Transmission of pandemic influenza A (H1N1) 2009 within households: Edmonton, Canada

Sikora, Christopher; Fan, Shihe; Golonka, Richard; Sturtevant, Doris; Gratrix, Jennifer; Lee, Bonita E.; Jaipaul, Joy; Johnson, Marcia

doi:10.1016/j.jcv.2010.06.015

Cited by 38 publications

(40 citation statements)

References 11 publications

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“…Children are more likely to become infected than adults, as has been described in other studies [11], [12], [17], and this likelihood decreases with age [18]. A systematic review published by Glatman-Freedman et al analysed the SAR in children and their contacts during the pandemic influenza season, and concluded that children have a significantly higher SAR compared to adults, both in laboratory-confirmed and clinical cases, and in various settings and locations around the world [19].…”

Section: Discussionsupporting

confidence: 71%

Household Transmission of Influenza A(H1N1)pdm09 in the Pandemic and Post-Pandemic Seasons

et al. 2014

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BackgroundThe transmission of influenza viruses occurs person to person and is facilitated by contacts within enclosed environments such as households. The aim of this study was to evaluate secondary attack rates and factors associated with household transmission of laboratory-confirmed influenza A(H1N1)pdm09 in the pandemic and post-pandemic seasons.MethodsDuring the 2009–2010 and 2010–2011 influenza seasons, 76 sentinel physicians in Navarra, Spain, took nasopharyngeal and pharyngeal swabs from patients diagnosed with influenza-like illness. A trained nurse telephoned households of those patients who were laboratory-confirmed for influenza A(H1N1)pdm09 to ask about the symptoms, risk factors and vaccination status of each household member.ResultsIn the 405 households with a patient laboratory-confirmed for influenza A(H1N1)pdm09, 977 susceptible contacts were identified; 16% of them (95% CI 14–19%) presented influenza-like illness and were considered as secondary cases. The secondary attack rate was 14% in 2009–2010 and 19% in the 2010–2011 season (p = 0.049), an increase that mainly affected persons with major chronic conditions. In the multivariate logistic regression analysis, the risk of being a secondary case was higher in the 2010–2011 season than in the 2009–2010 season (adjusted odds ratio: 1.72; 95% CI 1.17–2.54), and in children under 5 years, with a decreasing risk in older contacts. Influenza vaccination was associated with lesser incidence of influenza-like illness near to statistical significance (adjusted odds ratio: 0.29; 95% CI 0.08–1.03).ConclusionThe secondary attack rate in households was higher in the second season than in the first pandemic season. Children had a greater risk of infection. Preventive measures should be maintained in the second pandemic season, especially in high-risk persons.

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Section: Discussionsupporting

confidence: 71%

Household Transmission of Influenza A(H1N1)pdm09 in the Pandemic and Post-Pandemic Seasons

et al. 2014

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“…H1N1 transmission was likely inhibited by school closures. Because H1N1 transmission risk increased among individuals who live in households with younger members [22], it was more difficult to stop the H1N1 epidemic among elementary school children than among junior high school children.…”

Section: Discussionmentioning

confidence: 99%

“…Our findings also showed that the effects of closure were related to the duration of the closure. Because an epidemic may be influenced by several factors, such as transmission within households [22,28], the severity or transmissibility of the strain of influenza [15] or weather [18], further detailed investigations that include these factors are required to clarify the effects of school closure.…”

Section: Discussionmentioning

confidence: 99%

Effect of short-term school closures on the H1N1 pandemic in Japan: a comparative case study

et al. 2012

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Purpose. The 2009 worldwide influenza A/H1N1 pandemic particularly affected younger people, including schoolchildren. We assessed the effects of class/school closure during the pandemic on the spread of H1N1 infection in Japan. Methods. We prospectively monitored 2141 schoolchildren in 57 classes at 2 elementary schools and 2 junior high schools in Japan, and we evaluated the effects of class/school closures on the spread of H1N1 using descriptive epidemiological methods.Results. The cumulative rate of H1N1 infection among these children was 40.9% (876 children). There was a total of 53 closures of 40 classes, including school closures, during the pandemic. Time-course changes in the epidemic curve showed that school closure reduced the following epidemic peak more than class closure. A Poisson regression model showed that a longer duration of closure was significantly related to decreased H1N1 occurrence after the resumption of classes. Conclusions. School closure more effectively inhibits subsequent epidemic outbreaks than class closure. Longer school closures are effective in reducing the spread of infection, and school closure should be implemented as early as possible.

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“…This result is broadly consistent with household studies showing higher susceptibility in children than in adults. 23,[82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] We are aware of only one study that has identified statistically significant age-specific differences in infectivity, 83 suggesting that this effect is less pronounced. Although our analysis indicates a higher reproduction number in children, it is important to recognize that this result is partly a consequence of age-specific mixing patterns coupled with greater susceptibility in this age group.…”

Section: Discussionmentioning

confidence: 99%

Pandemic Influenza H1N1

2012

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Transmission of pandemic influenza A (H1N1) 2009 within households: Edmonton, Canada

Cited by 38 publications

References 11 publications

Household Transmission of Influenza A(H1N1)pdm09 in the Pandemic and Post-Pandemic Seasons

Household Transmission of Influenza A(H1N1)pdm09 in the Pandemic and Post-Pandemic Seasons

Effect of short-term school closures on the H1N1 pandemic in Japan: a comparative case study

Pandemic Influenza H1N1

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