Hazrat Waleed bin Abdullah narrates that the Noble Prophet (peace and blessings be upon him) passed by a person afflicted with leprosy, so the Prophet (peace and blessings be upon him) covered his nose. He (peace and blessings be upon him) was asked: O Messenger of Allah (peace and blessings be upon him)! Did you not say: There is no reality in contagion, and there is no reality in bad omen? The Prophet (peace and blessings be upon him) replied: Yes, indeed.