We know how most contagions spread - usually by contact, inhalation, or ingestion. Standard protocols are intended to reduce this risk under normal circumstances.
Policies - These generally refer to contraindications. That is, NOT treating someone when they have certain conditions, or NOT treating local areas, depending on the condition. It is always best to talk to your doctor about any disease you have that may be passed on to others, and to disclose these to your therapist, or you may be held liable for consequences. It also means that if you are ill, you should not be treated. These policies also apply to the therapist!
Hygiene - This generally refers to specific things that are done to maintain cleanliness. It includes the therapist washing hands before/after treatment, changing linens between treatments, cleaning commonly touched surfaces between treatments, and regular cleaning of facilities.
In my case, it also includes Much More. I use a Full Premises Medical Grade Hyper-HEPA air purifier in the treatment room, plus another one elsewhere in the premises (pores are 100x SMALLER THAN A VIRUS). An ultraviolet light is used to disinfect the treatment room, between patients. All commonly touched surfaces are cleaned between patients, including door handles, washroom facilities, etc. Feel free to ask about these measures.
While traditional massage normally entails skin to skin contact, MAT(E)™ treatments reduce the risk because such contact is minimized when the patient keeps their clothes on.