COVID-19 cases are rising again in South Africa in what public health officials worry could be a sign of things to come in other nations, including the United States. South Africa’s fifth coronavirus wave is being fueled by the BA.4 and BA.5 subvariants of the Omicron variant, which swept the world after it was first detected in southern Africa last November. The latest variants have mutations that appear to help them evade people’s immune responses to other variants, including earlier forms of Omicron.

In China, authorities reported 58 new coronavirus cases in Shanghai outside of areas of the city under strict lockdown. It’s the latest blow to China’s “zero-COVID” strategy and comes after Beijing canceled celebrations and public gatherings around the May Day holiday in order to press ahead with mass testing for millions of residents of China’s capital city.