Word of the year 2021 (Merriam-Webster): Vaccine

 from Merriam-Webster dot-com In everyday use, words are useful tools that communicate assertions, ideas, aspirations, and uncertainties. 

But they can also become vehicles for ideological conflict.

• This is what happened to vaccine in 2021. The promising medical solution to the pandemic that upended our lives in 2020 also became a political argument and source of division. The biggest science story of our time quickly became the biggest debate in our country, and the word at the center of both stories is vaccine.

  Hopes for cures and treatments of COVID-19 began as soon as the disease began to spread. Research into a new kind of vaccine containing messenger RNA, or mRNA, genetic material rather than an inactivated form of the virus was accelerated. After decades of studies conducted for application to diseases such as influenza, Ebola, and rabies, this new type of mRNA vaccine against the SARS-CoV-2 virus was rapidly developed, tested, and manufactured for broad use, with the first doses being administered in the U.S. in December 2020.

  The use of a vaccine that triggers an immune response in an entirely new way required that Merriam-Webster revise and expand its entry for the word, which the company did in May. The definition, which formerly read “a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease,” was replaced with the following:

  1 : a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease: such as

  a : an antigenic preparation of a typically inactivated or attenuated (see ATTENUATED sense 2) pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin)

  b : a preparation of genetic material (such as a strand of synthesized messenger RNA) that is used by the cells of the body to produce an antigenic substance (such as a fragment of virus spike protein)

  Interest in the definition of this word was intense in the past year: lookups for vaccine increased 601% year-over-year from 2020. But interest in the word has been high since the start of the COVID-19 pandemic, with much discussion of the funding, development, testing, and ultimate distribution of the vaccines occurring in 2020. The prominence of the word vaccine in our lives in this era becomes even more starkly clear when we compare 2021 to 2019, a period in which lookups for the word increased 1048%.

  Lookups of vaccine, already very high all year, jumped by 535% in August, long after discussions about vaccines began taking place in the press and widespread distribution in parts of the world were well underway. A number of stories in August show that discussions about policy, approval, and vaccination rates—rather than the vaccine itself—sent people to the dictionary. During this period, New York and California instituted vaccine mandates for health care workers; a federal mandate was announced for nursing home staff; an announcement of plans for booster shots for the general public in the U.S. prompted condemnations of inequities in vaccine distribution; and full FDA approval for Pfizer’s vaccine was granted.

  This new higher rate of lookups since August has remained stable throughout the late fall, showing not just a very high interest in vaccine, but one that started high and grew during the course of 2021.

  Vaccine comes from the Latin word for “cow,” vacca, because the term was initially used to refer to inoculation using doses of cowpox that, it was discovered, protect humans against smallpox. This word is a relatively recent one in English, dating back to the 1880s. See more on how vaccines work.

  The word vaccine was about much more than medicine in 2021. For many, the word symbolized a possible return to the lives we led before the pandemic. But it was also at the center of debates about personal choice, political affiliation, professional regulations, school safety, healthcare inequality, and so much more.

  Few words can express so much about one moment in time.