Use of the word pandemic has also increased by more than 57,000% this year.
Oxford Languages and Collins each decide their own word of the year, and in 2020 Collins chose "lockdown".
But Oxford decided it was an unprecedented year with too many contenders, so expanded its award to encompass a handful of newly key words including lockdown, bushfires and Covid-19, as well as Black Lives Matter, WFH [working from home], keyworkers and furlough.
This year's Oxford-winning word, vax, was first recorded in English in 1799, while its derivatives vaccinate and vaccination both first appear in 1800.
All of these words ultimately come from the Latin word vacca, which means cow. According to the OED, this is due to English physician and scientist Edward Jenner's pioneering work on vaccination against smallpox using cowpox - a mild infection that occurs in cows - in the late 1790s and early 1800s.
Oxford Languages says its corpus, or language resource, gathers news content which is updated daily and contains over 14.5 billion words for lexicographers to search and analyse.