Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and lower respiratory tract infection (LRTI) among young children. It is highly contagious with transmission mainly by respiratory droplets. The RSV season usually precedes the influenza season with the average onset at the end of February (range early February – mid-March) over the past 10 years (excluding 2020 and 2021).
RSV season update
The RSV season started in week 6 of 2023 (week starting 6 February 2023) (Figure 1). Among children aged <5 years, the RSV detection rate is currently at moderate levels and continues to rise steeply. Weekly reports documenting RSV circulation are available on: https://www.nicd.ac.za/diseases-a-z-index/disease-index-covid-19/surveillance-reports/weekly-respiratory-pathogens-surveillance-report-week/.
Compared to mean circulation of RSV between 2014 and 2019, the detection rate of RSV appears to be rising more sharply in recent weeks, although within the range of what has been seen in the past (Figure 2).