Estimated Incidence of Hospitalisations and Deaths Attributable to Respiratory Syncytial Virus Infections in Adults in Norway between 2010 and 2019: A Time-Series Modelling Study.

Background: Respiratory syncytial virus (RSV) can lead to serious respiratory illnesses in both children and adults, particularly affecting older individuals and those with chronic health issues. Due to its symptoms resembling other respiratory viruses and irregular RSV standard-of-care testing, RSV cases in adults frequently remain unreported.

Methods: We retrospectively estimated the incidence of hospitalisations and deaths attributable to RSV in adults in Norway using a time-series model-based approach. Data were obtained from the Norwegian Patient Registry and Norwegian Cause of Death Registry to estimate RSV-attributable hospitalisations and deaths, respectively, among adults from 2010 to 2019. A quasi-Poisson time-series regression model was applied to estimate RSV annual (age- and risk-stratifications) hospitalisation incidence rates (IRs) and mortality rates (per 100,000 person-years).

Results: Annual RSV-attributable hospitalisation IRs for adults aged ≥ 65 years with risk factors were 289-517 for cardiorespiratory, 243-434 for cardiovascular, and 178-318 per 100,000 person-years for respiratory hospitalisations. RSV-attributable hospitalisations represented 1-3% of total cardiorespiratory hospitalisations. Adults aged 18-44 years with risk factors had similar rates as those aged ≥ 65 years without risk factors. RSV-attributable mortality rates for adults aged ≥ 65 years were 19-35 for cardiorespiratory, 11-19 for respiratory, and 10-18 per 100,000 person-years for cardiovascular deaths. RSV-attributable deaths accounted for 1-5% of total cardiorespiratory deaths.

Conclusions: RSV significantly contributes to hospitalisations and deaths in adults in Norway, particularly among older adults and younger adults with underlying diseases. The introduction of RSV vaccines can have a substantial public health impact in reducing the burden of RSV-attributable cardiovascular and respiratory events.