2021-2022 season

• For the Region as a whole, influenza activity reached levels well above that observed in the 2020/21 season.
• Influenza activity, based on sentinel primary care specimens from patients presenting with ILI or ARI symptoms, first peaked in week 52/2021 (when it reached 19% positivity), declining thereafter until week 4/2022, when it increased again reaching a plateau phase (25-30% positivity) between weeks 10 and 15/2022 (this represents late activity compared to most previous seasons) followed by a subsequent 3-week decline.
• Different levels of activity have been observed between the countries and areas of the Region, with a dominance of A(H3) viruses in most countries.
• During the influenza Vaccine Composition Meeting for the northern hemisphere 2022/23 season, held in February 2022, WHO recommended updating of the A(H3N2) and the B/Victoria-lineage components. The full report can be found here.
• The European I-MOVE network estimated influenza VE using a multicenter test-negative design among symptomatic patients presenting at primary care level between October 2021 and March 2022. Preliminary influenza VE against influenza A among seven study sites and among all ages was 36% (95%CI: 13–53) and 41% (95%CI: 15–59) among those aged 18–64 years. All-age VE against influenza A(H3N2) was 35% (95%CI: 6–54) and 37% (95%CI: 3–59) among those aged 18–64 years. There were too few influenza positive cases among other age groups to allow VE estimations.
• In Sweden, the vaccine effectiveness against laboratory-confirmed influenza was estimated to be 47% for individuals over 65 years of age.
•  According to preliminary data in mainland France, the VE was estimated to be 50% (95% CI: 14-71) against all circulating influenza viruses, 77% (95% CI: 36-92) for A(H1N1)pdm09 and 31% (95% CI: -29-64) for A(H3N2).
• For children aged 2 to 6 years in Denmark, the estimated VE against influenza A viruses was estimated at 63% (95% CI: 10.9–84.4) in those hospitalized, and 64% (95% CI: 50.5–74.1) in those not hospitalized.
• Preliminary results of 2021-2022 seasonal influenza vaccine effectiveness (VE) estimates from the United States showed that VE against medically attended outpatient acute respiratory infection associated with the dominant circulation influenza A(H3N2) virus was 16% (95% CI = -16% to 39%).
• With increased circulation of influenza virus clinicians should consider early antiviral treatment of patients in at-risk groups with influenza virus infection, according to local guidance, to prevent severe outcomes. The majority of viruses analyzed so far have remained susceptible to neuraminidase inhibitors and baloxavir marboxil.

Other news

For information about the SARS-CoV-2 situation in the WHO European Region visit:

• WHO website: https://www.who.int/emergencies/diseases/novel-coronavirus-2019
• ECDC website: https://www.ecdc.europa.eu/en/novel-coronavirus-china

For the European Region, influenza virus positivity in sentinel primary care specimens decreased from 17% in the previous week to 14% but is still above the epidemic threshold which is set at 10%.

Mortality monitoring

In week 18/2022 overall pooled EuroMOMO estimates of all-cause mortality for the participating European countries showed decreasing, but still elevated, excess mortality among the elderly (65 years or older) and among older adults (45 to 64 years of age). Data from 26 European countries or subnational regions were included in the week’s pooled analysis of all-cause mortality. The full EuroMOMO report can be found here:  https://www.euromomo.eu/.