Is it permissible to refrain from shaking hands when diseases are widespread, in adherence to the principle of "no harm and no reciprocating harm" and in order to preserve public health?

Shaking hands is not obligatory, but it is a recommended virtue between a man and a man, a woman and a woman, and a man and his unmarriageable kin (mahram), due to the forgiveness of sins it entails. It must be avoided when there is a fear of harm or the transmission of disease, because a Muslim is commanded to be cautious of what harms him, and obligations are forsaken out of fear of harm.