Why carry out this study?

Diagnostic testing characteristics (i.e. variations in clinical specimens and diagnostic tests) can contribute to underestimation of RSV disease burden.

Existing reports on RSV disease burden did not fully account for case under-ascertainment.

We aimed to improve the understanding of RSV hospitalisation burden in older adults from high-income countries by accounting for case under-ascertainment.

What was learned from this study?

The true RSV-associated hospitalisation burden could be 2.2 times what was reported in existing studies without adjustment for case under-ascertainment.

Accounting for case under-ascertainment has implications for calculating the benefit of interventions to treat and prevent RSV disease.