Ключевые слова: bacteria, bacterium, blue, chalkboard, closeup, concept, copy, danger, defense, epidemic, female, flu, hand, health, holding, hygiene, immune, immunity, immunodeficient, immunology, immunotherapy, infection, infectious, medical, medicine, ncov, pandemic, person, prevent, prevention, protection, safety, small, space, support, system, text, vaccination, virus, woman, word,