Staadegaard, LisaCaini, SaverioWangchuk, SonamThapa, BinayFerreira de Almeida, Walquiria AparecidaCotrim de Carvalho, FelipeFasce, Rodrigo ABustos, PatriciaKyncl, JanNovakova, LudmilaCaicedo, Alfredo Brunode Mora Coloma, Domenica JosethMeijer, AdamHooiveld, MariëtteHuang, Q SueWood, TimGuiomar, RaquelRodrigues, Ana PaulaLee, Vernon Jian MingAng, Li WeiCohen, CherylMoyes, JocelynLarrauri, AmparoDelgado-Sanz, ConcepcionDemont, ClarisseBangert, MathieuDückers, Michelvan Summeren, JojannekePaget, John2022-04-282022-04-282021-11Influenza Other Respi Viruses. 2021 Nov;15(6):732-741http://hdl.handle.net/20.500.12105/14222Background: Respiratory syncytial virus (RSV) infections are one of the leading causes of lower respiratory tract infections and have a major burden on society. For prevention and control to be deployed effectively, an improved understanding of the seasonality of RSV is necessary. Objectives: The main objective of this study was to contribute to a better understanding of RSV seasonality by examining the GERi multi-country surveillance dataset. Methods: RSV seasons were included in the analysis if they contained ≥100 cases. Seasonality was determined using the "average annual percentage" method. Analyses were performed at a subnational level for the United States and Brazil. Results: We included 601 425 RSV cases from 12 countries. Most temperate countries experienced RSV epidemics in the winter, with a median duration of 10-21 weeks. Not all epidemics fit this pattern in a consistent manner, with some occurring later or in an irregular manner. More variation in timing was observed in (sub)tropical countries, and we found substantial differences in seasonality at a subnational level. No association was found between the timing of the epidemic and the dominant RSV subtype. Conclusions: Our findings suggest that geographical location or climatic characteristics cannot be used as a definitive predictor for the timing of RSV epidemics and highlight the need for (sub)national data collection and analysis.engVoRhttp://creativecommons.org/licenses/by/4.0/EpidemiologyRespiratory syncytial virusSeasonalitySurveillanceAtribución 4.0 Internacional34255934156732-74110.1111/irv.128851750-2659Influenza and Other Respiratory Virusesopen access