I almost always use upper case when I am using obvious acronyms, so it is WHO, NASA, NATO, AIDS, and so on. But I have noticed in reading news articles from some but not all sources that certain acronyms are written as if they are just nouns, as in the case of Nato and Nasa. For example, this article from the Guardian refers to the National Oceanic and Atmospheric Administration as Noaa and to the Virginia Institute of Marine Science as Vims. Similarly, this article from the BBC refers to Nasa. But the BBC, WHO, NFL, and the NBA are always kept as upper case.
Kevin Drum was also puzzled by this variance in the context of how different media outlets referred to the virus causing the pandemic. It was written as COVID-19, Covid-19, or covid-19 and upon investigating further found that of 15 major American news outlets, the score is 9-6 in favor of keeping it as all caps.
What about sometimes capitalizing just the first letter of the acronym?
In case you’re wondering, British style is to use uppercase for acronyms that are pronounced as separate letters when spoken but lowercase for acronyms that are pronounced as words when spoken. So NASA is Nasa and COVID is Covid, while FBI is FBI and USA is USA.
So that explains it. I myself think it preferable to always capitalize all the letters in an acronym, whether they can be spoken as a word or not. Seeing Nasa and Nato is jarring.
According to Merriam-Webster, an acronym is “a word (such as NATO, radar, or laser) formed from the initial letter or letters of each of the successive parts or major parts of a compound term.” Even though all three acronyms given as examples can be spoken of as words, just the first one is capitalized. This may be because the other two have long since become so common that many people may not even recognize that they are acronyms in which each letter stands for a word. The acronym has transitioned into a regular word.
What about covid-19? It is the identifier for the disease caused by a particular virus though the virus is also sometimes referred to by the same label. Should we treat it as an acronym for COronoVIrus Disease, in which case I should be using COVID, or is it just a new word? Merriam-Webster refers to Covid as a noun, unlike for NASA that it refers to as an abbreviation, suggesting that it should be treated as a word.
If it is the name given to a disease, then we should perhaps just refer to it entirely in lower case as covid-19, like we do with all other diseases that are not named after people, such as measles or diphtheria.
Clearly I have way too much time on my hands to be thinking about things like this …