COVID-19 reinfections among people who’ve already battled the virus appear to be more likely with the Omicron variant than other strains, South African scientists warned Friday. A surge in coronavirus reinfections occurred in the country as the new “variant of concern” emerged, according to the National Institute for Communicable Diseases, which tracks reinfections. By contrast, there was no reinfection spike upon the arrival of other variants such as the highly contagious Delta strain, the scientists told the World Health Organization on Thursday. “Previous infection used to protect against Delta, and now with Omicron, it doesn’t seem to be the case,”...