Influenza has returned to Europe at a faster-than-expected rate this winter after almost disappearing last year, raising concerns about a prolonged "twindemic" with COVID-19 amid some doubts about the effectiveness of flu vaccines.
Lockdowns, mask-wearing and social distancing that have become the norm in Europe during the COVID-19 pandemic knocked out flu last winter, temporarily eradicating a virus that globally kills about 650,000 a year, according to EU figures.
