEEN EARLIER STUDIES ON THE SAME SUBJECT?
The study provides one of the first comparisons of long-term symptoms after SARS-CoV-2 infection (often called “long COVID”) with symptoms in an uninfected population as well as measuring symptoms in individuals both pre- and post-COVID-19 infection. Most previous research into long COVID has not looked at the frequency of these symptoms.
The study looks at the symptoms most often associated with long COVID, including breathing problems, fatigue and loss of taste and/or smell, both before a COVID-19 diagnosis and in people who have not been diagnosed with COVID-19. This method allowed them to take pre-existing symptoms and symptoms in non-infected people into account to offer an improved working definition for long COVID and provide a reliable estimate at how likely long COVID-19 is to occur in the general population.
WHAT THE DATA SAYS
Researchers collected data by asking participants to regularly 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 meaning participants who had COVID-19 during this time were infected with the SARS-CoV-2 alpha-variant or earlier variants.
Of the 76,422 participants, 4,231 (5.5 per cent) 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 researchers found that several symptoms were new or more severe, three to five months after having COVID-19, compared to symptoms before the diagnosis, suggesting these symptoms can be viewed as the core symptoms of long COVID. The researchers found that 21.4 per cent (381/1,782) of COVID-19-positive participants, compared to 8.7 per cent (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 per cent of COVID-19 patients, their new or severely increased symptoms three months post-recovery, can be attributed to SARS-CoV-2 infection.
WHAT ARE THE LIMITATIONS OF THE DATA?
Dr Vikas Deswal, Senior Consultant, Internal Medicine, Medanta Hospital, Gurgaon, said, “We need to see the variant-specific data with respect to long COVID. Different variants will result in different types of COVID based on the symptoms and severity of the disease. Every variant may not result in long COVID. Delta resulted in long COVID and so did Omicron. The incidence of long COVID depends entirely on the variant. With respect to Omicron, patients developed long COVID three months from the onset of their infection. This period of lethargy and fatigue tended to last another two months.”
Most of the data was collected before the COVID-19 vaccine rollout in The Netherlands, so the number of vaccinated participants was too small to analyse in this study. This study included patients infected with the alpha variant or earlier variants of SARS-CoV-2 and has no data from people infected during the period when the Delta or Omicron variants were causing most infections. Additionally, due to asymptomatic infection, the prevalence of COVID-19 in this study may be underestimated. Another limitation to this study is that since the beginning of data collection other symptoms, such as brain-fog, have been identified as potentially relevant for a definition of long COVID but this study did not look at these symptoms.
WHAT ARE THE CORE SYMPTOMS AS IDENTIFIED IN THE STUDY?
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.
Other symptoms that did not significantly increase three to five months after a COVID-19 diagnosis, included headache, itchy eyes, dizziness, back pain and nausea, according to The Lancet report. “There is an urgent need for data informing the scale and scope of the long-term symptoms experienced by some patients after COVID-19 illness,” Prof Judith Rosmalen from the University of Groningen, lead author of the study, said in the report.
Classifying the symptoms he observed among his patients, Dr Deswal said, “These were chronic issues such as breathlessness, eye problems, muscle weakness, dementia, weight loss, concentration issues and disturbed sleep cycles. Long COVID actually affects the overall health and well-being of a person. It affects the patient’s neurological systems, kidneys, gastrointestinal tracts, the neuro-muscular and musculo-skeletal systems. Many develop dizziness, nausea, anxiety and lose their ability to smell and taste. Many began having irregular heart beats and all this takes a toll, causing them panic attacks and low grade depression. The best thing to do during this time is to take it easy, breathe, meditate, and do light exercises. This will help you get through long COVID, regular exercise, a nutritious diet, an activity that calms the mind. Also keep consulting your doctor and how to feel better, what more you can do. Usually long COVID has a window for five to six months. But again that depends entirely on the individual.”
HOW CAN THE STUDY HELP IN BETTER PANDEMIC MANAGEMENT
As Prof Judith Rosmalen said in his report, “Future research should include mental health symptoms (depression and anxiety symptoms), along with additional post-infectious symptoms that we could not assess in this study (such as brain fog, insomnia, and post-exertional malaise). Furthermore, due to the timing of this study we were unable to assess the effect of COVID-19 vaccination and different SARS-CoV-2 variants on long COVID symptoms. We hope future studies will provide answers on the impacts of these factors.”