https://www.baishavaad.org/ill-prepared-avoiding-something-like-the-plague/It's interesting to denote how these piskey halacha were made.
Rama insists that with certain limited exceptions, no diseases are actually contagious, “for Hashem is the Smiter and the Healer,” and that is why we find no distinction in the laws of visiting the sick between contagious and noncontagious diseases.[8] Rav Azulai, too, insists that in times of plague, one must visit the sick and bury the dead. He agrues that arguing that as outbreaks of plague typically lasted several months, inattention to the victims will result in grievously unsanitary conditions. He explains that the level of risk involved is acceptable; that “Hashem watches over fools;” and that He does not place the world in intolerable situations. He recommends that one trust in Hashem and avoid sin (particularly gazing at the faces of women).[9] R’ Chaim Palagi, however, strongly disagrees, asserting that plague most definitely is contagious, as evinced by both empirical evidence as well as various comments of the Rishonim,[10] and that flight and avoidance are certainly the prudent course.[11] The Shulchan Gavo’a also strongly rejects the position of Rama, declaring that the custom is that ordinary members of the public do not visit plague victims, and only special groups who are well compensated for doing so visit them.[12]
One would have to accept based on Rabbi palagi opinion of avoidance that minyan is forbidden.
