School holidays and respiratory syncytial virus transmission in Sweden: An interrupted time series analysis

• DOI: 10.1111/apa.17313
• Publication Date: 2024-06-07T12:07:43Z
• Authors: Giulia Dallagiacoma; Márta K. Radó; Anna Odone; Tobias Alfvén; Samuel A. Rhedin
• Keywords: Sweden; Male; 0301 basic medicine; Schools; 330; Adolescent; Incidence; Infant, Newborn; Infant; Interrupted Time Series Analysis; Respiratory Syncytial Virus Infections; 03 medical and health sciences; Child, Preschool; 616; Humans; Female; Seasons; Child; Holidays

AbstractAimRespiratory syncytial virus (RSV) represents a significant cause of morbidity for children worldwide, especially for newborns. As RSV vaccines are not routinely used for children yet, non‐pharmaceutical interventions (NPIs) represent the main strategy for prevention. The objective of this study was to investigate the correlation between school holidays and RSV transmission.MethodsData were collected from the weekly reports on RSV incidence for the 2021/2022 and 2022/2023 seasons in Sweden. The 7‐day cumulative incidence of RSV was compared before and after the designated school holidays (Fall, Christmas, and Winter holidays).ResultsOur findings reveal an immediate (−1.7%, p < 0.001, 95% CI [−3.1%, −0.4%]) and gradual (−1.4%/week, p < 0.001, 95%CI [−1.8, −1.0]) reduction in RSV incidence following the Fall holiday in 2021, especially among children under 1 year of age, both immediately (−107.6%, p < 0.05, 95% CI [−203.7, −11.5]) and gradually afterwards (−58.5%/week, p < 0.001, 95% CI [−72.7, −44.3]). Mixed results were obtained for the Fall in 2022/2023 and for the Winter and holidays in both the studied years.ConclusionsWhile the Fall holiday in 2021/2022 was associated with a decrease in RSV incidence in Sweden, our results do not support a universal effect of school holidays on reducing RSV transmission.