I can't always wash my hands with soap and water. I work as a cashier and work with money all day, so many microbes pass through me. I have to use antiseptic gels. But my hands began to deteriorate from frequent use. Dry steels and crack sometimes.
In fact, it is extremely unlikely to catch a serious illness through money, paper, metal, because all banknotes are treated with bactericidal compounds. The coins are generally coated with a nickel or chrome alloy, which is poisonous for microorganisms (alas, I don’t remember exactly, but the handrails in the subway are made of it). Naturally, some sores, for example, some types of worms or the same Salmonella, hypothetically can be picked up from banknotes, but the likelihood of getting infected by touching street clothes or shoes is greater. For example, you sat in jeans on the subway, and then in the same jeans - at home on the couch. However, the likelihood of catching something is also minimal if you follow the minimum hygiene rules.
Washing your hands after any contact with money, however, will not be superfluous. In addition, be careful with old banknotes of small denomination - most likely, they have been in different hands, and the protection has already "fallen off" from them.
Through money, you can "pick up" dangerous diseases, such as: fungal diseases, salmonella, worms, E. coli, staphylococcus.
All these diseases are quite serious. For example, staphylococcus aureus brings not just health problems, but very big troubles - from damage to the colon and abdominal pain to acne on the skin. The notorious phrase - “wash your hands before eating” is a very useful warning after money has been in your hands.