The effects of school closures on influenza outbreaks and pandemics: systematic review of simulation studies.
BACKGROUND
School closure is a potential intervention during an influenza pandemic and has been investigated in many modelling studies.


OBJECTIVE
To systematically review the effects of school closure on influenza outbreaks as predicted by simulation studies.


METHODS
We searched Medline and Embase for relevant modelling studies published by the end of October 2012, and handsearched key journals. We summarised the predicted effects of school closure on the peak and cumulative attack rates and the duration of the epidemic. We investigated how these predictions depended on the basic reproduction number, the timing and duration of closure and the assumed effects of school closures on contact patterns.


RESULTS
School closures were usually predicted to be most effective if they caused large reductions in contact, if transmissibility was low (e.g. a basic reproduction number <2), and if attack rates were higher in children than in adults. The cumulative attack rate was expected to change less than the peak, but quantitative predictions varied (e.g. reductions in the peak were frequently 20-60% but some studies predicted >90% reductions or even increases under certain assumptions). This partly reflected differences in model assumptions, such as those regarding population contact patterns.


CONCLUSIONS
Simulation studies suggest that school closure can be a useful control measure during an influenza pandemic, particularly for reducing peak demand on health services. However, it is difficult to accurately quantify the likely benefits. Further studies of the effects of reactive school closures on contact patterns are needed to improve the accuracy of model predictions.
Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom; Statistics, Modelling and Economics Department, Public Health England, London, United Kingdom.
Charlotte
C
Jackson
Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Punam
P
Mangtani
Field Epidemiology Services, Public Health England, Birmingham, United Kingdom.
Jeremy
J
Hawker
West Midlands Public Health England Centre, Public Health England, Birmingham, United Kingdom.
Babatunde
B
Olowokure
Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom; Statistics, Modelling and Economics Department, Public Health England, London, United Kingdom.
Emilia
E
Vynnycky
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003140:Communicable Disease Control / Q000379:methods*; D003198:Computer Simulation; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission*; D008962:Models, Theoretical; D058873:Pandemics; D012574:Schools; D013997:Time Factors