Objectives: This study sought to determine the epidemiology, seasonal variations, morbidity, and mortality of respiratory syncytial virus (RSV) infection among hospitalized children with lower respiratory tract infection in Thailand. In addition, we assessed the risk factors associated with severe RSV lower respiratory tract infection (LRTI)-related morbidity and mortality. Methods: The data were reviewed retrospectively from the National Health Security Office for hospitalized children younger than 18 years old diagnosed with RSV-related LRTI in Thailand, between the fiscal years of 2015 to 2020. The RSV-related LRTIs were identified using the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Thai Modification. ICD-10-TM codes J12.1, J20.5, and J21.0, which represent respiratory syncytial virus pneumonia, acute bronchitis due to respiratory syncytial virus, and acute bronchiolitis due to respiratory syncytial virus, respectively, were studied. Results: During the study period, RSV-related LRTI accounted for 19,340 of the 1,610,160 hospital admissions due to LRTI. RSV pneumonia was the leading cause of hospitalization (13,684/19,340; 70.76%), followed by bronchiolitis (2849/19,340; 14.73%) and bronchitis (2807/19,340; 14.51%), respectively. The highest peak incidence of 73.55 percent occurred during Thailand’s rainy season, from August to October. The mortality rate of RSV-related LRTI in infants younger than 1 year of age was 1.75 per 100,000 person years, which was significantly higher than that of children 1 to younger than 5 years old and children 5 to younger than 18 years old (0.21 per 100,000 person years and 0.01 per 100,000 person years, respectively, p-value < 0.001). Factors associated with mortality were congenital heart disease, hematologic malignancy, malnutrition, and neurological disease. Conclusions: In children with RSV LRTI, pneumonia was the leading cause of hospitalization. The admission rate was highest during the rainy season. Mortality from RSV-related LRTI was higher in children under 1 year old and in children with underlying illnesses; future preventive interventions should target these groups of patients.

Background: The COVID-19 outbreak emerged in January 2020 and remains present in 2022. During this period, nonpharmaceutical interventions (NPIs) have been used to reduce the spread of COVID-19 infection. Nationwide data analysis should be pushed as the new standard to demonstrate the impact of COVID-19 infection on other respiratory illnesses and the reliability of NPIs during treatment. Objective: This study aims to identify and compare the incidence of lower respiratory tract infections (LRTIs) among children in Thailand before and after the emergence of COVID-19. Methods: A retrospective study was carried out in hospitalized children under the age of 18 in Thailand from October 2015 to September 2020. The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Thai Modification, was used to identify patient diagnoses (ICD-10-TM). The data were extracted from the Universal Coverage Health Security Scheme Database. Results: A total of 1,610,160 admissions were attributed to LRTIs. The most common diagnosis was pneumonia (61.9%). Compared to the 2019 fiscal year, the number of hospitalizations due to LRTIs decreased by 33.9% in the 2020 fiscal year (COVID-19 period) (282,590 vs. 186,651). The incidence of all three diagnostic groupings was substantially lower in the pre- and post-COVID-19 eras, with a decrease of 28% in the pneumonia group (incidence rate ratio (IRR) = 0.72; 95% confidence interval (CI): 0.71 to 0.72), 44% in the bronchiolitis group (IRR = 0.56; 95% CI: 0.55 to 0.57), and 34% in the bronchitis group (IRR = 0.66; 95% CI: 0.65 to 0.67). Between fiscal years 2019 and 2020, the overall monthly cost of all hospitalizations for LRTIs decreased considerably (p value < 0.001). Conclusions: NPIs may decrease the number of pediatric hospitalizations related to LRTIs. All policies designed to prevent the spread of COVID-19 must be continually utilized to maintain the prevention of LRTIs.