The world still lacks a proven coronavirus vaccine, but that has not stopped Chinese officials from trying to inoculate tens of thousands, if not hundreds of thousands, of people outside the traditional testing process. Three vaccine candidates are being injected into workers whom the government considers essential, along with many others, including employees of the pharmaceutical firms themselves.

As the world moves toward another morbid threshold in the pandemic, a coronavirus death toll of one million, the countries where fatalities are increasing fastest remain spread out across the globe, with new hot spots constantly emerging.

The number of lives lost daily to the virus has been rising through most of August and September, reaching more than 5,000 in an average measured over seven days. As of Sunday morning, the global total stood at 993,600, according to a New York Times database.

Why the coronavirus affects children much less severely than adults has become an enduring mystery of the pandemic. The vast majority of children do not get sick; when they do, they usually recover.