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?