London: One in eight adults who are infected with SARS-CoV-2 experience long term symptoms due to COVID-19, according to one of the most comprehensive studies on the viral disease to date published in The Lancet journal on Friday (August 5). The study provides one of the first comparisons of long-term symptoms after SARS-CoV-2 infection, called ‘long COVID’, with symptoms in an uninfected population, as well as those in individuals both pre- and post-COVID-19 infection.
The inclusion of 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.
“There is urgent need for data informing the scale and scope of the long-term symptoms experienced by some patients after COVID-19 illness.” said Professor Judith Rosmalen from the University of Groningen in The Netherlands.
However, most previous research into long COVID has not looked at the frequency of these symptoms in people who haven’t been diagnosed with COVID-19 or looked at individual patients’ symptoms before the diagnosis of COVID-19, said Professor Rosmalen, lead author of the study.
The study looked at the symptoms most often associated with long COVID, including breathing problems, fatigue and loss of taste and smell, both before a COVID-19 diagnosis and in people who have not been diagnosed with the disease.
The 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.
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.
Of 76,422 participants, 4,231 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 a diagnosis and to the control group, suggesting these symptoms can be viewed as the core symptoms of long COVID.
The core symptoms recorded were chest pain, difficulties breathing, pain when breathing, painful muscles, loss of taste or smell, tingling hands and feet, a lump in throat, alternately feeling hot and cold, heavy arms or legs and general tiredness.
The severity of these symptoms plateaued at three months after infection with no further decline, according to the researchers.
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, they 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, said PhD candidate Aranka Ballering, first author of the study.
Of the study participants who had submitted pre-COVID symptom data, the researchers found that 21.4 per cent of COVID-19-positive participants, compared to 8.7 per cent of the control group, experienced at least one increased core symptom at moderate severity 3 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-COVID can be attributed to SARS-CoV-2 infection.
“This is a major advance on prior long COVID prevalence estimates as it includes a matched uninfected group and accounts for symptoms before COVID-19 infection,” said Professor Christopher Brightling and Rachael Evans from the University of Leicester, UK.
The pattern of symptomatology observed by Ballering and colleagues was similar to previous reports with fatigue and breathlessness amongst the commonest symptoms, but interestingly other symptoms such as chest pain were more a feature in those with long COVID versus uninfected controls, the scientists, who were not involved in the study, noted.
The authors acknowledge some limitations in the study as it 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.
Also, due to asymptomatic infection, the prevalence of COVID-19 in this study may be underestimated, the researchers said.
Another limitation to the 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, they added.
(This story has not been edited by NDTV staff and is published from a syndicated feed.)
NDTV – Dettol have been working towards a clean and healthy India since 2014 via the Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity, which is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.