By RAF CASERT and CARLA K. JOHNSON
Brazil and Japan joined the rapidly widening circle of countries to report cases of the omicron variant, while new findings indicate the mutant coronavirus was already in Europe close to a week before South Africa sounded the alarm. It highlights the difficulty in containing the virus in an age of jet travel and economic globalization. And it leaves the world once again whipsawed between hopes of returning to normal and fears that the worst is yet to come. Much remains unknown about the new variant, including whether it is more contagious, whether it makes people more seriously ill and whether it can thwart the vaccine.