tailieunhanh - Báo cáo y học: "Theoretical basis to measure the impact of shortlasting control of an infectious disease on the epidemic peak"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Theoretical basis to measure the impact of shortlasting control of an infectious disease on the epidemic peak. | Omori and Nishiura Theoretical Biology and Medical Modelling 2011 8 2 http content 8 1 2 THEORETICAL BIOLOGY AND MEDICAL MODELLING RESEARCH Open Access Theoretical basis to measure the impact of shortlasting control of an infectious disease on the epidemic peak Ryosuke Omori1 5 Hiroshi Nishiura2 3 4 Correspondence nishiura@ 2PRESTO Japan Science and Technology Agency 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan 2 BioMed Central Abstract Background While many pandemic preparedness plans have promoted disease control effort to lower and delay an epidemic peak analytical methods for determining the required control effort and making statistical inferences have yet to be sought. As a first step to address this issue we present a theoretical basis on which to assess the impact of an early intervention on the epidemic peak employing a simple epidemic model. Methods We focus on estimating the impact of an early control effort . unsuccessful containment assuming that the transmission rate abruptly increases when control is discontinued. We provide analytical expressions for magnitude and time of the epidemic peak employing approximate logistic and logarithmic-form solutions for the latter. Empirical influenza data H1N1-2009 in Japan are analyzed to estimate the effect of the summer holiday period in lowering and delaying the peak in 2009. Results Our model estimates that the epidemic peak of the 2009 pandemic was delayed for 21 days due to summer holiday. Decline in peak appears to be a nonlinear function of control-associated reduction in the reproduction number. Peak delay is shown to critically depend on the fraction of initially immune individuals. Conclusions The proposed modeling approaches offer methodological avenues to assess empirical data and to objectively estimate required control effort to lower and delay an epidemic peak. Analytical findings support a critical need to conduct population-wide serological survey as a prior requirement