The lungs of some Covid-19 patients remain intact. Age seems to play a key role in protecting the lungs, say two new studies.

According to new research presented at the ‘virtual’ European Respiratory Society International Congress, COVID-19 infection does not appear to impair the lung function of young individuals.

Researchers led by Dr Ida Mogensen, a post-doctoral fellow at the Karolinska Institute in Stockholm, Sweden, discovered that even patients with asthma did not experience a statistically significant decline in lung function, despite a trend toward slightly lower measurements of the amount of air they could exhale.

A second study presented at the congress on Sunday demonstrated that, with the exception of individuals who had a severe illness, the lung function of children and adolescents was also unimpaired following COVID-19 infection.

Dr Mogensen and her colleagues obtained data from 661 young adults with an average age of 22 years who were participating in a large study that monitored children born in Stockholm between 1994 and 1996. Between 2016 and 2019, the most recent pre-pandemic clinical assessment was conducted. The COVID-19 follow-up examinations were conducted between October 2020 and May 2021. The researchers collected data on lung function, inflammation, and white blood cells called eosinophils, which are a type of white blood cell.

178 (27 percent) of the 661 participants exhibited antibodies against SARS-CoV-2, indicating infection. The researchers determined FEV1, FVC (forced vital capacity, which is the amount of air in the lungs that can be exhaled after taking the deepest breath possible), and the FEV1/FVC ratio, which is a marker of narrower airways. They calculated changes in lung function between the pre-and post-pandemic periods. They then compared the percentage change to that of uninfected participants.

There was no difference in lung function between COVID-19 patients and controls in terms of eosinophils, a marker of inflammation, allergic reactions, or usage of inhaled corticosteroids.

“These results are reassuring for young adults. However, we will continue to analyze 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 paediatric and adolescent medicine specialist and paediatric pulmonologist at University Children’s Hospital, Ruhr-University-Bochum, Germany, examined the long-term effects of COVID-19 infection in 73 children and adolescents aged 5 to 18 years between August 2020 and March 21.

She and her colleagues evaluated lung function in children two weeks to six months after infection with COVID-19 and compared the results to a control group of 45 children who were not infected with the coronavirus but may have had another illness. The subjects had varying degrees of illness severity. Severe infections were defined as those that resulted in dyspnea, a fever greater than 38.5 degrees Celsius for more than five days, bronchitis, pneumonia, or hospitalization for more than a day.

19 children and adolescents in the COVID-19 group experienced chronic or new symptoms following SARS-CoV-2 infection; 8 had at least one respiratory symptom, 6 had continuing breathing difficulties, and 2 had a persistent cough. In two of these eight patients, abnormal lung function was seen.

“When we compared the COVID-19 patients with the control group, we found no statistically significant differences in the frequency of abnormal lung function. They occurred in 16% of the COVID-19 group and 28% of the control 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-10 or some other infection,” said Dr Schlegtendal.

The study’s limitations include the small sample size, the fact that participants were recruited at a single hospital, the fact that patients self-reported their symptoms, and a lack of data on long-term results in the control group. Additionally, the COVID-19 group excluded people who experienced severe respiratory difficulties during the acute phase of the infection.

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