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Consultation on global influenza surveillance, Geneva, 10–12 July 2013 (WHO/WER, edited)

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  • Consultation on global influenza surveillance, Geneva, 10–12 July 2013 (WHO/WER, edited)

    [Source: World Health Organization, Weekly Epidemiological Record, full PDF document: (LINK). Edited.]

    Weekly epidemiological record / Relevé épidémiologique hebdomadaire, 17 january 2014, 89th year / 17 janvier 2014, 89e année, No. 3, 2014, 89, 29–36,

    Consultation on global influenza surveillance, Geneva, 10–12 July 2013


    Global surveillance of influenza is essential to monitor, detect and enable the assessment of events of potential public health significance associated with seasonal, zoonotic and pandemic influenza.

    The WHO Global Influenza Programme has been conducting influenza surveillance through the Global Influenza Surveillance and Response System (GISRS) for the past 60 years. GISRS initially focused on monitoring of circulating viruses to inform vaccine strain selection. In recent years, however, through the response to highly pathogenic avian influenza A(H5N1), pandemic A(H1N1)2009, and recently to influenza A(H7N9) and H3N2v, it has become clear that more information on the epidemiology, and better integrated analysis of epidemiological and virological information, are needed to conduct thorough evidence-based risk assessments of events to inform policy decisions.

    Progress has been made in implementing the epidemiological component of influenza surveillance globally. The WHO global influenza surveillance manual will be published shortly, a WHO manual on estimation of influenza burden has been developed, and tools to visualize influenza epidemiologic and virological data are in preparation.

    A Consultation on Global Influenza Surveillance was held in Geneva on 10–12 July, with participation from all WHO Regions (with 39 experts) as well as WHO staff.

    Objectives of the consultation

    The consultation aimed to improve global surveillance of influenza through:
    • a review of the current strategy of global influenza surveillance – for both routine seasonal influenza and influenza emergencies, and  identification of gaps and possible solutions for the short and medium term.

    Session 1: review of the current strategy for global influenza surveillance

    During the first session, the participants reviewed existing guidance for the global influenza surveillance strategy. The purpose of the session was to describe the rationale for and components of influenza surveillance and to review current guidance, manuals, and tools for influenza surveillance, assessment of disease burden and severity of influenza viruses, and pandemic preparedness.

    Following are the main points from the discussions in this session.

    Key outcomes of the session

    Objectives of influenza surveillance

    Influenza surveillance should address 2 main objectives: early detection of events with pandemic potential due to pathogens causing severe respiratory disease and monitoring of influenza activity to understand trends or patterns. To meet these objectives 2 complementary systems are required: (1) routine surveillance for respiratory illness and (2) an early warning system for unusual events. The involvement of informed and astute clinicians is critical to the success of the second system, while both surveillance systems should include epidemiology and laboratory components.

    For routine surveillance, influenza-like illness (ILI) and Severe Acute Respiratory Infection (SARI) sentinel surveillance systems provide the methods of choice for monitoring routine respiratory virus infections. Data from routine ILI and SARI systems are needed to create a baseline reference point for assessing unusual events.

    Routine surveillance systems, once established, can also serve as a basis for additional studies such as disease burden and severity assessment, and for enhancements to the system in response to an unusual event or pandemic virus spread. Further, once well established, the systems can be extended to include surveillance of other respiratory pathogens. For early warning systems of unusual events, timing is critical. Impetus for the development of an event based surveillance systems may come from the International Health Regulations (IHR), which require countries to have capacity to detect and report unusual or novel pathogens that pose an international public health threat.

    In order to understand influenza activity around the world and to contribute to decision-making concerning vaccine composition, diagnostics, antivirals and nonpharmaceutical interventions, data collected from surveillance should be shared routinely with WHO at regional and global level.

    Participants stressed that quality of data is more important than quantity for the surveillance system. This implies that high priority must be given to quality assurance for influenza surveillance as well as a standard approach to the regular evaluation of the system.

    Review of existing WHO guidance

    During the discussion session, participants were asked to share their experiences with using existing WHO guidance. WHO guidance documents on ILI and SARI surveillance, avian influenza A(H5N1) and pandemic preparedness are commonly used by countries either in the original version or modified to meet specific country needs. It was felt important to keep guidance flexible and allow for adjustment when new information becomes available. Additionally, many felt that efforts should be made to coordinate or develop a consensus between similar guidance from different agencies such as the United States Centers for Disease Control and Prevention, European Centre for Disease Control, or Health Protection England.

    Participants underlined the need for more advocacy for respiratory disease surveillance targeted to Ministries of Health, to convince them of the impact and burden of respiratory diseases on their national populations.

    There was a call for more engagement in advocacy by the different WHO offices, for example by promoting the guidance documents for monitoring and responding to influenza with Ministries of Health. Additionally, it was considered that the appropriate education of medical personnel is critical for the effectiveness of any surveillance system and should start during medical training and continue throughout medical careers, with involvement of medical associations.

    Proposals for further WHO guidance

    The following guidance documents were identified as being potentially helpful and were suggested to WHO to consider for development:
    • Advocacy assistance for surveillance aimed to encourage stakeholders to commit to influenza surveillance
    • Evaluation of surveillance systems
      • How to assess surveillance systems annually, to periodically evaluate the system fully, and to implement improvements
      • Resource utilization guidance (including how to function with limited funds)
      • Sensitivity analysis: how much information is lost or gained when surveillance sentinel sites are removed or added, and how much is gained or lost when only a proportion of the samples are tested?

    • Guidance for countries on severity assessment of seasonal epidemics as well as guidance on how the severity of a pandemic can be assessed at national and global level
    • Generic protocols for special studies
      • Examples: generic protocols for special studies such as burden estimates for pneumonia due to different respiratory pathogens; studies to identify risk factors for infection or severe outcome (e.g. special populations, travel, mass gatherings such as the Hajj, clusters of illness); populationbased surveillance; monitoring of excess mortality. Results could be placed online for easy access.

    • Guidance for enhancing or expanding surveillance in response to an outbreak, pandemic or novel virus
    • Guidance for developing pandemic preparedness plans
    • Guidance on how to integrate surveillance systems to capture multiple pathogens
    • Guidance on data management
    • Generic data management tool

    Session 2: review of implementation of influenza surveillance

    During this session, participants were asked to share their experiences in implementing influenza surveillance and to state whether and how WHO tools were used in this process. The main objectives of this session were to share examples of utilizing WHO surveillance tools either to establish a new system or to improve an existing system, to share examples of response to unusual or novel events through enhancements of systems, and to share experiences with using existing systems or data to answer additional research questions.

    Key outcomes of the discussion on how to improve or maintain a good quality surveillance system It is essential to have commitment and financial support from the Ministry of Health to establish and maintain any surveillance system. While it was seen as essential to have seed money from donors for special studies, the routine surveillance should be ensured through a sustained budget from the government. It was noted that many countries also need continuing technical support, and a variety of training programmes for both laboratory and epidemiology to enhance local capacity and commitment. Participants also noted that WHO Collaborating Centres should continue to provide assistance with shipping samples, provision of laboratory reagents and information, as well as supporting the external quality assurance programme.

    Key outcomes of the discussion on enhancements of surveillance systems

    Any system can be enhanced, but certain criteria should be met for each type of enhancement. For enhancements to address questions such as severity or disease burden, the system should be a well-functioning system that collects multiple data points consistently for a specific period of time (i.e. multiple years/seasons). For enhancements to examine new types of data collection (e.g. ICD codes), the data obtained should be evaluated and validated by comparing to traditional data sources and, whenever possible, epidemiology data should be linked to laboratory data.

    For enhancements to respond to a novel virus, outbreak or a pandemic, the existing surveillance system must be a strong or well-established system that can be easily modified to capture additional data in a timely manner and flexible enough to detect the occurrence of multiple novel pathogens.

    Finally, any enhancement to a surveillance system will require additional funds to support the work as well as guidance on how to answer specific research questions (e.g. sample protocols) or to detect novel viruses (e.g. case definitions or screening questions).

    Key points from the discussion on essential influenza surveillance components

    Three key themes emerged: (1) the importance of a laboratory component, (2) the need to maintain and ensure the quality of the system and data collected, and (3) the potential efficiency gains from integrating surveillance systems for multiple pathogens. It was evident that, if funding were not an issue, both SARI and ILI surveillance with diagnostic testing of all specimens would be maintained. However, if both could not be maintained, participants would favour maintenance of SARI surveillance and consideration of sampling strategies to reduce the number of specimens to be tested. As the laboratory is an essential and core component of any surveillance system, it was suggested that additional on-site training for laboratory staff to enhance their ability to identify unsubtypable viruses and to undertake additional tests on positive specimens would be beneficial, as well as assisting in integrating systems to include other pathogens. Additional training in techniques such as multiplex PCR testing, sequencing and subtyping, may be helpful as they consider system integration and partnerships.

    To ensure the quality of data collected and testing conducted, participants recommended the routine evaluation of surveillance systems (e.g. effectiveness of existing sites, sensitivity analysis of case definitions) with feedback to the sites on areas for improvement.

    Provision of training for clinical and epidemiology staff on all components of the system, with mechanisms in place to train new staff as well as provide periodic refresher training, was also suggested. In considering integration of systems by using one surveillance platform to identify multiple pathogens, it was suggested that building on an existing system, but allowing for broader or multiple case definitions to encompass other pathogens, would potentially distribute the costs between several groups and improve long-term sustainability.

    Some suggestions on how to integrate systems included integration of reporting systems, utilizing data that is already being collected (e.g. ICD codes), and strengthening links between animal and human surveillance systems.

    Key points on how WHO can assist in maintaining influenza surveillance

    Several ideas were put forward on how WHO can assist in ensuring that influenza surveillance is maintained:

    (i) It was suggested that WHO should develop and implement a routine accreditation mechanism for National Influenza Centrs (NICs) to reflect their value and raise their profile with their respective Ministries of Health.

    (ii) WHO could promote the integration of surveillance systems to include other pathogens for sustainability; this message from WHO could encourage donors to consider supporting the backbone of surveillance, reducing duplication through vertical funding streams.

    (iii) WHO might usefully integrate some of their systems, for example by building an epidemiology component in FluNet and by integrating data entry for FluNet and FluID to enable immediate linkage of the epidemiology and laboratory data for analysis.

    (iv) WHO could create a working group to discuss ways to maintain SARI surveillance at a lower cost as well as to review ways to integrate data generated by other systems, e.g. intensive care unit (ICU) surveillance.

    (v) assistance from WHO would be valuable in generating tools to evaluate surveillance systems, with information on what is a ‘high quality’ system.

    (vi) WHO could create and provide training courses in data analysis, data management, and dissemination (e.g. developing abstracts, presentations, manuscripts, reports, communication messages, etc.).

    Session 3: sharing and analysis of influenza surveillance information

    The objectives of this session were to describe the importance of collecting both epidemiological and laboratory data, to provide examples of how surveillance data are used to inform decisions on influenza prevention and control, and to share examples of routine reports generated by WHO headquarters, regional offices and individual countries. Presentations for this session were designed to describe the standard set of epidemiological variables that should be collected and analysed in routine surveillance systems; how to use epidemiology data in targeting public health interventions, such as vaccination; the utility and necessity of sharing surveillance data through the WHO FluNet and FluID systems; and the components of routine reports of surveillance data.

    Key points from the discussion

    Some earlier themes re-emerged, such as the need for additional training for data management and analysis. In addition, participants expressed a need for training in risk communication to identify strategies and tools to communicate with different audiences within the countries (e.g. general public, clinicians, government officials, Ministries of Health). It was also considered that the FluNet and FluID systems could include simple analysis programmes with report templates to allow countries to complete basic tables and figures with their data and to customize a routine report that could be shared with partners. With this type of enhancement of the FluNet and FluID systems, it was felt that countries would be more willing to upload their data. Finally, participants recommended that WHO create an epidemiology network to share methodologies, experiences, analysis tools and other ideas.

    Session 4: way forward for influenza surveillance and next steps for WHO

    Based on the feedback from participants at this consultation the following list summarizes the key tasks that WHO will consider as it plans for the future of the global influenza programme:
    • Develop a surveillance evaluation tool to help countries evaluate their systems and make decisions on how to build and maintain surveillance activities as funding changes
    • Initiate pilot studies for severity assessment
    • Advocate for more influenza data-sharing and integration of more analysis tools in FluNet and FluID
    • Determine key parameters for decision-making by country officials and create generic advocacy material that can be customized by countries
    • Develop a right-sizing guidance for the appropriate number of sentinel sites and the prioritization of samples
    • Develop tools and training for risk communication based on surveillance data
    • Develop cost-saving protocols for SARI surveillance
    • Develop epidemiology data management, analysis and reporting tools and training materials
    • Explore ways to make systems more automated, using already collected data (without removing the human component that would identify unusual results)

    General discussion points and messages
    • Encouragement of the quality over quantity in surveillance systems might help many countries to maintain their systems.
    • Integration of systems may be important for sustainability, overcoming the vertical funding model and making them more robust with more than one funding source. WHO can encourage donors to support the backbone of surveillance and reduce duplication of systems.
    • Sharing of surveillance data is important for advocacy and for understanding the influenza situation worldwide.