Burden of respiratory syncytial virus infection in older and high-risk adults: a systematic review and meta-analysis of the evidence from developed countries.

Background: Respiratory syncytial virus (RSV) significantly impacts the health of older and high-risk adults (those with comorbidities). We aimed to synthesise the evidence on RSV disease burden and RSV-related healthcare utilisation in both populations.

Methods: We searched Embase and MEDLINE for papers published between 2000 and 2019 reporting the burden and clinical presentation of symptomatic RSV infection and the associated healthcare utilisation in developed countries in adults aged ≥60 years or at high risk. We calculated pooled estimates using random-effects inverse variance-weighted meta-analysis.

Results: 103 out of 3429 articles met the inclusion criteria. Among older adults, RSV caused 4.66% (95% CI 3.34-6.48%) of symptomatic respiratory infections in annual studies and 7.80% (95% CI 5.77-10.45%) in seasonal studies; RSV-related case fatality proportion (CFP) was 8.18% (95% CI 5.54-11.94%). Among high-risk adults, RSV caused 7.03% (95% CI 5.18-9.48%) of symptomatic respiratory infections in annual studies, and 7.69% (95% CI 6.23-9.46%) in seasonal studies; CFP was 9.88% (95% CI 6.66-14.43%). Data paucity impaired the calculation of estimates on population incidence, clinical presentation, severe outcomes and healthcare-related utilisation.

Conclusions: Older and high-risk adults frequently experience symptomatic RSV infection, with appreciable mortality; however, detailed data are lacking. Increased surveillance and research are needed to quantify population-based disease burden and facilitate RSV treatments and vaccine development.