title: Contagious period for pandemic (H1N1) 2009.
abstract: We estimated the proportion of persons with pandemic (H1N1) 2009 who were shedding infectious virus at diagnosis and on day 8 of illness. In households with confirmed cases, nasopharyngeal swabs were collected on all members and tested by PCR and virus culture. Of 47 cases confirmed by PCR at &lt7 days of illness, virus culture was positive in 92% (11/12) of febrile and 63% (22/35) of afebrile persons. Of 43 persons with PCR-confirmed pandemic (H1N1) 2009 from whom a second specimen was collected on day 8, 74% remained PCR positive and 19% were culture positive. If the 73 symptomatic household members without PCR-confirmed illness are assumed to have pandemic (H1N1) 2009, a minimum of 8% (6/73) of case-patients shed replicating virus on day 8. Self-isolation only until fever abates appears insufficient to limit transmission. Self-isolation for a week may be more effective, although some case-patients still would shed infectious virus.
authors.affiliation: Institut National de Sante Publique du Quebec, Quebec City, Quebec, Canada.
authors.forename: Gaston
authors.initials: G
authors.lastname: De Serres
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rouleau
authors.forename: Marie Eve
authors.initials: ME
authors.lastname: Hamelin
authors.forename: Caroline
authors.initials: C
authors.lastname: Quach
authors.forename: Danuta
authors.initials: D
authors.lastname: Skowronski
authors.forename: Louis
authors.initials: L
authors.lastname: Flamand
authors.forename: Nicole
authors.initials: N
authors.lastname: Boulianne
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Julie
authors.initials: J
authors.lastname: Carbonneau
authors.forename: Annemarie
authors.initials: A
authors.lastname: Bourgault
authors.forename: Michel
authors.initials: M
authors.lastname: Couillard
authors.forename: Hugues
authors.initials: H
authors.lastname: Charest
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004196:Disease Outbreaks; D005260:Female; D005334:Fever / Q000821:virology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000503:physiopathology / Q000635:transmission* / Q000821:virology*; D008297:Male; D009305:Nasopharynx / Q000821:virology; D010356:Patient Isolation; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D013997:Time Factors; D014776:Virus Cultivation; D017201:Virus Shedding
chemical_list: D012367:RNA, Viral
references.citation: J Infect Dis. 1979 Oct;140(4):610-3
references.pmid: 512419
references.citation: Pediatr Infect Dis J. 2005 Oct;24(10):931-2
references.pmid: 16220098
references.citation: N Engl J Med. 2009 Jun 18;360(25):2605-15
references.pmid: 19423869
references.citation: Am J Prev Med. 2010 Feb;38(2):121-6
references.pmid: 19850440
references.citation: J Clin Virol. 2009 Apr;44(4):255-61
references.pmid: 19272835
references.citation: Infect Control Hosp Epidemiol. 2007 Sep;28(9):1071-6
references.pmid: 17932829
references.citation: J Infect Dis. 2009 Aug 15;200(4):492-500
references.pmid: 19591575
references.citation: J Infect Dis. 2009 May 15;199(10):1435-41
references.pmid: 19392620
references.citation: N Engl J Med. 2009 Dec 24;361(26):2507-17
references.pmid: 20007555
references.citation: J Clin Microbiol. 2000 Nov;38(11):4096-101
references.pmid: 11060074
references.citation: J Clin Microbiol. 2009 Mar;47(3):666-73
references.pmid: 19109483
references.citation: J Infect Dis. 1981 Nov;144(5):433-41
references.pmid: 6273473
references.citation: Am J Epidemiol. 2008 Apr 1;167(7):775-85
references.pmid: 18230677
references.citation: J Clin Microbiol. 2009 Dec;47(12):3805-13
references.pmid: 19794033
references.citation: Clin Infect Dis. 2010 Apr 1;50(7):963-9
references.pmid: 20180701