INTRODUCTION: Post-acute sequelae of SARS-CoV-2 (PASC) or long COVID may lead to an array of adverse health outcomes in young, otherwise healthy adults, potentially limiting warfighter readiness. This study assessed pulmonary function in Marines to evaluate associations between acute and chronic symptoms of COVID-19 and abnormal spirometry. The data were obtained within the framework of the COVID-19 Health Action Response for Marines (CHARM) study, a larger effort aimed at characterizing PASC in this population.
MATERIALS AND METHODS: Pulmonary function testing (PFT) was performed using portable spirometry on Marine participants in CHARM 2.0 from February 2021 to April 2022. Pulmonary symptoms were characterized as mild, moderate, or severe based on self-report. Participants with symptoms ≥30 days were characterized as having PASC. Individual pulmonary reports were classified as either normal or abnormal. Statistical analyses examined the relationship between pulmonary symptoms and PFT results.
RESULTS: A total of 889 Marines (mean age: 19 years) completed PFTs. Among the 798 COVID-19-positive participants, 61% reported symptomatic infection and 24.7% reported PASC. Data indicated significant reduction in the ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC), forced vital capacity (FVC), the forced expiratory flow generated during the middle half of the FVC measurement (FEF25%-75%), and the peak expiratory flow (PEF) among participants with acute symptoms of dry cough and/or wheezing, as well as chronic symptoms. Despite inverse correlations between several PFT metrics and symptom severity, a significantly greater proportion of participants without a dry cough had more abnormal FVC scores than those with a mild dry cough.
CONCLUSIONS: The chronic effects of COVID-19 in young, healthy adults remain understudied, likely because of the high prevalence of mild or asymptomatic infections, despite recent evidence suggesting these individuals may be at risk for PASC. In this cohort, PEF and PEF% predicted abnormalities were observed but are not consistently included in standard interpretations, representing a potential gap between symptoms and objective findings. These results may provide a useful baseline for assessing future respiratory viral exposures and subclinical lung function changes.
Long Covid