To protect herself and others from potential infectious diseases, she must wear

She must wear a mask and gloves.

The mask would prevent her from inhaling pathogens that get transferred viraly, while latex gloves would prevent pathogens from entering through her skin, or if she later decides to put her fingers in her mouth or anything similar.

If she has a wound on her hands, the gloves will also prevent the blood from mixing with her own and prevent disease.