title: Accuracy of epidemiological inferences based on publicly available information: retrospective comparative analysis of line lists of human cases infected with influenza A(H7N9) in China.
abstract: BACKGROUND
  Appropriate public health responses to infectious disease threats should be based on best-available evidence, which requires timely reliable data for appropriate analysis. During the early stages of epidemics, analysis of 'line lists' with detailed information on laboratory-confirmed cases can provide important insights into the epidemiology of a specific disease. The objective of the present study was to investigate the extent to which reliable epidemiologic inferences could be made from publicly-available epidemiologic data of human infection with influenza A(H7N9) virus.
  
  
  METHODS
  We collated and compared six different line lists of laboratory-confirmed human cases of influenza A(H7N9) virus infection in the 2013 outbreak in China, including the official line list constructed by the Chinese Center for Disease Control and Prevention plus five other line lists by HealthMap, Virginia Tech, Bloomberg News, the University of Hong Kong and FluTrackers, based on publicly-available information. We characterized clinical severity and transmissibility of the outbreak, using line lists available at specific dates to estimate epidemiologic parameters, to replicate real-time inferences on the hospitalization fatality risk, and the impact of live poultry market closure.
  
  
  RESULTS
  Demographic information was mostly complete (less than 10% missing for all variables) in different line lists, but there were more missing data on dates of hospitalization, discharge and health status (more than 10% missing for each variable). The estimated onset to hospitalization distributions were similar (median ranged from 4.6 to 5.6 days) for all line lists. Hospital fatality risk was consistently around 20% in the early phase of the epidemic for all line lists and approached the final estimate of 35% afterwards for the official line list only. Most of the line lists estimated >90% reduction in incidence rates after live poultry market closures in Shanghai, Nanjing and Hangzhou.
  
  
  CONCLUSIONS
  We demonstrated that analysis of publicly-available data on H7N9 permitted reliable assessment of transmissibility and geographical dispersion, while assessment of clinical severity was less straightforward. Our results highlight the potential value in constructing a minimum dataset with standardized format and definition, and regular updates of patient status. Such an approach could be particularly useful for diseases that spread across multiple countries.
authors.forename: Eric H Y
authors.initials: EH
authors.lastname: Lau
authors.forename: Jiandong
authors.initials: J
authors.lastname: Zheng
authors.forename: Tim K
authors.initials: TK
authors.lastname: Tsang
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Liao
authors.forename: Bryan
authors.initials: B
authors.lastname: Lewis
authors.forename: John S
authors.initials: JS
authors.lastname: Brownstein
authors.forename: Sharon
authors.initials: S
authors.lastname: Sanders
authors.forename: Jessica Y
authors.initials: JY
authors.lastname: Wong
authors.forename: Sumiko R
authors.initials: SR
authors.lastname: Mekaru
authors.forename: Caitlin
authors.initials: C
authors.lastname: Rivers
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.forename: Jianxing
authors.initials: J
authors.lastname: Yu
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhaorui
authors.initials: Z
authors.lastname: Chang
authors.forename: Fengfeng
authors.initials: F
authors.lastname: Liu
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Peng
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.forename: Luzhao
authors.initials: L
authors.lastname: Feng
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Special Administrative Region, China. bcowling@hku.hk.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
authors.forename: Hongjie
authors.initials: H
authors.lastname: Yu
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D058872:Epidemics; D062306:Geography, Medical; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype; D005585:Influenza in Birds / Q000453:epidemiology; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality / Q000635:transmission; D011200:Poultry; D012189:Retrospective Studies