The Israelites knew plague.
“Tzaarat,” whose diagnosis and management is described in Leviticus 13 and mentioned in Deuteronomy 24:8, is the name of a group of skin diseases, and is usually translated as “leprosy” – Hansen’s disease – but it is not Hansen’s disease, which doesn’t seem to have actually been present in Israel in biblical times.
Rabbinical teaching sees tzaarat as a physical manifestation of spiritual failing, yet the Torah itself says nothing of this: tzaarat is the name for a physical disease for which Leviticus 13:1-46 give a protocol for diagnosis, treatment, and management. Leviticus 13:47-59 describes identifying tzaarat in cloth. Deuteronomy 24:8 advises victims to follow the instructions of the Levite healers. Perhaps the ancients thought that skin and cloth rotted in similar ways, or perhaps tzaarat was caused by a fungus which also affected fabric. Scientific medical commentators cannot identify tzaarat; it may not be a currently active disease, or it may be so rare as to be relegated to obscure papers and texts.
Leviticus 13 describes a protocol of isolation, examination, and monitoring for tzaarat. (One commentator even gives a flowchart of the protocol.) In extreme cases, when the disease would not heal, the victim was pronounced tame (טָמֵא, taw-MAY), unclean, and required to isolate themselves until they healed.
What has this to do with modern Christians? The Old Testament recognizes the existence of physical disease and the need for diagnosis and quarantine as appropriate: god did not prevent disease. When modern Christians say that god will protect them against COVID-19 and that there is no need for precautions, distancing, or quarantine, they are adopting an unbiblical stance. Deuteronomy advises victims to do the equivalent of following their doctor’s orders. When Christians say that they do not need to do so because god will protect them, or that quarantine is an infringement on their rights, you can answer them that the Israelites knew plague, and that their own laws told them to quarantine if necessary.