Giuseppe
Emeritus
[Source: World Health Organization, full page: (LINK). Edited.]
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Peer-reviewed literature - 20 July 2012: Household transmission of 2009 Pandemic Influenza A(H1N1) A systematic review and meta-analysis.
Lau et al. conducted a systematic review and meta-analysis to assess and summarize the findings of household transmission studies during the 2009 H1N1 influenza pandemic and to review the design and implementation of these studies [1].Transmission of the A(H1N1)pdm virus in households during the 2009 pandemic appeared to vary among countries and settings.
Within households, the frequency of transmission from confirmed cases to their close contacts varied greatly with point estimates of the risk of secondary infection ranging from 3-38% [1]. Lau et al assert that this variation of results illustrates the heterogeneity in household study?s design and implementation.
The main recommendations from this review are to have advanced protocol preparation in place for cases like a pandemic, to use laboratory outcome measures instead of symptom based diagnostics and to include serology in household studies including acute and convalescent sera.
Comment:
Households provide a strategic setting to track influenza virus infection among close contacts of influenza cases [2,3]. When implemented, household studies give insight into novel viruses; the full range of illness associated with the virus; and the transmission characteristics of the virus in a confined setting [4], which could influence pandemic response and real-time policy interventions.
As Lau et al recommend, household studies prepared prior to pandemic outbreak may enable swift implementation during a pandemic, providing valuable information at early stages of a pandemic. However the heterogeneous nature of household study designs and implementation may impede the comparability of studies. A standardized protocol for household studies could assist in reducing this potential impediment.
Advanced planning for outbreak studies would enable a rapid and coordinated response to a pandemic and with the inclusion of sustained serological studies, estimates of transmission and severity of a novel infection could be enhanced [5].
Every study included in the review by Lau et al reported clinical influenza among household contacts [1]. This illustrates the importance of household infection control methods and supports the need for household hygiene interventions. Correct hand washing remains the gold standard for infection control as Talaat et al illustrated when showing a 50% reduction in laboratory confirmed influenza cases due to a hand washing and education intervention [6].
There is also evidence that suggests mask use initiated at early stages of contact with an infected individual may provide some protection from influenza infection, but it is best undertaken in conjunction with correct hand hygiene [7].
Personal hygiene remains the primary source of influenza transmission prevention, within households.
Reference:
(1) Lau LLH, Nishiura, H, Kelly H, Ip DKM, Leung, G & Cowling, BJ. Household transmission of 2009 Pandemic Influenza A(H1N1): A systematic review and meta-analysis. Epidemiology. 2012 July;23(4).
(2) Chao DL, Halloran ME, Obenchain VJ, Longini IM Jr. Flute, a publicly available stochastic influenza epidemic simulation model. PLoS Computational Biology. 2010;6:e1000656.
(3) Ferguson NM, Cummings DA, Fraser C, Cajka JC, Cooley PC, Burke DS. Strategies for mitigating an influenza pandemic. Nature. 2006;442:448-452.
(4) Monto AS. Studies of the community and family: acute respiratory illness and infection. Epidemiologic Reviews. 1994;16:351-373.
(5) Laurie KL, Huston P, Riley S, Katz J, Willison DJ, Tam JS et al. Influenza serological studies to inform public health action: best practices to optimize timing, quality and reporting. Influenza and Other Respiratory Viruses. 2012 April. DOI: 10.1111/j.1750-2659.2012.0370a.x
(6) Talaat M, Afifi S, Dueger E, El-Ashry N, Marfin A, Kandeel A et al. Effects of hand hygiene campaigns on incidence of laboratory-confirmed influenza absenteeism in schoolchildren, Cairo, Egypt. Emerging Infectious Diseases. 2011 April; 17(4):619-625.
(7) Use of Facemasks and Respirators in an Influenza Pandemic: Scientific Evidence Base Review. Pandemic Influenza Preparedness Team, Department of Health. 2011-22 March 2011. (http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_125425.pdf )
-Lau et al. conducted a systematic review and meta-analysis to assess and summarize the findings of household transmission studies during the 2009 H1N1 influenza pandemic and to review the design and implementation of these studies [1].Transmission of the A(H1N1)pdm virus in households during the 2009 pandemic appeared to vary among countries and settings.
Within households, the frequency of transmission from confirmed cases to their close contacts varied greatly with point estimates of the risk of secondary infection ranging from 3-38% [1]. Lau et al assert that this variation of results illustrates the heterogeneity in household study?s design and implementation.
The main recommendations from this review are to have advanced protocol preparation in place for cases like a pandemic, to use laboratory outcome measures instead of symptom based diagnostics and to include serology in household studies including acute and convalescent sera.
Comment:
Households provide a strategic setting to track influenza virus infection among close contacts of influenza cases [2,3]. When implemented, household studies give insight into novel viruses; the full range of illness associated with the virus; and the transmission characteristics of the virus in a confined setting [4], which could influence pandemic response and real-time policy interventions.
As Lau et al recommend, household studies prepared prior to pandemic outbreak may enable swift implementation during a pandemic, providing valuable information at early stages of a pandemic. However the heterogeneous nature of household study designs and implementation may impede the comparability of studies. A standardized protocol for household studies could assist in reducing this potential impediment.
Advanced planning for outbreak studies would enable a rapid and coordinated response to a pandemic and with the inclusion of sustained serological studies, estimates of transmission and severity of a novel infection could be enhanced [5].
Every study included in the review by Lau et al reported clinical influenza among household contacts [1]. This illustrates the importance of household infection control methods and supports the need for household hygiene interventions. Correct hand washing remains the gold standard for infection control as Talaat et al illustrated when showing a 50% reduction in laboratory confirmed influenza cases due to a hand washing and education intervention [6].
There is also evidence that suggests mask use initiated at early stages of contact with an infected individual may provide some protection from influenza infection, but it is best undertaken in conjunction with correct hand hygiene [7].
Personal hygiene remains the primary source of influenza transmission prevention, within households.
Reference:
(1) Lau LLH, Nishiura, H, Kelly H, Ip DKM, Leung, G & Cowling, BJ. Household transmission of 2009 Pandemic Influenza A(H1N1): A systematic review and meta-analysis. Epidemiology. 2012 July;23(4).
(2) Chao DL, Halloran ME, Obenchain VJ, Longini IM Jr. Flute, a publicly available stochastic influenza epidemic simulation model. PLoS Computational Biology. 2010;6:e1000656.
(3) Ferguson NM, Cummings DA, Fraser C, Cajka JC, Cooley PC, Burke DS. Strategies for mitigating an influenza pandemic. Nature. 2006;442:448-452.
(4) Monto AS. Studies of the community and family: acute respiratory illness and infection. Epidemiologic Reviews. 1994;16:351-373.
(5) Laurie KL, Huston P, Riley S, Katz J, Willison DJ, Tam JS et al. Influenza serological studies to inform public health action: best practices to optimize timing, quality and reporting. Influenza and Other Respiratory Viruses. 2012 April. DOI: 10.1111/j.1750-2659.2012.0370a.x
(6) Talaat M, Afifi S, Dueger E, El-Ashry N, Marfin A, Kandeel A et al. Effects of hand hygiene campaigns on incidence of laboratory-confirmed influenza absenteeism in schoolchildren, Cairo, Egypt. Emerging Infectious Diseases. 2011 April; 17(4):619-625.
(7) Use of Facemasks and Respirators in an Influenza Pandemic: Scientific Evidence Base Review. Pandemic Influenza Preparedness Team, Department of Health. 2011-22 March 2011. (http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_125425.pdf )
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