title: Short-term treatment with zanamivir to prevent influenza: results of a placebo-controlled study.
abstract: We explored the prophylactic activity of zanamivir after presumed exposure to influenza in the community. After close contacts with index cases of influenza-like illnesses, 575 subjects were randomized in 4 treatment groups: 144 received placebo, 141 received intranasal zanamivir, 144 received inhaled zanamivir, and 146 received inhaled plus intranasal zanamivir for 5 days. Of 25 subjects (4%) who developed symptomatic influenza during the 5 days of prophylaxis, 9 (36%) were in the placebo group, 8 (32%) were in the intranasal zanamivir group (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.30-2.72; P=.855), 3 (12%) were in the inhaled zanamivir group (OR, 0.27; 95% CI, 0.07-1.05; P=.058), and 5 (20%) were in the inhaled plus intranasal zanamivir group (OR, 0.52; 95% CI, 0.17-1.58; P=.247). Short-term treatment with intranasal zanamivir was ineffective. However, inhaled zanamivir treatment reduced the rate of influenza, which was 2%-3% among zanamivir recipients versus 6% among placebo recipients. Additional studies assessing a longer duration of postcontact prophylaxis are warranted.
authors.affiliation: Division of Epidemiology and Virology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
authors.forename: L
authors.initials: L
authors.lastname: Kaiser
authors.forename: D
authors.initials: D
authors.lastname: Henry
authors.forename: N P
authors.initials: NP
authors.lastname: Flack
authors.forename: O
authors.initials: O
authors.lastname: Keene
authors.forename: F G
authors.initials: FG
authors.lastname: Hayden
mesh_terms: D000280:Administration, Inhalation; D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006146:Guanidines; D006801:Humans; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011714:Pyrans; D012794:Sialic Acids / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D016896:Treatment Outcome; D053243:Zanamivir
chemical_list: D000998:Antiviral Agents; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D053243:Zanamivir