In China, public health officials warn COVID-19 cases are spreading rapidly and show no sign of slowing down, after officials in Beijing abandoned their long-standing “zero COVID” policy. Researchers estimate some 800 million people in China — or about one-tenth of humanity — could become infected by the coronavirus over the next 90 days. Several models predict more than a half-million people could die. China’s population remains especially vulnerable to a winter surge because few people have been exposed to the coronavirus. There are also concerns about the effectiveness of China’s domestically produced vaccines, which rely on inactivated forms of the virus. It’s a technology that’s proven to be less protective than the mRNA vaccines widely used elsewhere.