One of them was carried out by scientists from the Karolinska Institute with the involvement of 661 residents of Stockholm, of whom 178 suffered COVID-19. The average age of the participants was 22 years. All volunteers participate in an ongoing study that assesses the health status of people born between 1994 and 1996 each year. Scientists took advantage of pre-pandemic clinical data from all participants, and from October 2020 to May 2021, they assessed lung function using spirometry, and also determined the level of inflammatory markers.
Key measures of lung function – forced expiratory volume in 1 second (FEV1) and maximum volume of air that can be inhaled or exhaled (VC) – were similar for all participants, regardless of whether they had COVID-19. There were no differences in the levels of inflammatory markers.
The scientists then identified a subgroup of 123 participants with diagnosed asthma, 24% of whom had coronavirus confirmed. Spirometry showed a slight decrease in lung function in asthmatics who underwent COVID-19, but these indicators were not statistically significant, the study authors emphasized.
The second small study was conducted by specialists from the University Children’s Hospital of the Ruhr University in Bochum with the participation of 21 children from 5 to 18 years old who suffered from COVID-19. The control group included 45 children who did not have COVID-19, but they could get another respiratory infection.
The researchers performed a series of lung function tests on all participants between two weeks and six months after infection and compared them with the control group. As a result, experts did not find statistically significant differences in the frequency of the observed deterioration in lung function.
“Violations were observed in 16% of patients after COVID-19 and 28% of the control group. However, further analysis showed that the decrease in forced expiratory volume was approximately the same both after coronavirus and after any other infection, ”the scientists said, noting that the findings require confirmation in larger studies.