I just did a google news search on the word "jab" and most of the results were British/European. Turns out, that's what the Brits call a vaccination shot: https://www.theguardian.com/books/2021/feb/04/why-do-we-call-vaccinations-jabs https://www.nytimes.com/2021/03/19/briefing/atlanta-shootings-ncaa-mens-division-teen-vogue.html The Washington Post has used both terms...might depend on who is reading the article and from where they are reading it. Here is a headline from the 18th: https://www.washingtonpost.com/health/2021/11/18/covid-vaccine-kids-first-dose/ They use both terms in the article - shot (10) and jab (1). In this case, I am guessing they just didn't want to use "shot" twice in the same sentence: And although more Americans have been getting vaccinated, logistical problems have frustrated parents trying to immunize their kids (in one New York City vaccination site, for instance, parents reportedly waited six hours to get their children vaccine jabs), while confusion over who qualifies for boosters has disrupted administrations of the extra shots in some states.