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.