The Changing Detection Rate of Respiratory Syncytial Virus in Adults in Western Australia between 2017 and 2023

• Published in: Viruses 2024-05, Vol.16 (5), p.656
• Main Authors: Foley, David A, Minney-Smith, Cara A, Tjea, Andrew, Nicol, Mark P, Levy, Avram, Moore, Hannah C, Blyth, Christopher C
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adults; Aged; Aged, 80 and over; Climate; COVID-19 - diagnosis; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 - virology; Epidemiology; Female; Health aspects; Humans; Immunization; Incidence; Infections; Male; Middle Aged; non-pharmaceutical intervention; Public health; respiratory infection; Respiratory syncytial virus; Respiratory Syncytial Virus Infections - diagnosis; Respiratory Syncytial Virus Infections - epidemiology; Respiratory Syncytial Virus Infections - virology; Respiratory Syncytial Virus, Human - isolation & purification; respiratory virus infection; SARS-CoV-2; SARS-CoV-2 - immunology; SARS-CoV-2 - isolation & purification; Seasonal variations; Seasons; Severe acute respiratory syndrome coronavirus 2; Shelter in place; Western Australia - epidemiology; Winter; Young Adult
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v16050656

The incidence of respiratory syncytial virus (RSV) in adults is inadequately defined and the impact of SARS-CoV-2-related non-pharmaceutical interventions (NPIs) is underexplored. Using laboratory data, we described the detection rate of RSV in adults ≥16 years in Western Australia (WA) between 2017 and 2023. With the exception of 2020, RSV detections rose annually between 2017 and 2023, reaching 50.7 per 100,000 in 2023 (95% confidence interval [CI], 47.9-53.8). RSV testing expanded considerably across the study period, with the testing in 2023 more than five times the 2017 total. The detection rate was highest in adults ≥60 years between 2017 and 2019, particularly those ≥75 years. Following 2020, the detections in all age groups increased, with the highest detection rate in 2023 in those ≥75-years (199.5 per 100,000; 95% CI, 180.5-220). NPIs significantly impacted RSV seasonality; the preceding winter pattern was disrupted, resulting in an absent 2020 winter season and two major summer seasons in 2020/21 and 2021/22. The RSV season began to realign in 2022, reverting to a winter seasonal pattern in 2023 and the largest season in the study period. Ongoing surveillance will be required to understand the stability of these increases and to delineate the impact of new immunisation strategies.