COVID-19 does not affect the lung function of young adults, according to the first study of its kind.
Research led by Dr Ida Mogensen, a post-doctoral fellow at the Karolinska Institute, Stockholm, Sweden, found that even patients with asthma did not show a statistically significant deterioration in lung function.
However, there were slightly lower measurements for forced expiratory air volume in one second (FEV1).
This study, which will be presented to online European Respiratory Society International Congress today, follows another study that was presented on Sunday, which showed that the lung function in children and adolescents was also unimpaired after COVID-19, apart from those who experienced a severe infection.
Dr Mogensen and her colleagues examined data from 661 young people with an average age 22 years who were part of a large study that enrolled children born between 1994 and 1996 in Stockholm.
The examinations at the COVID-19 follow-up took place between October 2020 and May 2021 and included lung function and eosinophils.
Out of the 661 participants, 178 (27%) had antibodies against SARS-CoV-2.
The researchers measured FEV1, forced vital capacity (FVC) and FEV1/FVC ratio, which is an indicator of narrowed airways.
They calculated the changes in lung function between the period before the pandemic and during the pandemic and went on to compare the percentage change with participants who had not been infected.
Dr Mogensen said: “Our analysis showed similar lung function irrespective of COVID-19 history.
“When we included 123 participants with asthma in the analysis, the 24% who had had COVID-19 tended towards having a slightly lower lung function, but this was not statistically significant.”
There was no difference in lung function among patients who had had COVID-19 when it came to eosinophils, indicators of inflammation, allergy responses or use of inhaled corticosteroids.
“These results are reassuring for young adults,” said Dr Mogensen. “However, we will continue to analyse data from more people. In particular, we want to look more closely at people with asthma as the group in this study was fairly small. We are also curious as to whether the length of time after the infection is important, as well as the severity of disease and symptoms.”
The second study, presented by Dr Anne Schlegtendal, a specialist in paediatric and adolescent medicine and paediatric pulmonology at University Children’s Hospital, Ruhr-University-Bochum, Germany, looked at the long-term effects of COVID-19 infection between August 2020 and March 21 in 73 children and adolescents aged between five and 18 years.
She and her colleagues carried out lung function tests between two weeks and six months following COVID-19 infection and compared the results with a control group of 45 children who had not been infected with the coronavirus but may have had some other infection.
In the COVID-19 group, 19 children and adolescents had persistent or new symptoms following infection; eight reported at least one respiratory symptom, six of whom suffered ongoing breathing problems and two had a persistent cough. Two of these eight patients showed abnormal lung function.
When these were compared with the control group, there was no statistically significant difference in the frequency of abnormal lung function at 28% compared to 16% in the COVID group.
“However, further analysis revealed a reduction in the volume of air in the lungs that can be exhaled after a deep breath – forced vital capacity – in patients who had suffered a severe infection, whether COVID-19 or some other infection,” said Dr Schlegtendal.
“These findings should offer some reassurance to children, adolescents and their families. Severity of infection proved to be the only predictor for mild lung function changes and this is independent of a COVID-19 infection.
“The discrepancy between persistent breathing problems and normal lung function suggests there may be a different underlying cause, such as dysfunctional breathing, which is a problem that has also been identified in adults.”
Abstract no: OA4053: Lung function before and after COVID-19 infection in young adults”, by Ida Mogensen et al. Presented in session, Respiratory function after COVID-19 and mechanical ventilation at 16:30-18:00 CEST on 7 September 2021.
Abstract no: OA1303: Anne Schlegtendal et al. Pulmonary function in children and adolescents after COVID-19. 5 September 2021.
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