Volume 19, Number 9—September 2013
Research
Protection by Face Masks against Influenza A(H1N1)pdm09 Virus on Trans-Pacific Passenger Aircraft, 2009
Table
Case–control analysis of potential risk or protective factors for 9 case-passengers infected with influenza A(H1N1)pdm09 virus and 32 control-passengers on a flight from New York, New York, to Hong Kong, China, May 2009*
Risk or protective factor | No response, no. (%)† | Response, no. (%) | OR (95% CI)‡ | 2-tailed p value‡ Case | |||
---|---|---|---|---|---|---|---|
Case |
Control |
Case |
Control |
||||
Age, y | Age, y | ||||||
<20 | 0 | 0 | 4 (44) | 4 (12) | <20 | 0 | |
20–40 | 0 | 0 | 4 (44) | 15 (47) | 20–40 | 0 | |
>40 | 0 | 0 | 1 (11) | 13 (41) | >40 | 0 | |
Male sex | 0 | 0 | 5 (56) | 15 (47) | Male sex | 0 | |
Chinese ethnicity | 0 | 0 | 8 (89) | 32 (100) | Chinese ethnicity | 0 | |
Flight from New York to Vancouver | Flight from New York to Vancouver | ||||||
Wearing mask | 0 | 0 | 1 (11) | 16 (57) | Wearing mask | 0 | |
Using lavatory 3 | 0 | 3 (11) | 2 (22) | 7 (28) | Using lavatory 3 | 0 | |
Using lavatory 5 | 1 (11) | 3 (11) | 2 (25) | 4 (16) | Using lavatory 5 | 1 (11) | |
Using lavatory 3 or 5 | 1 (11) | 1 (3.6) | 3 (38) | 11 (41) | Using lavatory 3 or 5 | 1 (11) | |
Using lavatory 3, 4, 5, or 6 | 0 | 1 (3.6) | 6 (67) | 14 (52) | Using lavatory 3, 4, 5, or 6 | 0 | |
Flight from Vancouver to Hong Kong | Flight from Vancouver to Hong Kong | ||||||
Wearing mask | 0 | 0 | 0 | 15 (47) | Wearing mask | 0 | |
Using lavatory 3 | 0 | 2 (6) | 5 (56) | 7 (23) | Using lavatory 3 | 0 | |
Using lavatory 5 | 1 (13) | 2 (6) | 1 (13) | 5 (17) | Using lavatory 5 | 1 (13) | |
Using lavatory 3 or 5 | 1 (13) | 0 | 5 (63) | 12 (38) | Using lavatory 3 or 5 | 1 (13) | |
Using lavatory 3, 4, 5, or 6 | 0 | 0 | 7 (78) | 20 (63) | Using lavatory 3, 4, 5, or 6 | 0 | |
Flight from New York to Hong Kong | Flight from New York to Hong Kong | ||||||
Wearing mask | 0 | 0 | 0 | 15 (47) | Wearing mask | 0 | |
Talking with other passengers | 0 | 0 | 2 (22) | 6 (19) | Talking with other passengers | 0 | |
Moving around airplane | 0 | 0 | 1 (11) | 3 (9.4) | Moving around airplane | 0 | |
Contact with patients with ILI | 0 | 0 | 0 | 0 | Contact with patients with ILI | 0 | |
Hand sanitation¶ | Hand sanitation¶ | ||||||
Washing hands when using lavatory | 0 | 0 | 9 (100) | 32 (100) | Washing hands when using lavatory | 0 | |
Cleaning hands before eating | 0 | 0 | 8 (89) | 29 (91) | Cleaning hands before eating | 0 | |
Among 9 case- and 17 control-passengers who did not wear masks during flight from Vancouver to Hong Kong | |||||||
Using lavatory 3 | 0 | 1 (6) | 5 (56) | 6 (38) | Using lavatory 3 | 0 | |
Using lavatory 3 or 5 | 1 (13) | 0 | 5 (63) | 9 (53) | Using lavatory 3 or 5 | 1 (13) | |
Using lavatory 3, 4, 5, or 6 | 0 | 0 | 7 (78) | 13 (76) | Using lavatory 3, 4, 5, or 6 | 0 |
*Of the 32 control-passengers on the flight from New York to Hong Kong, 28 boarded in New York and 4 boarded in Vancouver, British Columbia, Canada. OR, odds ratio; NA, not applicable; ILI, influenza-like illness; NE, not estimated.
†No. case-passengers or control-passengers who did not answer the question.
‡By Fisher Exact test and StatXact 8 (15).
§Difference among 3 age groups.
¶Always washed hands when using lavatory and always used wet towel before eating.
References
- Centers for Disease Control and Prevention. Swine influenza A (H1N1) infection in two children—Southern California, March–April 2009. MMWR Morb Mortal Wkly Rep. 2009;58:400–2 .PubMed
- World Health organization. Pandemic (H1N1) 2009 update 58 [cited 2012 Mar 14]. http://www.who.int/csr/don/2009_07_06/en/index.html
- General Administration of Quality Supervision, Inspection, and Quarantine of the People’s Republic of China. Notice on completion of entry-exit health card at land and water borders, 2009 [cited 2012 May 10]. http://www.aqsiq.gov.cn/zjxw/zjxw/zjftpxw/200905/t20090504_113171.htm
- General Administration of Quality, Supervision, and Quarantine of the People’s Republic of China. Emergency notice on prevention against the importation of human infection with swine influenza, 2009 [cited 2012 May 10]. http://www.aqsiq.gov.cn/zwgk/tzgg/200904/t20090425_112329.htm
- World Health Organization. CDC protocol of realtime RT-PCR for influenza A (H1N1) [cited 2012 Mar 14]. http://www.who.int/csr/resources/publications/swineflu/realtimeptpcr/en/
- Chinese Ministry of Health. Technical guidelines for the prevention and control of pH1N1 [in Chinese]. Beijing: Chinese Ministry of Health; 2009.
- Transmission dynamics and impact of pandemic influenza A (H1N1) 2009 virus. Wkly Epidemiol Rec. 2009;84:481–4 .PubMed
- Odaira F, Takahashi H, Toyokawa T, Tsuchihashi Y, Kodama T, Yahata Y, Assessment of secondary attack rate and effectiveness of antiviral prophylaxis among household contacts in an influenza A(H1N1)v outbreak in Kobe, Japan, May–June 2009. Euro Surveill. 2009;14:19320 .PubMed
- Fontaine RE, Goodman RA. Describing the findings: descriptive epidemiology. In: Gregg MB, editor. Field epidemiology, 3rd ed. New York: Oxford University Press; 2008. p. 156–98.
- Centre for Health Protection. Hong Kong. CHP molecular diagnostic protocols for the detection of human swine influenza type A (subtype H1) revision 2, 2009 [cited 2011 Jun 26]. http://www.chp.gov.hk/files/pdf/chp_protocols_for_the_detection_of_human_swine_influenza.pdf
- Centers for Disease Control and Prevention. H1N1 flu: interim guidance on specimen collection, processing, and testing for patients with suspected novel influenza A (H1N1) (swine flu) virus infection [cited 2012 Jun 12]. http://www.cdc.gov/h1n1flu/specimencollection.htm
- Mehta C, Patel N. StatXact 8: Software for exact nonparametric inference. Cambridge (MA): Cytel Software Corporation; 2007.
- Moser MR, Bender TR, Margolis HS, Noble GR, Kendal AP, Ritter DG. An outbreak of influenza aboard a commercial airliner. Am J Epidemiol. 1979;110:1–6 .PubMed
- Yang P, Seale H, MacIntyre CR, Zhang H, Zhang Z, Zhang Y, Mask-wearing and respiratory infection in healthcare workers in Beijing, China. Braz J Infect Dis. 2011;15:102–8 .PubMed
- Centers for Disease Control and Prevention. Seasonal influenza (flu): flu activity and surveillance [cited 2012 May 16]. http://www.cdc.gov/flu/weekly/fluactivitysurv.htm
- Bell DM; World Health Organization Writing Group. Non-pharmaceutical interventions for pandemic influenza, national and community measures. Emerg Infect Dis. 2006;12:88–94 .PubMed
- Gupta JK, Lin C-H, Chen Q. Risk assessment of airborne infectious diseases in aircraft cabins: indoor air, February 7, 2012 [cited 2012 May 13]. http://www.ncbi.nlm.nih.gov/pubmed/22313168
1These authors contributed equally to this article.
Page created: August 20, 2013
Page updated: August 20, 2013
Page reviewed: August 20, 2013
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.