After scientists in South Africa found a new variant of Covid-19, the country reported a rise in infections with the positivity rate jumping from the seven-day average of 4.3% to 9.1% on Friday evening, health authorities said. "About 2,828 new COVID-19 cases have been identified in South Africa, which brings the total number of laboratory-confirmed cases to nearly 3 million. This increase represents a 9.1% positivity rate," the National Institute ...