Developing guidelines for school closure interventions to be used during a future influenza pandemic

Abstract

BackgroundThe A/H1N1 2009 influenza pandemic revealed that operational issues of school closure interventions, such as when school closure should be initiated (activation trigger), how long schools should be closed (duration) and what type of school closure should be adopted, varied greatly between and within countries. Computer simulation can be used to examine school closure intervention strategies in order to inform public health authorities as they refine school closure guidelines in light of experience with the A/H1N1 2009 pandemic.MethodsAn individual-based simulation model was used to investigate the effectiveness of school closure interventions for influenza pandemics with R0 of 1.5, 2.0 and 2.5. The effectiveness of individual school closure and simultaneous school closure were analyzed for 2, 4 and 8 weeks closure duration, with a daily diagnosed case based intervention activation trigger scheme. The effectiveness of combining antiviral drug treatment and household prophyaxis with school closure was also investigated.ResultsIllness attack rate was reduced from 33% to 19% (14% reduction in overall attack rate) by 8 weeks school closure activating at 30 daily diagnosed cases in the community for an influenza pandemic with R0 = 1.5; when combined with antivirals a 19% (from 33% to 14%) reduction in attack rate was obtained. For R0 >= 2.0, school closure would be less effective. An 8 weeks school closure strategy gives 9% (from 50% to 41%) and 4% (from 59% to 55%) reduction in attack rate for R0 = 2.0 and 2.5 respectively; however, school closure plus antivirals would give a significant reduction (~15%) in over all attack rate. The results also suggest that an individual school closure strategy would be more effective than simultaneous school closure.ConclusionsOur results indicate that the particular school closure strategy to be adopted depends both on the disease severity, which will determine the duration of school closure deemed acceptable, and its transmissibility. For epidemics with a low transmissibility (R0 < 2.0) and/or mild severity, individual school closures should begin once a daily community case count is exceeded. For a severe, highly transmissible epidemic (R0 >= 2.0), long duration school closure should begin as soon as possible and be combined with other interventions.

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

“…Thus, closure measures should be effective when new infections occur in the future. If herd immunity measures are employed to inhibit infectious epidemics, further interventions such as transmission interception and vaccination at not only school level but also in the wider community will be necessary [13,15].…”

“…Simulation models have shown that several weeks of school closures are necessary to reduce the cases of H1N1 [14,15], but the minimum number of closure days necessary to minimize the cases of influenza infection has not been determined. Longer closures will interfere with the education of children, with the occupations of their parents, and with social or economic activity [16,[25][26][27].…”

“…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.…”

“…Measures instituted to prevent the transmission of H1N1 included school closures [12][13][14][15]. The effects of school closures were evaluated in simulation models [14][15][16] and some reports have shown the effects of actual closures [17,18].…”

How the H1N1 influenza epidemic spread among university students in Japan: Experience from Shinshu University

“…Previous studies showed that school closure probably has a beneficial effect in reducing transmission. [7][8]13 Those studies, however, dealt mostly with the closure of whole schools rather than small units, making it unclear how the closure of small units, including high-risk groups, would affect the epidemic. In addition, we found that the second peak of infection, which included transmission via close contact with friends and lecture or laboratory work, may also be affected by closure of small units.…”