Week 15/2019 (8–14 April 2019)

• Of 41 countries reporting on geographic spread, 5 reported widespread activity. Specimens collected from individuals presenting with ILI or ARI to sentinel primary health care sites yielded an influenza virus positivity rate of 20%, a further decrease for the fifth week in a row.
• Of 41 countries reporting on influenza activity, 40 reported baseline or low intensity levels and 1 reported medium intensity.
• Influenza type A viruses dominated with more A(H3N2) than A(H1N1)pdm09 viruses being detected among sentinel and non-sentinel source specimens. Very few influenza B viruses were detected.
• Of the subset of specimens from patients with severe acute respiratory infection (SARI) collected in week 15/2019 that were tested for influenza viruses, 16% were positive and all viruses were type A.
• Pooled data from 23 Member States and areas reporting to the EuroMOMO project indicated that the all-cause excess mortality observed in previous weeks has returned to normal levels.

2018/19 season overview 

• Influenza activity in the European Region, based on sentinel sampling, exceeded 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, and of those subtyped, 67% were A(H1N1)pdm09. Among influenza virus-infected patients admitted to other wards, 99% were infected with type A viruses, with 56% of those subtyped being A(H1N1)pdm09.

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

• A recent 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.

• WHO has published recommendations for the composition of influenza vaccines to be used in the 2019–2020 northern hemisphere season. The recommendation was that type B lineage viruses remain unchanged, while the A(H1N1)pdm09 and A(H3N2) viruses were updated.

• Circulating viruses in the European Region remained susceptible to neuraminidase inhibitors supporting use of antiviral treatment according to national guidelines.