omicron, variant, infection, mutation, africa, ban, booster dose, card, classification, concern, coronavirus, covid, covid-19, covid-19 variant, doctor, epidemiological, epidemiology, evolution, face mask, female, hand, hold, injection, mask, n95, new, new covid variant, omicron variant, reinfection, risk, safety, sars-cov-2, south, south africa, syringe, text, travel, vaccination, vaccine, vial, virus, who, world health organization