Persistent Pulmonary Dysfunction Seen in Kids With COVID

Low-field MRI showed persistent pulmonary dysfunction in children and adolescents who either recovered from SARS-CoV-2 infection or had long COVID, a small study showed.

In a prospective clinical trial, 54 children and adolescents with previous SARS-CoV-2 infection — 29 who had recovered, and 25 with long COVID — were compared with nine healthy controls using low-field MRI.

Both ventilated and perfused lung parenchyma (V/Q match, a measure of air and blood flow to the lungs) was 81% in healthy controls, but only 62% (P=0.006) in the recovered group and 60% (P=0.003) in the long COVID group, reported Ferdinand Knieling, MD, of University Hospital Erlangen in Germany, and colleagues in Radiology.

Compared with the non-infected healthy controls, V/Q match was lower in post-COVID participants with infections within the past 180 days (63%, P=0.03), 180 to 360 days (63%, P=0.03), or beyond 360 days (41%, P<0.001).

“As children develop a robust, cross-reactive, and sustained immune response after SARS-CoV-2 infection, the observed pulmonary dysfunction in our study is an unexpected finding,” Knieling and colleagues wrote.

Capturing these images adds important information to the literature confirming children are not immune to lung dysfunction following COVID-19 infection, the researchers noted.

“In contrast to studies that are mostly based on surveys or self-reported outcomes, which suggest less severe COVID-19 infections and sequelae in younger patients, our study demonstrates widespread functional lung alterations are indeed present in children and adolescents,” they observed.

Unique to this study, the researchers used low-field MRI, a technique that has demonstrated persistent damage to lung tissue in adult patients after COVID-19. The device has a field strength of 0.55 Tesla with very quiet operating noise and lower energy absorption in tissue, allowing for a wide pediatric population to be imaged without sedation.

“We conceived this study when the evidence for long- or post-COVID cases in adults was growing,” Knieling said in a statement. “This was also when the first patients with unspecific symptoms were seen in our department and parents started to ask about an association with a prior infection.”

The prevalence of pediatric post-COVID lung disease is difficult to determine and further complicated by inconsistent, largely symptom-based definitions of long COVID and its limited applicability to children, the researchers noted.

The mean age of participants with post-acute COVID-19 was 12; mean age for controls was 10. The 25 long COVID participants met World Health Organization criteria of symptoms that lasted for at least 12 weeks. All but one patient had been vaccinated.

None of the COVID-19 group required hospital admission during the primary infection period. The median interval between positive SARS-CoV-2 RT-PCR tests and study participation was 222 days. Morphologic abnormality was identified in one recovered participant.

This study did not compare findings to other reference standards. In addition, the study used free-breathing for all intervals, which was feasible in 93% of post-acute COVID participants age 5 and older.

The study also lacked longitudinal data, and healthy control numbers were low. Families with children who have long COVID may have been more likely to participate in the study, the researchers acknowledged.

“A follow-up trial has already started, and we seek to understand how findings change over time,” Knieling said. “Additionally, we will take closer looks at other organs to see how this correlates with our findings.”