BMC pulmonary medicineNov 6, 2025

Lung Health in Adults and Kids After Mild COVID-19

Updated Jan 1, 2026

Abstract

In a cohort of 110 patients, 50% of adults and 85% of children exhibited impaired lung function after mild COVID-19.

Pulmonary function tests revealed that 45 adults (50%) and 17 children (85%) had at least one abnormal lung function measure, primarily affecting the lung clearance index.
Follow-up assessments showed that 69.2% of children and 83.3% of adults with initial lung function impairment still had abnormal values approximately 5 months post-infection.
Specific respiratory symptoms, such as dyspnoea and chest pain, were associated with lower values in lung function tests.
40.3% of patients with abnormal lung function and 43.5% with normal function had detectable pathogens in their respiratory samples.
Most patients experienced improvement in pulmonary function within 3 months, but critical impairment may not be captured by standard spirometry and diffusion capacity tests.

Simplified

BACKGROUND: Although the majority of patients suffering from COVID-19 (coronavirus disease 2019) did not require hospitalization, data on the persistence of pulmonary sequelae after a mild SARS-CoV-2 (severe acute respiratory disease coronavirus 2) infection in patients without pre-existing respiratory diseases are virtually missing.

METHODS: Pulmonary function (spirometry, diffusion capacity for carbon monoxide (DLCO), and lung clearance index (LCI)) was assessed 4-12 weeks after SARS-CoV-2 infection in non-hospitalized patients aged 6-60 years. Acute and persisting COVID-19-related respiratory symptoms were ascertained, and the presence of other acute respiratory infection pathogens was checked via a multiplex-PCR approach from pharyngeal swabs. Participants with impaired lung function underwent a follow-up examination 3 months later. To complement the initial analysis, a retrospective z-score analysis of lung function parameters was conducted.

RESULTS: 110 patients (90 adults, 20 children) were included. In 45 adults (50%) and 17 children (85%), at least one pulmonary function test indicated an impaired lung function, particularly the LCI. Despite overall improvement between baseline and follow-up, 9 of 13 (69.2%) children and 35 of 42 (83.3%) adults with initial impairment still showed abnormal values about 5 months post SARS-CoV-2 infection. Specific respiratory symptoms were linked to lower spirometry and DLCO values. In 25 patients (40.3%) with abnormal lung function, and in 20 participants (43.5%) with normal pulmonary function, pathogens were detected at t. The retrospective z-score analysis closely mirrored the initial findings. 1

CONCLUSION: Critical pulmonary impairment after mild COVID-19 is rarely detected by spirometry and DLCO but may affect the LCI. Within 3 months, impaired pulmonary function improved in most patients. Children were less affected by severe pulmonary sequelae and respiratory complaints than adults. Complaints like dyspnoea or chest pain may be an early indicator of lung function impairment, suggesting that further diagnostic tests for treatable post-COVID-19 complications may be needed. Additionally, PCR-based screening for additional respiratory pathogens may help avoid misinterpretation of lung function results post SARS-CoV-2 infection.

TRIAL REGISTRATION: Retrospectively registered in ClinicalTrials.gov (ID NCT06318208) and German Clinical Trials Register (ID DRKS00030025).

Abstract

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