A Preliminary Study Of Early Precaution Indicator System For Influenza Outbreak

BackgroundInfluenza is a highly contagious acute respiratory disease caused by influenza virus. As the highly genetic variation, wide host range and quickly spreading, influenza can cause global epidemic, which not only brought huge disasters to people’s life and health, but also have significant disruptions to economy. Influenza is a worldwide public health problem and there are no effiective measures to prevent and control its epidemic at present. The prevalence of influenza in China is one of the most notable problems, with its current large mobility population and under-developed medical care and public health system. Therefore, China was the outpost of influenza surveillance worldwide.Early detection and forecasting of infectious disease epidemic is one of the weak links for effective prevent and control of infectious disease, which is also limits the improvement of disease prevention and control ability in China. The research of forecasting methods started relatively late in China and the forecasting of influenza outbreak mostly was based on the syndromic and virological surveillance, which had obvious defects in the sensitivity and timeliness, and can’t meet the requirement of the emergency treatment of emergent public health. The epidemic of SARS and H1N1influenza make us realized that people really need to expand surveillance efforts to establish a more sensitive and effective precaution indicator system for infectious diseases forecasting. In order to detect influenza epidemic timely and improve the ability of early precaution, the research of early precaution and forecasting technique is urgently needed for national public health system.ObjectiveIn order to establish a sensitive precaution indicator system which integrated virological and epidemiological influenza surveillance and other information timely to detect the outbreak and reduce the loss caused by influenza and related diseases, systemic search of literature, semi-structured-interview and experts’consultations were used. The primary aim of this study is to explore the influenza surveillance system in China and then establish a more effective, sensitive precaution indicator system in China to detect the outbreak and reduce the high social and economic costs of influenza and then provide scientific guide for influenza prevention and control.MethodsA systematic search of literature, semi-structured-interview and experts’ consultations were used to construct the rudimental framework of the early precaution indicator system. Then an e-mail based, two-round Delphi survey was undertaken to revise and screen the precaution indicator system from a selected sample of nationally recognized experts from the field of influenza prevention and control, surveillance and management, treatment and epidemiology. Finally the weight value of each precaution indicator was determined by using expert scoring method and experts’ consulations.Results1. With the efforts for many years, great achievements have been made in the influenza surveillance and precaution system and the township and more medical institutions have been achieved the web-based influenza reporting system in China. However, there are still some problems, such as the lower comprehensive quality of medical staff, the indifference of consciousness on public health, the difficulty of communication between departments, and the inadequate of instrumentation.2. The framework of precaution indicator system of influenza was established through literature reviewing, semi-structured-interview and experts’consulting which include3categories and18secondary indexes and71indicators.3.35experts were invited to participate in two-round Delphi expert consultation.91.43%response rate in first round and96.88%response rate in second round were achieved, and33.33%and13.79%consultants put forward written suggestions for improving indicator system, which meant they were very concerned about this project. All consultants had deputy senior professional title and all of them have more than10years’professional experience in that area. The acquaintance grades to indicators were above0.7and the authority coefficients were between0.7and0.9, which proved the consultation result was credible. After two rounds’ consultations, Kendall coefficient of concordance was0.560(x2=582.786, P<0.001), which proved the opinions from experts were harmonious and the consultation was stopped. The final warning indicator system included3categories and9secondary indexes and24indicators. Detect new influenza virus type/subtype, the number of respiratory diseases in out-patient service centers and the proportion of influenza-like-illness (ILI) in sentinel hospital, the number of patient in emergency department, pediatric clinic and the proportion of ILI, the genetic or antigenic changes of circulating strains were ranked in the first5placeConclusions1. The monitoring and precaution system of influenza is not perfect in China currently, and it’s difficult to indentify influenza outbreak and epidemic through information sharing and cooperation among the different departments.2. The established precaution indicator system included3categories and24indicators, which covers the most process and scope of disease outbreak, and could be used as basic indicators for early warning.3. The indicators with relatively higher weighted coefficients were usually paid more attention and applied in practice, so the result was in accordance with the practice and the results of semi-structured interview.