World Health Organization Influenza-Like Illness Underestimates the Burden of Respiratory Syncytial Virus Infection in Community-Dwelling Older Adults

J Infect Dis. 2022 Aug 12;226(Suppl 1):S71-S78. doi: 10.1093/infdis/jiab452.

Abstract

Background: Respiratory syncytial virus (RSV) surveillance is heavily dependent on the influenza-like illness (ILI) case definition from the World Health Organization (WHO). Because ILI includes fever in its syndromic case definition, its ability to accurately identify acute respiratory tract infections (ARTI) caused by RSV in older adults is uncertain.

Methods: The accuracy of the WHO ILI and a modified ILI (requiring only self-reported fever) case definitions in identifying patients with PCR-confirmed RSV-ARTI was evaluated in community-dwelling older adults (≥60 years) from the prospective European RESCEU cohort study.

Results: Among 1040 participants, 750 ARTI episodes were analyzed including 36 confirmed RSV-ARTI. Due to a general lack of fever, sensitivity for RSV-ARTI was 33% for modified ILI and 11% for ILI. The area under the curve for both ILI definitions was 0.52 indicating poor discrimination for RSV. RSV-ARTI could not be distinguished from all other ARTI based on clinical symptoms.

Conclusions: The use of ILI underestimated the occurrence of RSV-ARTI in community-dwelling older adults up to 9-fold (11% sensitivity). Because worldwide RSV surveillance depends largely on ILI, there is an urgent need for a better approach to measure the occurrence of RSV disease and the impact of future RSV vaccine introduction. Clinical Trials Registration. NCT03621930.

Keywords: ILI; RESCEU; RSV; case definition; older adults; respiratory syncytial virus.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cohort Studies
  • Fever
  • Humans
  • Independent Living
  • Infant
  • Influenza, Human* / diagnosis
  • Influenza, Human* / epidemiology
  • Prospective Studies
  • Respiratory Syncytial Virus Infections* / diagnosis
  • Respiratory Syncytial Virus Infections* / epidemiology
  • Respiratory Syncytial Virus, Human*
  • Respiratory Tract Infections*
  • Virus Diseases*
  • World Health Organization

Associated data

  • ClinicalTrials.gov/NCT03621930