Lung function not affected in children, adolescents post-COVID

COVID-19 does not appear to result in long-term impairment of lung function in children and adolescents, according to two studies presented at ERS 2021.

The first study was conducted in Sweden using the population-based BAMSE cohort which comprises children born in Stockholm between 1994 and 1996. The researchers identified 853 individuals (36 percent male, 24 percent BMI ≥25 kg/m²) who were unvaccinated for COVID-19. To be included, they were required to have spirometry results from before (2016–2019) and during the COVID-19 pandemic (October 2020–May 2021). They also needed to have laboratory test results (eg, allergic sensitization, blood eosinophil count, and fractional exhaled nitric oxide [FeNO]) from the pre-pandemic period and SARS-CoV-2 antibody test results and reports of inhaled corticosteroid (ICS) use from the pandemic period.

Twenty-nine percent (n=243) of the participants were seropositive (IgM >14.42 AU/mL, IgG >25.09 AU/mL, and/or IgA >2.61 AU/mL) against SARS-CoV-2, indicating prior COVID-19 infection. Sex, BMI >25 kg/m², and rates of asthma, elevated blood eosinophil levels, FeNO, allergic sensitization, and reported ICS use were comparable between individuals in the seropositive and seronegative groups.

Change in forced expiratory volume in 1 second (FEV₁) percent predicted did not significantly differ between individuals who were seropositive and seronegative (mean 0.75 percent vs 1.2 percent; p=0.28). [ERS 2021, abstract OA4053]

Change in forced vital capacity (FVC) percent predicted was also comparable between seropositive and seronegative individuals (mean 1.3 percent vs 1.4 percent; p=0.76), as was FEV₁/FVC ratio (-0.013 vs -0.011; p=0.36).

A total of 147 patients had asthma (17 percent), of whom 26 percent (n=38) were seropositive. In this population, there was a trend toward a lower FEV₁ measurement in seropositive compared with seronegative individuals (mean change 0.07 percent vs 2.2 percent; p=0.063).

Among seropositive individuals, lung function did not differ according to blood eosinophil counts, allergic sensitization, ICS use, or FeNO.

“The COVID-19 pandemic has raised questions about if and how the lung is affected after clearance of the coronavirus infection, especially in young people from the general population with less severe disease,” said study author Dr Ida Mogensen from the Karolinska Institute, Stockholm, Sweden.

“Our analysis showed similar lung function irrespective of COVID-19 history,” she continued.

Among patients with asthma, lung function appeared to be slightly lower in those who had COVID-19, though this result was not statistically significant, and there was no evidence of long-term impairment, Mogensen commented. 

While reassuring, more research is warranted. “[W]e want to look more closely at people with asthma as the group in this study was fairly small. We are also curious as to whether the length of time after the infection is important, as well as the severity of disease and symptoms,” she pointed out.

 

Severe infection a trigger?

A smaller single-centre prospective study, this time comprising 73 individuals aged 5–18 years from Germany who had varying levels of COVID-19 disease severity (35.6 percent symptomatic), also found no long-term lung impairment following COVID-19. However, there was evidence of lung function impairment following severe infection, regardless of COVID-19 history.

The patients underwent lung function tests (multiple-breath washout, body plethysmography, and diffusion capacity testing) 2 weeks–6 months after PCR- or antibody-confirmed SARS-CoV-2. They were compared with a control group of 45 individuals with no evidence of COVID-19 but potentially a different infection (31.1 percent symptomatic).

Nineteen patients (27.1 percent) reported new or persistent symptoms after COVID-19, of whom eight had respiratory symptoms. Among those with persistent respiratory symptoms, two had abnormal pulmonary function.

Frequency of abnormal pulmonary function did not significantly differ between the COVID-19 and control group (16.4 percent vs 27.7 percent; odds ratio, 0.54, 95 percent confidence interval, 0.22–1.34). [ERS 2021, abstract OA1303]

Individuals with severe* infection within 6 months pre-assessment, regardless of whether it was COVID-19, experienced a reduction in FVC compared with those with non-severe and asymptomatic infection (p=0.045).

“Although children and adolescents tend to suffer less severe symptoms from COVID-19 infection than adults, to date there is only preliminary evidence about long-term effects of COVID-19 on pulmonary function in children and adolescents,” remarked study author Dr Anne Schlegtendal from University Children’s Hospital, Ruhr-University-Bochum, Bochum, Germany.

“It’s important to evaluate this given the fact that children worldwide will potentially get infected with SARS-CoV-2 as long as vaccines are predominantly reserved for adults and high-risk groups,” she said.

“[This study showed that] pulmonary function is rarely impaired in children and adolescents after COVID-19,” she added.

“These findings should offer some reassurance to children, adolescents, and their families. Severity of infection proved to be the only predictor for mild lung function changes and this is independent of a COVID-19 infection,” Schlegtendal continued.

However, she highlighted the discrepancy between pulmonary function and complaints. “The discrepancy between persistent breathing problems and normal lung function suggests there may be a different underlying cause, such as dysfunctional breathing, which is a problem that has also been identified in adults,” she noted.