Week 21-25/2019 (20 May–23 June 2019)

  1. Influenza activity was at interseason levels.
  • Of specimens reported from sentinel sources, 1.6% tested positive for influenza. Of SARI specimens tested for influenza, 3% were positive.

  • During the summer, influenza reports will be published on 28 June, 16 August and 4 October. Weekly reporting will resume on 11 October 2019 for the 2019–2020 season.

2018/19 season overview 

  • Influenza activity in the European Region, based on sentinel sampling, reached a positivity rate of 10% in week 49/2018, exceeded 50% between weeks 3/2019 and 7/2019, and peaked in week 5/2019.

  • Both influenza A virus subtypes have circulated, with co-circulation in some countries, while others reported dominance of either A(H1N1)pdm09 or A(H3N2) viruses.

  • Among hospitalized influenza virus-infected patients admitted to ICU wards, 99% were infected with type A viruses, with 66% of those subtyped being A(H1N1)pdm09. Among influenza virus-infected patients admitted to other wards, 99% were infected with type A viruses, with 54% of those subtyped being A(H1N1)pdm09.

  • Of the patient specimens from SARI surveillance that tested positive for an influenza virus, 99% were type A viruses, with 79% of those subtyped being A(H1N1)pdm09.

  • A summary of regional activity from October 2018 to February 2019 was published in Eurosurveillance and can be found here.
  • Current influenza vaccines tend to work better against influenza A(H1N1)pdm09 and influenza B viruses than against influenza A(H3N2) viruses. For more detail, see the Vaccine effectiveness section located under Virus Characteristics.

  • WHO has published recommendations for the composition of influenza vaccines to be used in the 2019–2020 northern hemisphere season. The recommendation states that both type B lineage viruses should remain unchanged, while the A(H1N1)pdm09 and A(H3N2) viruses should be updated.
  • The vast majority of circulating viruses in the European Region were susceptible to neuraminidase inhibitors supporting use of antiviral treatment according to national guidelines.

Influenza intensity, spread and dominant virus type/subtype