South African scientists say an explosion of COVID-19 cases around Johannesburg has peaked — just one month after the fast-spreading Omicron variant was first detected in the region. South Africa’s National Institute of Communicable Diseases said Wednesday Omicron appears less likely to cause hospitalizations and death than other variants. Researchers in Scotland and at Imperial College London announced similar findings. It’s not clear whether Omicron is sending fewer people to the hospital because it’s less virulent or because many people have partial immunity due to vaccination or a previous infection.