Table 1. Summary of results for systematic review of literature on nonpharmaceutical interventions for pandemic influenza*.

Type of NPI	No. studies identified	Study designs included	Main findings
Isolation	15	Observational, simulation	Isolation has moderate impact in reducing influenza transmission and impact.
Quarantine	16	Intervention study, observational, simulation	Quarantine has general moderate impact in reducing influenza transmission and impact.
Contact tracing	4	Simulation	Combination of contact tracing with other measures (e.g., isolation and quarantine) can reduce influenza transmission and impact; the addition of contact tracing to existing measures might provide only modest benefit but will need substantial resources.
School closure
Planned holiday	28	Observational	The transmission of influenza decreases during routine school holidays but might increase after schools reopen.
Reactive closures	16	Observational	The effectiveness of reactive school closure varies.
Preemptive closures	13	Observational	Preemptive school closure has moderate impact in reducing influenza transmission.
Workplace measures	18	Intervention study, observational, simulation	Workplace measures are effective; combination with other interventions will further strengthen the effect.
Workplace closures	10	Simulation	Workplace closures might have modest impact in reducing influenza transmission.
Avoiding crowding	3	Observational	Timely and sustained application of measures to avoid crowding might reduce influenza transmission.
*Details of literature review are described in the Appendix.