Incidence of RSV-related hospitalizations for ARIs, including CAP: Data from the German prospective ThEpiCAP study.

Background: RSV is a leading cause of ARI, including CAP, in older adults. Data available often underestimate RSV-related ARI incidence. We estimated RSV-related ARI hospitalization incidence from a prospective CAP study, adjusting for undiagnosed RSV infections due to nasopharyngeal/nasal swab testing only.

Methods: Active surveillance of adult CAP hospitalizations in Germany was conducted between 2021-2023. Nasopharyngeal/nasal swabs were RSV-tested, and age-group specific proportions were applied to calculate RSV-related CAP incidence. This was divided by the CAP proportions among RSV-related ARI hospitalizations (from multispecimen study) to extrapolate RSV-related ARI rates.

Results: Among 1040 radiologically confirmed CAP cases, 3.7% tested RSV-positive via nasopharyngeal/nasal swab, corresponding to 7.8% after adjusting for underdetection. For 18-59 and ≥60 years, adjusted RSV-related CAP hospitalization rates (95% CI) were 4.9 (1.8-10.9) and 115.6 (78.8-163.6); adjusted RSV-related ARI hospitalization rates were 19.8 (6.8-50.1) and 401.6 (260.7-609.3) per 100,000, respectively. Within 30 days of an RSV-related CAP admission, 18.2% of those ≥65 years died, and 11.1% and 36.4% had cardiovascular events among those 18-64 and ≥65 years, respectively.

Conclusions: Older adults in Germany experience a high burden of RSV-related ARI hospitalizations, including CAP, underscoring RSV vaccination's potential utility for this population.