US health officials are urging Americans to get vaccinated, as research teams try to learn more about a highly mutated new coronavirus variant identified by South African scientists. (Eli Jordan FOX 5 Atlanta)GENEVA - The World Health Organization expressed concerns Thursday that rich countries spooked by the emergence of the omicron variant could step up the hoarding of COVID-19 vaccines and strain global supplies again, complicating efforts to stamp out the pandemic.The U.N.