Epidemiology of Medically Attended Respiratory Syncytial Virus Lower Respiratory Tract Infection in Japanese Children, 2011–2017

Abstract

Background The objective is to report critical RSV-related epidemiological and health care resource utilization (HCRU) measures among Japanese children stratified by gestational and chronological age groups. Methods The Japanese Medical Center Database was used to retrospectively identify RSV and non-RSV infants (February 1, 2011- January 31, 2016 followed through December 31, 2017). The incidence of medically attended lower respiratory infection (MALRI) due to RSV was captured by flagging hospitalizations, outpatient visits, emergency/urgent care with an RSV diagnosis code during the RSV season. Results Of 113,529 infants and children identified, 17,022 (15%) had an RSV MALRI (14,590 during the season). The RSV MALRI and hospitalization rates in the first 5 months were 14.3/100 CY and 6.0/100 CY, respectively (13.4/100 and 5.8/100 CY for term infants and 20/100 CY and 6.8/100 CY for late preterm infants, respectively). Among those with at least one type of MALRI event during the RSV season, more than 80% of children had it by 24 months of chronological age, although this observation differed by prematurity. 60% of HCRU started in the outpatient setting. Conclusion This study emphasizes the RSV burden in young children and critically highlights the data needed to make decisions about new preventive strategies.