Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and lower respiratory tract infection (LRTI) among young children and may cause severe illness in young infants. It is highly contagious with transmission mainly by respiratory droplets and re-infections can occur. The RSV season usually precedes the influenza season with the average onset at the end of February (range from early February to mid March) over the past 10 years (excluding 2020 and 2021).
RSV Season Update
The RSV season started in week 6 (week starting 5 February 2024) when the three-week moving average of the detection rate in children <5 years from inpatient pneumonia surveillance in public hospitals remained above 15% for two consecutive weeks. With the exception of the COVID-19 pandemic (2020) that disrupted RSV circulation, the detection rate of RSV for 2024 has risen at a similar rate to the mean circulation of RSV between 2016-2019 and 2022- 2023 at the start of the RSV season.
The RSV-B subtype has accounted for a majority of subtyped viruses in South Africa in 2024 followed by a smaller but increasing proportion of RSV-A lineage viruses (Figure 2). 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/
Alert to Clinicians
Clinicians and paediatric hospitals/ intensive care units are reminded to anticipate an increase in paediatric admissions during the RSV season. Healthcare providers are encouraged to prepare and allocate adequate resources to respond to the surge in RSV cases.
