Background Western Australia (WA) public health measures to eradicate SARS‐CoV‐2 resulted in a secondary reduction in paediatric respiratory syncytial virus (RSV) admissions. Following an absent expected 2020 winter peak, RSV‐positive admissions surged during the summer of 2020. Aim This report examines the number of RSV‐positive admissions and severities across 36 months to better understand this out‐of‐season epidemic. Methods A retrospective observational study was performed assessing the number and severity of RSV‐related respiratory hospitalisations at a peripheral paediatric centre from March 2018 to February 2021. Data were extracted from the hospital clinical database. Results The total number of included participants was n = 294. The total number of RSV hospitalisations in SY (study year) 2018 (March 2018 to February 2019), SY 2019 (March 2019 to February 2020) and SY 2020 (March 2020 to February 2021) was 67, 98 and 129, respectively. Prior to SARS‐CoV‐2, RSV hospitalisations were highest during the winter months. In SY 2020, there were 0 RSV hospitalisations during winter, while 101 admissions in the following summer season. The proportion of admissions requiring respiratory support was significantly reduced in SY 2020 (34.1%) compared to SY 2018 (46.9%, P = 0.050) and SY 2019 (55.2%, P = 0.004). The median length of stay (LOS) in 2020 was 2.0 which was significantly reduced from 2018 and 2019 which was 3.0, P = 0.001; and 3.0, P < 0.001, respectively. Conclusion Following a period of RSV absence, there was an unprecedented surge in admission, however, with lower severity and shorter LOS.

Osteoclasts are giant bone-digesting cells that harbor specialized lysosome-related organelles termed secretory lysosomes (SLs). SLs store cathepsin K and serve as a membrane precursor to the ruffled border, the osteoclast’s ‘resorptive apparatus’. Yet, the molecular composition and spatiotemporal organization of SLs remains incompletely understood. Here, using organelle-resolution proteomics, we identify member a2 of the solute carrier 37 family (Slc37a2) as a SL sugar transporter. We demonstrate in mice that Slc37a2 localizes to the SL limiting membrane and that these organelles adopt a hitherto unnoticed but dynamic tubular network in living osteoclasts that is required for bone digestion. Accordingly, mice lacking Slc37a2 accrue high bone mass owing to uncoupled bone metabolism and disturbances in SL export of monosaccharide sugars, a prerequisite for SL delivery to the bone-lining osteoclast plasma membrane. Thus, Slc37a2 is a physiological component of the osteoclast’s unique secretory organelle and a potential therapeutic target for metabolic bone diseases.

Osteoclasts are giant bone-digesting cells that harbour specialized lysosome-related organelles termed secretory lysosomes (SLs). SLs store cathepsin K and serve as a membrane precursor to the ruffled border, the osteoclast’s ‘resorptive apparatus’. Yet, the molecular composition and spatiotemporal organization of SLs remains incompletely understood. Here, using organelle-resolution proteomics, we identify member a2 of the solute carrier 37 family (Slc37a2) as a SL sugar transporter. We demonstrate that Slc37a2 localizes to the SL limiting membrane and that these organelles adopt a hitherto unnoticed but dynamic tubular network in living osteoclasts that is required for bone digestion. Accordingly, mice lacking Slc37a2 accrue high bone mass owing to uncoupled bone metabolism and disturbances in SL export of monosaccharide sugars, a prerequisite for SL delivery to the ruffled border. Thus, Slc37a2 is a physiological component of the osteoclast’s unique secretory organelle and a potential therapeutic target for metabolic bone diseases.