Usage of quotation marks

Question

I have a question about the usage of quotation marks in the following passage:

The Democratic Republic of Congo has cleared the way for the World Health Organization to deploy a trial vaccine against a deadly outbreak of Ebola in the northwestern part of the country. WHO has a stockpile of the vaccine, which is made by Merck and was highly effective against Ebola in Guinea in 2015. Though not fully licensed yet, the vaccine is available under an “expanded access” program for use in emergencies. WHO officials expect the first of 4,000 requested vaccines to arrive this week near the town of Bikoro. It is hard to get there, however, and the shots must be stored in extremely cold temperatures, so the project will be challenging.

So far, there have been 39 confirmed or suspected Ebola cases — only two have been verified by a lab — and 19 deaths tied to the outbreak. The vaccines will be given to “rings” of people that include contacts of infected persons, the contacts of those contacts and front-line health workers. Participation is free and voluntary, and people who refuse the shot will not be denied health services if they need them.

Here, the writer uses quotation marks for "expanded access" and "rings", but I do not understand why the person used them. I searched for the uses of the marks, and usually it says quotation or direct speech, mention in another work of a title and scare quotes.

In English writing, quotation marks are placed in pairs around a word or phrase to indicate: Quotation or direct speech: Carol said "Go ahead" when I asked her if the launcher was ready.

Mention in another work of a title of a short or subsidiary work, like a chapter or episode: "Encounter at Farpoint" was the pilot episode of Star Trek: The Next Generation.

Scare quotes, used to mean "so-called" or to express irony: The "fresh" apples were full of worms. Wikipedia

But I do not think they are any of the above usage. Could you please help me?

Answer 1

The quotation marks are being used to denote "words as words" in an attributive sense. (As I just did.)

In fact, so-called can also have this meaning:

So-called:

[attributive] Used to show that something or someone is commonly designated by the name or term specified.
‘Western Countries belonging to the so-called Paris club’

So, in your sample passage, it could have been written as "vaccines will be given to so-called rings of people . . ." However, without the quotes it might not be clear if it's rings of people or just rings that is being called out. For clarity, quotes should be put around rings—and if that's done, using so-called becomes redundant.

Using so-called for irony follows in a second definition:

Used to express one's view that such a name or term is inappropriate.
‘she could trust him more than any of her so-called friends'

But taking the example in the first definition, and going back to quotation marks, it could also have been written as:

Western Countries belonging to the "Paris club."

In terms of formatting, The Chicago Manual of Style (7.63) says:

When a word or term is not used functionally but is referred to as the word or term itself, it is either italicized or enclosed in quotation marks. . . . Although italics are the traditional choice, quotation marks may be more appropriate in certain contexts. In the first example below, italics set off the Spanish term, and quotation marks are used for the English (see also 7.53). In the second example, quotation marks help to convey the idea of speech.

The Spanish verbs ser and estar are both rendered by “to be.”
Many people say “I” even when “me” would be more correct.

Answer 2

Quotation marks are also used to mark certain words and phrases for some kind of emphasis, in this case to indicate what some other unspecified person called them. It can also indicate this is an uncommon use of the terms "expanded access" and "rings".

Another example:

Before first using the software you will need to edit the "global properties" file and set the "home" and "target" directories.

Here I quote the selected terms to emphasize what the writers of the software called the file, and the values in the file. It's a kind of quote, but a very small fragment.