JOHANNESBURG, South Africa—South Africa’s President Cyril Ramaphosa has denounced travel bans on Southern African nations linked to the new COVID-19 variant and called for an end to the “discriminatory” and “unscientific” restrictions. South African scientists on Nov. 25 revealed they had detected a new, potentially more infectious variant now known as “Omicron.” They tracked the first case to neighboring Botswana and suspect Omicron’s driving a new wave of infections in South Africa’s Gauteng province, which includes its most populous city, Johannesburg. Countries around the world responded by stopping travel to and from southern Africa, while scientists establish if the new variant is more transmissible and results in more serious illness, and how susceptible it is to current vaccines. British Prime Minister Boris Johnson said the travel restrictions are necessary to prevent as much entry of Omicron as possible into the UK and to delay outbreaks of the new variant so …