COVID-19 infection does not appear to affect lung function in young adults, study finds

COVID-19 infection does not appear to affect the lung function of young adults, according to a new study presented today (Tuesday) at the “virtual” international congress of the European Respiratory Society.

In the first study to investigate the impact of COVID-19 infection on lung function, researchers led by Dr Ida Mogensen, postdoctoral fellow at the Karolinska Institute in Stockholm, Sweden, found that even Asthma patients did not exhibit deterioration in lung function, although there was a tendency for slightly lower measurements for the amount of air they could forcefully exhale in one second – known as volume d. One-second forced expiratory air (FEV1), which is one of the measures of lung function.

A second study presented to Congress on Sunday showed that lung function in children and adolescents was also not impaired after infection with COVID-19, except for those who suffered severe infection.

The COVID-19 pandemic has raised questions about whether and how the lung is affected after the coronavirus infection clears, especially in young people in the general population with less severe illness. Until now this was not known. “

Dr Ida Mogensen, Postdoctoral Fellow, Karolinska Institute

Dr Mogensen and his colleagues collected information from 661 young people with an average age of 22 who were part of a large study of children born between 1994 and 1996 in Stockholm, and who were followed by researchers since then. The most recent pre-pandemic clinical exam was performed between 2016 and 2019. Follow-up COVID-19 exams took place between October 2020 and May 2021. Data collected included measurements of lung function, inflammation and white blood cells called eosinophils, which are part of the immune system.

Of the 661 participants, 178 (27%) had antibodies to SARS-CoV-2 indicating they had been infected. The researchers measured FEV1, FVC (forced vital capacity, which is the volume of air in the lungs that can be exhaled after the deepest possible breath) and the 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. Then they compared the percentage change with the participants who had not been infected.

“Our analysis showed similar lung function regardless of a history of COVID-19,” said Dr Mogensen. “When we included 123 asthmatic participants in the analysis, the 24% who had COVID-19 tended to have slightly lower lung function, but this was not statistically significant.”

There was no difference in lung function in patients who had had COVID-19 with respect to eosinophils, indicators of inflammation, allergic responses, or use 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 take a closer look at people with asthma because the group in this study was quite small. We are also curious as to whether the length of time after infection is significant, as well as the severity of the disease and symptoms. “

The second study, presented by Dr Anne Schlegtendal, a specialist in pediatric and adolescent medicine and pediatric pulmonology at the Ruhr-University-Bochum Children’s University Hospital, Germany, looked at the long-term effects of the infection. to COVID-19 between August 2020 and March 21 on 73 children and adolescents aged 5 to 18 years.

Dr Schlegtendal said: “Although children and adolescents tend to suffer from less severe symptoms of COVID-19 infection than adults, to date there is only preliminary evidence of the long-term effects. of COVID-19 on lung function in children and adolescents.It is important to assess this given that children around the world will potentially be infected with SARS-CoV-2 as long as vaccines are primarily restricted to adults and children. high-risk groups. “

She and her colleagues performed lung function tests between two weeks and six months after infection with COVID-19 and compared the results with a control group of 45 children who had not been infected with the coronavirus but could have had another infection. The participants had different severity of the disease. An infection was considered serious if patients suffered from shortness of breath, a fever above 38.5 degrees Celsius for more than five days, bronchitis, pneumonia, or had been in hospital for more than five days. ‘a day.

Nineteen children and adolescents in the COVID-19 group had persistent or new symptoms following infection with SARS-CoV-2; eight reported at least one respiratory symptom, of which six had persistent breathing problems and two had a persistent cough. Two of these eight patients presented with abnormal lung function.

“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 group. However, further analysis revealed a reduction in the volume of air in the lungs that can be exhaled after deep breathing – forced vital capacity – in patients who had suffered from severe infection, whether ‘Is it COVID-10 or some other infection,’ said Dr Schlegtendal.

“These results should reassure children, adolescents and their families. The severity of the infection was found to be the only predictor of slight changes in lung function and this is independent of COVID-19 infection. L ‘The gap between persistent breathing problems and normal lung function suggests that there may be a different underlying cause, such as dysfunctional breathing, which is a problem that has also been identified in adults. “

Limitations of the study include the small number of participants, the fact that they were recruited from a single hospital, that patients reported their symptoms, and a lack of information on long-term outcomes in the control group. Additionally, the COVID-19 group did not include people with severe breathing problems during the acute phase of infection.

Anita Simonds, who was not involved in the research, is President of the European Respiratory Society, Honorary Consultant in Respiratory and Sleep Medicine at Royal Brompton Hospital and Professor of Respiratory and Sleep Medicine at NHLI, Imperial College London, UK -United. She said: “The results of these two studies are very reassuring about the impact of COVID infection on lung function in children and young adults. We already know that this group is less likely to suffer from a disease. severe if he does contract the virus, and these studies, which mostly include comparison groups without COVID-19, show that they are also less likely to experience long-term consequences when it comes to lung function.

However, additional research may shed light on the effects for people with asthma or who have a severe respiratory infection, whether it is COVID-19 or another infectious cause. These people may be more vulnerable to long-term effects on lung function and stresses the importance for every eligible person to be vaccinated against COVID-19 in order to reduce the overall spread of the disease. ”

The study is called BAMSE (Swedish abbreviation for “Children, Allergy, Milieu, Stockholm, Epidemiology”). It included 4,089 children born in Stockholm between 1994 and 1996. Questionnaires were sent to participants at regular intervals, asking about respiratory symptoms and medications. When the children were 8, 16 and 24 years old, their lung function was tested and blood samples were taken.