Weekly influenza update, week 42, 2017
ECDC and WHO/Europe publish weekly influenza surveillance data in the report Flu News Europe. This report covers the period week 42 (9-15 October) 2017.
Week 42/2017 (16 – 22 October 2017)
- Of the 40 countries reporting on influenza activity, 39 reported low intensity, while Malta reported medium intensity.
- Only 14 sentinel specimens tested positive for influenza. Two thirds of detected viruses were type A and one third type B. Overall, 3% of sentinel specimens were positive for influenza virus.
- Data from the 19 countries or regions reporting to the EuroMOMO project indicated all-cause mortality to be at expected levels for this time of the year.
2017/18 season overview
- Since week 40/2017, low numbers of influenza viruses have been detected in sentinel specimens but, of all typed viruses, the proportion of type A viruses has been increasing and reached 64% in week 42/2017.
Due to the diversity of A(H3N2) influenza viruses that circulated during the 2017 Southern Hemisphere season and reports of low vaccine effectiveness (17% against A(H3N2) overall), WHO recently recommended a change of the A(H3N2) component for inclusion in seasonal influenza vaccines for use in the 2018 Southern Hemisphere influenza season. In addition, the influenza B lineage in trivalent vaccines was changed to a B/Yamagata-lineage virus, compared to the vaccine component (a B/Victoria-lineage virus) recommended for 2017–2018 Northern Hemisphere influenza season.