There is a common thread that Jews historically suffered less from epidemics because of Jewish ritual requirements of cleanliness.
E.g., Wikipedia - Perceived Jewish immunity has 3 weakly supporting references:
- The Black Death: "The Christians claimed that the Jews died at only half the rate. Even if true, it would then be about 20% of the Jewish population who died from the plague."
- Pasachoff, Naomi E.; Littman, Robert J. (2005). A Concise History of the Jewish People. Lanham: Rowman & Littlefield. p. 154. ISBN 0-7425-4365-X: "However, Jews regularly ritually washed and bathed, and their abodes were slightly cleaner than their Christian neighbors'. Consequently, when the rat and the flea brought the Black Death, Jews, with better hygiene, suffered less severely ..."
- Joseph P Byrne (2012). Encyclopedia of the Black Death Volume 1. p. 15 "Anti-Semitism and AntI-Jewish Violence before the Black Death": "Their attention to personal hygiene and diet, their forms of worship, and cycles of holidays were off-puttingly different."
However, all these quotes speak of explaining the effect, not of its presence.
My question is about the premise:
Is it actually true that Jews were indeed less affected by a major historical epidemic?
The aforecited wikipedia page also contains a weak refutation of the premise:
Simonsohn, Shlomo (1991). Apostolic See and the Jews. Toronto: Pontifical Institute of Mediaeval Studies, Vol. 1: Documents, 492. p. 1404. ISBN 9780888441096: "Pope Clement VI tried to protect the Jewish communities, issuing two papal bulls in 1348, on 6 July and 26 September, saying that `It cannot be true that the Jews, by such a heinous crime, are the cause or occasion of the plague, because through many parts of the world the same plague, by the hidden judgment of God, has afflicted and afflicts the Jews themselves and many other races who have never lived alongside them'." (no claim is made wrt the rates of infection)