Did you guys know that there are over 2 billion muslims, and 9/10 muslims don't change underwear every day.
Actually, I was informed that many Muslims don't wear undergarments, particularly the ones living out in the boonies that dress traditionally. Frankly, cotton pants provide a lot more breather room anyways, a lot more comfortable than boxers, for sure.
Also, the plague originated from China/India, so you should be more worried about those parts of the world.
Last of all, Japanese, Koreans and South East Asians consider all other races to be extremely lacking in hygiene and complain endlessly about how bad we (non-East and SE Asians) smell. They're terrified of us.