The people of Jāhiliyyah considered sneezing to be a disease and treated it as an omen. However, sneezing is in fact a healing and blessing from Allāh for which He is praised
Its summary is that “There is no contagion” is upon its apparent meaning, and that the command to flee from the leper is carried upon recommendation...
The Caliph ʿUmar would seek to push out and repel any notion or idea of contagion from his mind, in order to gain certainty in the statement of the Prophet [sas] in negation of the superstition of contagion.