The flu has not disappeared: Understand what happened last year
The flu went almost unseen last winter. During the first 22 weeks of the 2020/2021 flu season in the Northern Hemisphere – between October 2020 and February 2021 – the World Health Organization (WHO) European Region tested 25,606 specimens (1). Only 33 of them tested positive for the flu virus (1).
The amount of flu virus detected was 99.8% lower than during the same weeks in the previous five flu seasons (1). During those seasons, an average of 14,966 specimens tested positive (1).
So, why was the level of flu virus in circulation so low last winter?
The flu and COVID-19 spread through similar routes (2). Direct contact and droplet transmission are the main routes, with aerosol transmission also likely to play an important role (2). It, therefore, stands to reason that the measures imposed to reduce COVID-19 transmission also stopped the flu from spreading (2).
With that in mind, experts believe the extremely low levels of flu virus circulating were mainly due to the measures imposed in response to the COVID-19 pandemic (2)(3). After all, exceptional social distancing measures along with travel restrictions imposed across almost every corner of the world kept us all apart (2)(3).
Flu vaccination rates also likely contributed to the low levels of virus circulating. Health authorities sought to minimise flu infections and keep people at risk of flu complications out of hospital (3), leading to higher than average flu vaccination rates in 2020. The unprecedented increase in demand for flu vaccines led to manufacturers supplying on average 30% more flu vaccine doses in Europe for the 2020/21 flu season (3).
The flu hasn’t gone. And while flu activity was very low during the last flu season, the flu will, without doubt, return. The best thing we can do is protect ourselves and our loved ones by getting our flu vaccine.
Sources
(1) https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.11.2100221
(2) https://acmedsci.ac.uk/file-download/474780
(3) https://www.vaccineseurope.eu/news/press-releases/implementation-of-influenza-vaccination-campaign-2021-22
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