During the 2009 A/H1N1 influenza pandemic, very strict interventions including Fengxiao were taken in mainland China to prevent imported cases and to slow down the spread to the community. How effective the local control measures are remains to be assessed, and answers to this question may inform decisions whether there should be enforced and/or improved local control measures to mitigate the outbreak. We estimated the mean reproduction number and analyzed the effect of varying interventions on outbreak and attack rate by simulating the spatially stratified compartmental model. We found that early implementation of Fengxiao, although hardly avoid a global outbreak, did and can substantially delay the outbreak peak time. Such a measure, when coupled with other strong quarantine and hygiene precaution measures, can reduce significantly the final size and outbreak peak altogether. This finding strongly suggests that prompt interventions including Fengxiao should be implemented to respond to future waves and emerging epidemics in China.

Joint work with S. Tang, Y. Yang, Y. Zhou, J. Wu and Zima