感染(かんせん)
It simple means "infection" and by adding additional kanji you can create related terms like with 症 it makes it an "infectious disease" (感染症). Adding 者 makes it an infected person (感染者). That list can get long, so just more additional example with 爆発 (explosion) added: It becomes 感染爆発 (explosive growth of infections).
不要不急 (ふようふきゅう)
It literally means "not necessary and not urgent". I saw it used in the first articles when people in Tokyo and around where advised to stay at home on the weekend. Interesting is here also the structure of 不*不* of which the Japanese language certainly has several examples. Me, as a Dragon Ball fan, know the pattern from 不老不死, which literally means "not aging and not dying".
延期(えんき)
As the Coronavirus causes several events to be postponed, you'll find 延期 quite often.
As the Coronavirus causes several events to be postponed, you'll find 延期 quite often.