The first people usually affected by any major crisis are those with major health problems. Band-Aids, Antibiotic topical cream, Gauze, Alcohol, etc. Coated aspirin, acetaminophen, etc. And any type you use on a regular basis. Washing your hands often will prevent more disease than any medicine.
Germs have a field day.
With reduced medical services, it could mean your life. A good maxim to promote health in difficult circumstances is always change your underwear and socks each day and wash out used pair. If you add a bit of koolaid, you've got a Gatorade equivalent. Add koolaid if desired. Depending on your sensibilities, you can use each bag one time or several times.