Harmonising the virological surveillance of influenza in Europe: results of an 18-country survey

Abstract

The European influenza surveillance scheme (EISS) is based on a surveillance model that combines clinical and virological data in the general population. Eighteen countries in Europe report weekly influenza activity to EISS (http://www.eiss.org). A questionnaire on the virological data collection was sent electronically to the EISS members. Questions on the specimen collection, representativity, laboratory diagnosis of influenza, reporting of variants, testing for other respiratory infections, serological testing, near-patient tests and preparedness for a pandemic were included. The results of the survey showed that for the typing of influenza, the methods polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA) and haemagglutination inhibition (HAI) methods are used most frequently. For the subtyping of influenza, HAI and PCR are used most often. An east-west divide was seen for the use of PCR in typing and subtyping (more PCR use in the west). Differences in the virological surveillance systems in Europe can make direct comparisons difficult because detection rates may differ by test. For the reporting of other respiratory infections besides influenza, many networks (68%) collect information on RSV. This is important because RSV causes similar clinical symptoms as influenza and can have a similar impact in terms of burden of disease. With the collection of RSV data, EISS is moving to a broader spectrum of viral respiratory diseases. The findings of this survey will be used to better harmonise laboratory methods in EISS in order to obtain more reliable and comparable information on influenza activity in Europe.

Influenza surveillance in Europe: comparing intensity levels calculated using the moving epidemic method

“…Estimated rates based on ILI and ARI consultations showed great variability across countries, most likely due to different health systems, healthcare‐seeking behavior, and surveillance schemes, including case definitions and virological surveillance . The WHO Regional Office for Europe and the ECDC receive weekly information on ILI and/or ARI from surveillance systems using either population or consultation denominators as well as qualitative indicators such as intensity, trend, and geographical spread, by country.…”

Synchrony of Clinical and Laboratory Surveillance for Influenza in Hong Kong

“…A study in UK found only about 30% of specimens from patients presenting with ILI symptoms in a general practitioner's surveillance network were positive for influenza [8] . Laboratory surveillance, which is believed to provide more accurate information about influenza virus activity than clinical surveillance, has been implemented in parallel with clinical surveillance in many regions [9] , [10] . Unfortunately, due to constraints of time and budget, laboratory surveillance tends to be more restricted in scale with relatively smaller numbers of patients being tested with the primary aim of detecting genetic and antigenic changes of circulating strains in order to update influenza vaccines rather than for early warning of influenza epidemics [11] .…”

Morbidity profiles of patients consulting during influenza and respiratory syncytial virus active periods

“…Many of the European primary care-based surveillance networks for monitoring influenza also report on the incidence of RSV infection. However, although these networks investigate for both viruses, they do so in patients presenting with what are generally described as ILI [22]. Whilst not all networks collect data on the basis of strict diagnostic criteria, there is a general consensus of investigating patients with illnesses which include acute onset of respiratory symptoms such as cough accompanied by fever.…”