I handled a lot of 1915-1918 American ammo at a Scranton,PA show and later, in the car, decided to eat potato chips, without washing hands. Then I thought of Spanish flu and decided to postpone eating. Has there been a medical case of disease transmission through ammunition, flu or anything else?
Viruses & bacteria can’t live for more than a few weeks outside a host. Most of them die within a day or two outside a body - so no worries. You can lick those 1918 cartridges if you want to. You’d be more apt to catch a common cold from all the people who sneeze and cough, and then handle cartridges before you that you also touch within an hour.
What about money? We handle that every day and don’t even think about it.
Always the problem of lead ingestion, by mouth or nose.