Proportion of chickenpox consultations in different age groups, 1967–2008.

<p>Proportion of chickenpox consultations in different age groups, 1967–2008.</p

Estimated percentage difference between the contact parameter (per fortnight) for chickenpox during termtime and holidays.

<p>A) all school holidays; B) summer holidays, with different values of α. A positive value represents a reduction in the contact parameter during holidays.</p

Percentage reduction in the contact parameter for chickenpox during school holidays, by year, 1967–2008.

<p>Estimates are based on the simple mass action model. Error bars show 95% confidence intervals.</p

Fortnightly estimates of the contact parameter for chickenpox as estimated by TSIR modelling.

<p>A) 1967–76; B) 1977–97; C) 1998–2008; with values of α as shown. Error bars show 95% confidence intervals. Shaded rectangles show the approximate timing of school holidays. Fortnight 1 is the first two weeks of January; fortnight 26 is the last two weeks of December.</p

Assessment of model fit for chickenpox data, treating 1967–76, 1977–97 and 1998–2008 separately.

<p>A) Relationship between the RCGP chickenpox consultation rates and the fitted values from the regression (scaled down for under-reporting); B) RCGP data and the values predicted by the difference equations using the estimated contact parameters.</p

Plot of the predicted reduction in the cumulative attack rate against that in the peak incidence (all ages).

<p>Each marker represents the results of one analysis. Different symbols are used to reflect different values for R₀.</p

Summary of the estimated effects of school closures on cumulative incidence of pandemic influenza (all ages) predicted by the modelling studies.

<p>Different symbols are used to reflect the assumed value for R₀. The findings are grouped according to whether they assumed that the community/household contacts increased, remained unchanged, the assumptions about contact were based on empirical data or were unclear. Some studies assumed that workplaces and/or other public places also closed <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-Ferguson2" target="_blank">[11]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-CiofidegliAtti1" target="_blank">[23]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-Rizzo1" target="_blank">[28]</a>. All studies that stated their assumptions regarding the effects of school closure on contact patterns assumed that contacts between school-aged children were reduced or eliminated.</p

Influence of the duration of school closure on the predicted effects on pandemic influenza.

<p>Reductions in peak incidence (A and B) and cumulative attack rates (C and D) for different values of R₀ and assumed thresholds for school closure. Lines join predictions from the same model using the same sets of assumptions.</p

Summary of the estimated effects of school closures on peak incidence of pandemic influenza (all ages) predicted by the modelling studies.

<p>Different symbols are used to reflect the assumed value for R₀. The findings are grouped according to whether they assumed that the community/household contacts increased, remained unchanged, the assumptions about contact were based on empirical data or were unclear. Some studies assumed that workplaces and/or other public places also closed <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-Ferguson2" target="_blank">[11]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-CruzPacheco1" target="_blank">[14]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-CiofidegliAtti1" target="_blank">[23]</a>. All studies that stated their assumptions regarding the effects of school closure on contact patterns assumed that contacts between school-aged children were reduced or eliminated.</p

Summary of the key findings of factors influencing the impact of school closures, as reflected by the predicted reduction in the peak incidence and the cumulative attack rate.

<p>* Some ineligible studies suggest that very large reductions in contact may be less beneficial than smaller reductions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-Hollingsworth1" target="_blank">[60]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097297#pone.0097297-Eames2" target="_blank">[61]</a>.</p