The Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) was established in 2003 to formalise the network of collaborating national influenza reference laboratories participating in the European Influenza Surveillance Scheme (EISS).

From 1 September 2008, the coordination of influenza surveillance activities was transferred from EISS to the European Centre for Disease Prevention and Control (ECDC) with the network being renamed European Influenza Surveillance Network (EISN).  The main tasks of EISN are to report on the influenza activity in the community by analysing routine epidemiological and virological data reported by Member States and to contribute to improving surveillance and laboratory preparedness for seasonal and pandemic influenza.  The concept of the CNRL set up under the EISS project was retained in the new EISN programme to focus on further developing influenza reference laboratories cooperation. 

The CNRL laboratory network comprises of nominated expert representatives from laboratories within 27 EU Member States and two EEA countries (Norway and Iceland) (Figure 1).

Figure 1.  Map of influenza laboratories participating in the CNRL (click on the picture for full width)

The main objective of the network is to carry out virological surveillance of human influenza and ensure that data are shared through EISN reporting mechanisms in a timely manner. Of the 27 EU Member States and two EEA countries that comprise the CNRL network, only Cyprus has a national influenza reference centre not recognised by WHO as a National Influenza Centre (NIC).

Coordination of the CNRL
Since 2008, ECDC has outsourced the coordination of the CNRL through a call for tender to a CNRL Coordination Group made up of a consortium representing three European Institutes: 

• the Health Protection Agency (HPA), London (Professor Maria Zambon), 
• the National Institute of Public Health and the Environment (RIVM), The Netherlands (Dr Adam Meijer), and 
• the WHO Collaborating Centre (WHO CC), MRC National Institute for Medical Research (NIMR), London (Dr Rod Daniels and Dr John McCauley).

CNRL mechanisms of working
The CNRL Coordination Group has aimed to capitalise on the expert experience within network laboratories by continuing to use dedicated Task Groups to complete specific activities.  This model of working has facilitated discussion, enhanced working relationships within the network by sharing best practices and harmonising technical approaches, and ensured inclusivity. The CNRL Task Groups participate in regular teleconferences and a face-to-face meeting each autumn.  A wider meeting of all EISN virologists takes place once a year at the EISN Annual General Meeting.

Collaboration with WHO
Most of the CNRL laboratories are also WHO-recognised National Influenza Centres (NIC). They are supported by the WHO collaborating centre for reference and research on influenza, London, UK. The NICs participate in the Global Influenza Surveillance and Response System (GISRS). The EU/EEA Member State CNRL laboratories report their surveillance data to The European Surveillance System (TESSy) database hosted at ECDC. From TESSy, the data are transferred through machine-to-machine webservices to the EuroFlu database hosted by WHO Europe from where they are shared with the global WHO FluNet. All European NICs have agreed to the Pandemic Influenza Preparedness (PIP) Framework and to its influenza virus traceability mechanism (IVTM),  as have their national governments through the World Health Assembly May 2011 (Motion 64.5)