A method for reducing risk of infection from microorganisms for certain elevated-risk individuals, includes: administering a barrier-forming composition in a therapeutically effective amount to a surface, the surface comprising a mucosa, or a mucosal or skin lesion of an individual. The individual has an elevated risk condition selected from: an elevated risk of being exposed to harmful viral, bacterial, or fungal microorganisms； a condition causing an elevated risk of infection from viral, bacterial, or fungal microorganisms； and an elevated risk of serious complications resulting from an infection caused by viral, bacterial, or fungal microorganisms. The method includes forming a barrier coating on the surface that is active to trap, and kill or neutralize microorganisms encountered by the barrier coating and effectively reducing the microbial load on the surface and continuing to administer the barrier-forming composition in a therapeutically effective amount to the surface, for one time or more in a 24 hour period.
