title: Heterogeneous and Dynamic Prevalence of Asymptomatic Influenza Virus Infections.
abstract: Influenza infection manifests in a wide spectrum of severity, including symptomless pathogen carriers. We conducted a systematic review and meta-analysis of 55 studies to elucidate the proportional representation of these asymptomatic infected persons. We observed extensive heterogeneity among these studies. The prevalence of asymptomatic carriage (total absence of symptoms) ranged from 5.2% to 35.5% and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) from 25.4% to 61.8%. Statistical analysis showed that the heterogeneity could not be explained by the type of influenza, the laboratory tests used to detect the virus, the year of the study, or the location of the study. Projections of infection spread and strategies for disease control require that we identify the proportional representation of these insidious spreaders early on in the emergence of new influenza subtypes or strains and track how this rate evolves over time and space.
authors.forename: Luis
authors.initials: L
authors.lastname: Furuya-Kanamori
authors.forename: Mitchell
authors.initials: M
authors.lastname: Cox
authors.forename: Gabriel J
authors.initials: GJ
authors.lastname: Milinovich
authors.forename: Ricardo J Soares
authors.initials: RJ
authors.lastname: Magalhaes
authors.forename: Ian M
authors.initials: IM
authors.lastname: Mackay
authors.forename: Laith
authors.initials: L
authors.lastname: Yakob
mesh_terms: D058345:Asymptomatic Infections; D006801:Humans; D009980:Influenza A virus; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D011159:Population Surveillance; D015995:Prevalence; D017594:Publication Bias
keywords: asymptomatic; flu; influenza; meta-analysis; pandemic; prevalence; subclinical; symptomless proportion