Ключевые слова: background, bacteria, bacterium, closeup, concept, danger, defense, disease, epidemic, face, flu, health, immune, immunity, immunodeficient, immunology, immunotherapy, infection, light, mask, medical, medicine, ncov, nobody, notebook, object, pandemic, paper, prevent, prevention, protection, quarantine, safety, stethoscope, support, system, table, virology, virus, white, word, written,