במדבר יט:כב פירוש: רש״י, רשב״ם, רבנו בחיי וSiftei Chakhamim

וכל אשר יגע בו הטמא AND WHATSOEVER THE UNCLEAN PERSON TOUCHETH — i.e., this unclean person who has become unclean by reason of a corpse, SHALL TOUCH, יטמא SHALL BECOME UNCLEAN.

והנפש הנוגעת, a third party who had had direct contact with someone had had direct contact with the deceased, תטמא עד הערב, will become ritually defiled only until the evening of that day (and can immerse himself in a ritual bath to regain ritual purity).

וכל אשר יגע בו הטמא יטמא, והנפש הנוגעת תטמא, “Anything which the contaminated person will touch shall become contaminated, and the person who touches him will become contaminated.” The meaning of the words והנפש הנוגעת is: “a person who touches another who has been contaminated by direct contact with the corpse will also be contaminated.”