title: Risk of influenza A (H5N1) infection among health care workers exposed to patients with influenza A (H5N1), Hong Kong.
abstract: The first outbreak of avian influenza A (H5N1) occurred among humans in Hong Kong in 1997. To estimate the risk of person-to-person transmission, a retrospective cohort study was conducted to compare the prevalence of H5N1 antibody among health care workers (HCWs) exposed to H5N1 case-patients with the prevalence among nonexposed HCWs. Information on H5N1 case-patient and poultry exposures and blood samples for H5N1-specific antibody testing were collected. Eight (3.7%) of 217 exposed and 2 (0.7%) of 309 nonexposed HCWs were H5N1 seropositive (P=.01). The difference remained significant after controlling for poultry exposure (P=.01). This study presents the first epidemiologic evidence that H5N1 viruses were transmitted from patients to HCWs. Human-to-human transmission of avian influenza may increase the chances for the emergence of a novel influenza virus with pandemic potential.
authors.affiliation: Centers for Disease Control and Prevention, Influenza Branch, MS A-32, 1600 Clifton Rd., Atlanta, GA 30333, USA. ctb1@cdc.gov
authors.forename: C
authors.initials: C
authors.lastname: Buxton Bridges
authors.forename: J M
authors.initials: JM
authors.lastname: Katz
authors.forename: W H
authors.initials: WH
authors.lastname: Seto
authors.forename: P K
authors.initials: PK
authors.lastname: Chan
authors.forename: D
authors.initials: D
authors.lastname: Tsang
authors.forename: W
authors.initials: W
authors.lastname: Ho
authors.forename: K H
authors.initials: KH
authors.lastname: Mak
authors.forename: W
authors.initials: W
authors.lastname: Lim
authors.forename: J S
authors.initials: JS
authors.lastname: Tam
authors.forename: M
authors.initials: M
authors.lastname: Clarke
authors.forename: S G
authors.initials: SG
authors.lastname: Williams
authors.forename: A W
authors.initials: AW
authors.lastname: Mounts
authors.forename: J S
authors.initials: JS
authors.lastname: Bresee
authors.forename: L A
authors.initials: LA
authors.lastname: Conn
authors.forename: T
authors.initials: T
authors.lastname: Rowe
authors.forename: J
authors.initials: J
authors.lastname: Hu-Primmer
authors.forename: R A
authors.initials: RA
authors.lastname: Abernathy
authors.forename: X
authors.initials: X
authors.lastname: Lu
authors.forename: N J
authors.initials: NJ
authors.lastname: Cox
authors.forename: K
authors.initials: K
authors.lastname: Fukuda
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D002353:Carrier State; D015331:Cohort Studies; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D017758:Infectious Disease Transmission, Patient-to-Professional; D053124:Influenza A Virus, H5N1 Subtype; D009980:Influenza A virus / Q000145:classification / Q000276:immunology*; D007251:Influenza, Human / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral