Risk assessment of seasonal influenza, EU/EEA, 2016/2017, 24 December 2016

Risk assessment

European Centre for Disease Prevention and Control. Risk assessment of seasonal influenza, EU/EEA, 2016/2017 –24 December 2016. Stockholm: ECDC; 2016.

​Since the 2009 influenza pandemic, ECDC has produced early-season risk assessments for EU/EEA countries every season, to inform national public health authorities of the key attributes of the ongoing influenza season. These risk assessments, based on weekly clinical epidemiological and virological data from primary and secondary healthcare settings, provide an early description of the epidemiological pattern of seasonal influenza in the first affected countries and anticipate the progression of influenza activity and the possible impact on susceptible and at-risk populations for the rest of the season.

Executive Summary

Seasonal influenza comes early in the EU/EEA

Seasonal influenza has begun early in the 2016/2017 season with A(H3N2) as the dominating virus. At this stage, it is too early to anticipate what the consequences will be for primary and secondary care, but if the A(H3N2) strain continues to dominate, people over 65 years of age may be the most severely affected, possibly putting some national healthcare systems under pressure. ECDC published a rapid risk assessment reviewing the season so far.

To prevent severe cases, vaccination of the elderly and other high-risk individuals remains a priority in line with national recommendations:

“People who are recommended to have the influenza vaccine by their national authorities should get vaccinated. Normally vaccination should be undertaken in the autumn, before the flu season begins in order to maximise benefit, but high risk groups, notably people over 65 years of age, can still benefit from being vaccinated in January and February”, says Mike Catchpole, Chief Scientist at ECDC.

Vaccine effectiveness is always partial and neuraminidase inhibitors for laboratory-confirmed or probable cases of influenza should be considered as an option for vaccinated and non-vaccinated patients at risk. The current information shows that the circulating influenza viruses are in line with the influenza vaccine components.

In A(H3N2)-dominated seasons, older people have been affected the most, resulting in a high number of hospitalised cases and an increase in fatal outcomes in this age group. This was also seen during the 2014—2015 season, with a high number of outbreaks in long-term care facilities and excess all-cause mortality. Should the A(H3N2) virus remain predominant in most countries older age groups would likely be the most affected and the most at risk of severe disease and outcomes.

Since the start of the season, 69% of influenza patients hospitalised in intensive care units were aged 65 years or more, where that information is available.

ECDC, along with WHO Europe, monitors seasonal influenza and produces weekly updates. For more information see Flu News Europe