A Systematic Review and Meta-Analysis of the Seroprevalence of Influenza A(H9N2) Infection Among Humans.

Journal Article (Journal Article;Review;Systematic Review)

INTRODUCTION: Given that influenza A(H9N2) is recognized as a pandemic threat, we evaluated the overall burden of influenza A(H9N2) infections among avian-exposed human populations. METHODS: We performed a systematic search of PubMed, AGRICOLA, and CAB Abstracts databases for literature published during 1997-2013. Studies reporting serological evidence of human influenza A(H9N2) infection among avian-exposed populations were included. We used a World Health Organization (WHO)-recommended case definition for serological evidence of infection based on results of hemagglutination inhibition (HI) and microneutralization (MN) assays. We calculated overall seroprevalence through a random effects meta-analysis model. RESULTS: Seroprevalence data reported by the studies ranged from 1% to 43% (median, 9%) by HI, which was not significantly different from the seroprevalence estimated through the WHO-recommended case definition (median, 1.3%; range, 0.5%-42.6%). Reported seroprevalence by MN ranged from 0.6% to 9% (median, 2.7%), which was greater than the seroprevalence estimated through the WHO-recommended case definition (median, 0.3%; range, 0.1%-1.4%). CONCLUSIONS: A small proportion of avian-exposed humans had evidence of influenza A(H9N2) infection. As the virus has a near global distribution in poultry, it seems likely that present surveillance efforts are missing mild or asymptomatic infections among avian-exposed persons. It seems prudent to closely monitor avian-exposed populations for influenza A(H9N2) infection to provide prepandemic warnings.

Full Text

Duke Authors

Cited Authors

  • Khan, SU; Anderson, BD; Heil, GL; Liang, S; Gray, GC

Published Date

  • August 15, 2015

Published In

Volume / Issue

  • 212 / 4

Start / End Page

  • 562 - 569

PubMed ID

  • 25712969

Pubmed Central ID

  • PMC4598807

Electronic International Standard Serial Number (EISSN)

  • 1537-6613

Digital Object Identifier (DOI)

  • 10.1093/infdis/jiv109


  • eng

Conference Location

  • United States