A Small Community Model for the Transmission of Infectious Diseases: Comparison of School Closure as an Intervention in Individual-Based Models of an Influenza Pandemic

Abstract

BackgroundIn the absence of other evidence, modelling has been used extensively to help policy makers plan for a potential future influenza pandemic.MethodWe have constructed an individual based model of a small community in the developed world with detail down to exact household structure obtained from census collection datasets and precise simulation of household demographics, movement within the community and individual contact patterns. We modelled the spread of pandemic influenza in this community and the effect on daily and final attack rates of four social distancing measures: school closure, increased case isolation, workplace non-attendance and community contact reduction. We compared the modelled results of final attack rates in the absence of any interventions and the effect of school closure as a single intervention with other published individual based models of pandemic influenza in the developed world.ResultsWe showed that published individual based models estimate similar final attack rates over a range of values for R0 in a pandemic where no interventions have been implemented; that multiple social distancing measures applied early and continuously can be very effective in interrupting transmission of the pandemic virus for R0 values up to 2.5; and that different conclusions reached on the simulated benefit of school closure in published models appear to result from differences in assumptions about the timing and duration of school closure and flow-on effects on other social contacts resulting from school closure.ConclusionModels of the spread and control of pandemic influenza have the potential to assist policy makers with decisions about which control strategies to adopt. However, attention needs to be given by policy makers to the assumptions underpinning both the models and the control strategies examined.

The influence of school holiday timing on epidemic impact

“…The simple SIR model allows an exploration of a range of scenarios and parameters. More complex individual-based models have been developed to predict the impact of interventions [19]; as with simple models, the results are sensitive to assumptions made about the impact of school closure on social contact patterns (see [19] for a comparison of different individual-based models). The age-structured SEIR model used here allows the incorporation of social contact data collected from the UK population during the 2009 H1N1pdm influenza epidemic.…”

“…Numerous infectious disease outbreaks take place in schools, and it is expected that schools would feature heavily in any new epidemic of influenza and similar illnesses [1,[4][5][6]. Therefore school closure has been considered as a possibility during an outbreak [7][8][9][10][11][12][13][14][15][16][17][18][19]. There are a number of reasons why school closure might take place, including staff illness, high levels of pupil absence, parental concern, or as an intervention to attempt to slow the spread of infection.…”

Simulating school closure policies for cost effective pandemic decision making

“…The possible closure triggers were a range of SAP thresholds (prevalence in children ages [5][6][7][8][9][10][11][12][13][14][15][16][17][18], based on the assumption that prevalence in this age group can be Figure 1 School closure policy pathway for high transmission scenarios. The full tree for the 0.5% school-age prevalence closure trigger is shown.…”

“…A number of studies have quantified the impact of school closures on cumulative attack rates, but have not evaluated the social and economic costs of such policies [6,[8][9][10][11][12]. Some of these studies demonstrate school closures can have a significant impact on the basic reproduction number and on the overall spread of disease [4-7, 10, 13, 14].…”

Pre-symptomatic Influenza Transmission, Surveillance, and School Closings: Implications for Novel Influenza A (H1N1)

“…Prior statistical analyses and models of school closings address several issues, including their effects on attack rates in school children and in the community ( [4], [7]), buying time for a strainspecific vaccine ( [33]), the impact of the timing and duration of school closure and flow-on effects on other social contacts ( [32]), and household responses and costs ( [25], [41]). Our model is distinguished from these in its focus on the contribution of pre-symptomatic (or early symptomatic) children to disease transmission.…”