#14,588
While the United States continues to see the early (and unusual dominance) of Influenza B (Victoria), followed by A/H1N1 (see FluView Week 49) the early trajectory of Europe's flu season shows A/H3N2 well in the lead, followed by Influenza B (Victoria).
It is not unusual to see very different flu seasons running concurrently across North America, Europe, Asia, or the Middle East. And the characteristics of each region's flu season are subject to change over the course of the season.Although we won't see any preliminary flu vaccine effectiveness (VE) reports for another month or so, it is likely that the A/H1N1 component will end up being the most protective, while the growing diversity A/H3N2 and B/Victoria viruses in circulation will lower the VE against those strains.
With that in mind, there are some indications that the EU may be facing a particularly rough flu season ahead, and today the ECDC - in conjunction with the WHO - has published an early season situation report.I've reproduced the press release and summary below. The full 11-page PDF may be downloaded for additional details.
Regional situation assessment - Seasonal influenza, 2019–2020
Publication
This situation update for seasonal influenza uses epidemiological and virological data to assess the seasonal increase of influenza cases in relation to disease severity and impact on healthcare systems. It is designed to assist forward planning in Member States.
Executive summary
- First detections for the 2019–2020 season indicate co-circulation of influenza types A (71%) and B (29%) viruses in the WHO European Region. All of the four influenza subtypes and lineages are circulating. Of the types A and B viruses detected, the A(H3) subtype and B/Victoria lineage have been dominant in north-western Europe and Central Asia, respectively.
- Genetically and antigenically diverse influenza A(H3N2) and B/Victoria virus strains are co-circulating in the Region.
- The season has started slightly earlier than usual. It is too soon to predict how the season will develop in terms of peak week, severity and duration.
- A(H3N2) is typically associated with serious health impact in older age groups. Some countries, such as the United Kingdom, are already seeing increased rates of influenza hospitalisation. There is no evidence of significant excess mortality at this early stage, however experience during past seasons suggests a significant mortality impact on the elderly during A(H3N2) dominated seasons.
- B virus circulation might be associated with a higher burden on younger age groups, as already observed in Portugal.
- Continued emphasis on vaccination programmes targeting the elderly and other eligible populations, such as individuals with pre-existing cardio-respiratory medical conditions, is strongly encouraged.
- Surge capacity of healthcare facilities should be reviewed in anticipation of probable increased patient flows in emergency care during the peak influenza weeks.
- The timely administration of neuraminidase inhibitor antivirals following national guidance is recommended to mitigate severe disease outcomes.
- Measures to communicate practices such as self-isolation when ill, respiratory etiquette and hand hygiene should be encouraged.
From the ECDC/WHO assessment
Depending on the epidemiological situation in individual countries, those that have already exceeded their epidemic threshold may experience significant pressures on healthcare services during the upcoming holiday period.
Immediate assessment of surge capacity in emergency departments will facilitate reorganisation of resources during the peak weeks of influenza. Elderly patients are known to be severely affected when A(H3) viruses are circulating and younger adults when A(H1) is circulating. Influenza B viruses have also been associated with high burden to children and adolescents in the past [21].
Special attention should be given to the early diagnosis and appropriate treatment of patients with influenza, particularly those with underlying clinical conditions, in accordance with national recommendations and guidelines [19].
