感染者

an infected person
infected people
フレーズ、可算名詞

One key reason for the low number of infections recorded is that Japan has imposed strict criteria to be eligible for testing, focusing on giving tests only to people who have had sustained fevers for more than four days combined with overseas travel, close contact with an infected person or lung symptoms severe enough to warrant hospitalization.
https://www.japantimes.co.jp/community/2020/04/01/...

Less than 2 percent of the total number of infected people have died from the virus so far but that figure could change.
https://www.aljazeera.com/news/2020/02/infected-co...

ほか、those who 〜を使った表現などもあるはず。