COVID-19 is not associated with impaired lung function in young adults, regardless of whether these individuals have asthma or allergies or use inhaled corticosteroids (ICS). These were among study results published in The Journal of Allergy and Clinical Immunology.

Study researchers compared spirometry taken before vs during the COVID-19 pandemic in study participants selected from the Swedish BAMSE cohort, a population-based group initially comprising 4089 children who were followed since infancy (from 1994 to 1996) for allergies. In the current study, researchers analyzed data from examinations that cohort patients received between 22 to 24 years of age (ie, from 2016 to 2019; referred to as the “pre-COVID-19 examination,” completed by 2270 individuals) and from an examination that was initiated after onset of the pandemic (ie, from 2020 to 2021; referred to as the “COVID-19 examination”).

The COVID-19 examination, done in 2 phases, generated data via a web-based questionnaire completed between August and November 2020 as well as another questionnaire and lung function examination completed between October 2020 and June 2021. The lung function examination included measurements of antibodies against SARS-CoV-2. The full 2-phase examination was completed by 1028 of the 2270 individuals who had completed the pre-COVID-19 examination.  Following the exclusion of participants who had missing prebronchodilatory spirometry data from the pre-COVID-19 or COVID-19 examination, insufficient blood samples, or who were vaccinated against SARS-CoV-2, a total of 853 participants were included in the current study.

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Study researchers used serum levels of SARS-CoV-2 receptor-binding domain-specific immunoglobulin (Ig) G, IgM, and/or IgA (per enzyme-linked immunosorbent assay) to define seropositivity. Mean change in lung function (per forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and FEV1/FVC ratio) in percent of predicted from before to after onset of the pandemic were compared between patients who were seronegative and those who were seropositive. Among seropositive participants, change in lung function was evaluated with respect to allergic sensitization and self-reported use of inhaled corticosteroids (ICS).

Overall, 29% (n=243) of the participants included in the study were seropositive and 71% (n=607) of the participants were seronegative for SARS-CoV-2 antibodies. The majority of the seropositive participants (81%) had SARS-CoV-2–specific IgG antibodies.

Study researchers reported no difference in lung function changes between seronegative and seropositive participants with respect to the following parameters: (1) mean change in FEV1 percentage of predicted value (pp): seropositive group, 0.87% ±4.79% vs seronegative group, 1.03%±4.76%, P =.66; (2) mean change in FVC pp: seropositive group, 1.34% ±4.44% vs seronegative group, 1.29%±4.27%, P =.87; and (3) mean change in FEV1/FVC ratio pp: seropositive group, –0.25% ±3.13% vs seronegative group, –0.13%±3.15%, P =.61. Similar findings were reported among participants with asthma.

A major limitation of the current study included the lack of data on total lung capacity, which prevented researchers from drawing conclusions on restrictive lung function impairment; however, the normal spirometry findings suggest that a significant restrictive impairment is unlikely. Additionally, because seropositivity was used as a marker of prior COVID-19 infection, individuals in whom antibody responses were low or absent were not captured.

“We found no evidence that COVID-19 results in impaired spirometric lung function in a population-based sample of young, healthy adults with mild to moderate disease,” the researchers concluded.  In addition, the study did not find that participants with asthma were more susceptible to long term lung function impairment. These results are “reassuring for patients, health care providers, and public health management during the COVID-19 pandemic,” the researchers noted.


Mogensen I, Hallberg J, Björkander S, et al; BAMSE COVID-19 Study Group. Lung function before and after COVID-19 in young adults: a population-based study. J Allergy Clin Immunol Global. Published online March 30, 2022. doi:10.1016/j.jacig.2022.03.001