Annual Report 2021-2022

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The Foundation for Influenza Epidemiology

The GIHSN is supported by a dedicated fund, the Foundation for Influenza Epidemiology.

The Foundation for Influenza Epidemiology was created in September 2015 by Sanofi under the auspices of Fondation de France to formalize several years of commitment to epidemiological research on severe influenza.

This funding mechanism was established to facilitate additional funding from other donors for this world-scale active surveillance project.

4 new donors have joined the Board in addition to Sanofi: Illumina, Seqirus, Abbott and IFPMA/IVS

All donations collected through this foundation are dedicated to epidemiological research in the field of severe influenza and other respiratory viral diseases.


Foundation governance

The governance of the Foundation for Influenza Epidemiology is ensured by an Executive Committee (EC). The Executive Committee is the decision maker, in charge of the strategic directions related to the project. Based on pre-established criteria, the Executive Committee selects applicant sites for funding allocation each year. The Executive Committee is composed of donors representatives and three independent experts.

Scientific oversight is ensured by an Independent Scientific Committee involving some of the world’s top flu epidemiology/virology/policy experts including representatives from US CDC and WHO.

Coordination of the network and operational implementation, including data collection & hosting, is supported by an independent organization: Impact Healthcare.

Members of the Scientific Committee

Independent Experts:

  • Marta NUNES, CERP, University of Lyon, France (Chair)
  • Bruno LINA, University of Lyon, France (former Chair)
  • Joseph BRESEE, The Task Force for Global Health, USA
  • John McCAULEY, Crick Institute, London, UK
  • John PAGET, Netherlands Institute for Health Services Research, Utrecht, Netherlands
  • Justin ORTIZ, University of Maryland, USA
  • Cecile VIBOUD, Fogarty International Center at the National Institutes of Health (NIH), USA
  • Wenqing ZHANG, Global Influenza Program, WHO, Geneva (Observer)
  • Sandra S CHAVES, Foundation for Influenza Epidemiology, France (Observer)

Site Representatives:

  • Melissa K ANDREW, Canadian Serious Outcomes Surveillance Network, Halifax, Canada
  • Sonia M RABONI, Virology Laboratory, Infectious Diseases Division, Universidade Federal do Paraná, Brazil
  • Xavier LOPEZ LABRADOR, Virology Laboratory, Genomics and Health, FISABIO, Spain


A constructive dialog with WHO Global Influenza Program has been developed. Early February 2023, the GIHSN shared with WHO its first descriptive report presenting phylogenetic threes of circulating influenza strains from hospitalized patients captured by the GIHSN surveillance platform.

It is expected that those sequencing results from 226 influenza cases collected in 11 countries from 1st September 2022 to 1st February 2023 will add disease severity perspective to the large dataset of influenza surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS) and will support the WHO advisory group of experts to issue recommendations on the composition of the influenza vaccines for the following season.



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of the GIHSN

To inform policy decisions, national health authorities need to understand the burden of influenza disease and the impact of current vaccination programs in their countries. The Global Influenza Hospital Surveillance Network (GIHSN) is a platform able to generate strong epidemiological and medical evidence on the burden of severe influenza and the public health impact of influenza vaccines.

The GIHSN was initiated by Sanofi Pasteur in 2011 to fill the gap in epidemiology and public health knowledge. The GIHSN gathers several sites affiliated with national health authorities (see Implementing partners).


According to the World Health Organization (WHO), seasonal influenza epidemics affect an estimated 5–15% of the total population worldwide, with 3–5 million cases of severe illness, resulting in 250,000–500,000 deaths. However, few data are available for many parts of the world where active surveillance is lacking. In addition, the viruses and the severity of influenza epidemics vary greatly between years and geographical areas. To address the rapidly evolving antigenicity of circulating influenza viruses, twice annually, the WHO re-evaluates the viruses that should be included in the seasonal influenza vaccines.

To inform policy decisions, national health authorities need to understand the burden of influenza disease and the impact of current vaccination programs in their countries.

High-quality, active surveillance networks are needed to better understand influenza epidemiology and therefore better control influenza epidemics. Data from existing sentinel physician networks are used in several countries to conduct annual studies on the effectiveness of vaccines in preventing medically attended influenza like illness (ILI). These networks, however, do not collect data on the impact of influenza infection on hospitalization or on the impact of influenza vaccines on influenza-related hospitalization, which substantially influence evaluation of the benefits and cost-effectiveness of influenza vaccines.

Active surveillance networks are also powerful advocacy instruments for highlighting the often-underestimated impact of influenza. While hospital surveillance systems already exist for detecting outbreaks of respiratory viruses, few focus on the actual burden of serious influenza cases using the specific outcome of laboratoryconfirmed influenza ; instead, the burden is most often estimated from hospital databases using criteria prone to various biases.

Rational and scientific objectives

Severe cases of influenza requiring hospitalization are probably the most influential factors in term of flu vaccination advocacy and cost-benefit evaluation of vaccination. In addition, little is known about the effect of influenza vaccine on the prevention of severe disease.

Indeed, previously published studies are prone to various biases. A design based on a network of hospitals is easier to standardize for quality insurance reasons and easier to coordinate than a General Practitioners (GP) network approach. Finally the availability of diagnostic capacities at hospital make influenza case ascertainment more reliable.


The GIHSN has three main objectives :

  1. Evaluate the burden of severe influenza disease, defined as hospitalization related to community-acquired influenza or complications following an influenza infection;
  2. Quantify the distribution of the different influenza viruses (A(H1N(H3N2), B/Yamagata, and B/Victoria) among these severe cases; and
  3. III. Measure the effectiveness of influenza seasonal vaccines to prevent these hospitalizations using a test-negative design.


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