Introduction:
The pandemic coronavirus disease 2019 (COVID-19) has affected millions
worldwide since March 2020. Among pediatric patients infected with the
virus, only 15% remain asymptomatic, while 90% experience mild
symptoms1. However, some symptoms persist after the
infection, known as post COVID and long COVID2, and
can significantly impact the patient’s quality of life. The common
symptoms include fatigue, insomnia, and difficulty
breathing3,4. Also, COVID-19 infection can result in
pulmonary function impairment. In adults, a restrictive ventilatory
defect was found in 64% of the patients after three months of
recuperation from COVID-19 infection as a result of post-infection
pulmonary fibrosis5.
In children, there is limited evidence on the long-term respiratory
problems of COVID-19, including abnormal pulmonary function. Previous
studies demonstrated various results that one study in children reported
no abnormal spirometry6, while another study in
adolescents identified abnormal spirometry in 24% of cases and
obstructive impairment was the most common7. In
addition, treatment guidelines for COVID-19 infection in developing
countries are usually modified due to limitations in healthcare
resources. For instance, in Thailand, many patients could not access to
the service and patients with COVID-19 pneumonia were primarily treated
with favipiravir. Variations in the management possibly lead to
different respiratory outcomes after the infection, but the outcomes in
such situations have been rarely examined.
Given that more specific data for developing countries are necessary,
this study was undertaken to investigate prevalence of respiratory
sequelae after COVID-19 infection, including residual respiratory
symptoms and pulmonary function, in Thai pediatric patients. The
secondary objective is to identify 1) the relationship between post
COVID-19 symptoms and pulmonary function impairment, 2) factors
associated with any respiratory sequelae and 3) factors associated with
quantitative changes in spirometry parameters. The novel findings from
this study may aid in comprehending the long-term effects of COVID-19
infection in Thai children and in monitoring patients at risk.