China's Delta outbreak tests limits of zero-tolerance Covid approach

The rise of the highly-contagious Delta variant is challenging even the most aggressive Covid-19 containment regimes, an ominous sign as economies look to open up and return to pre-pandemic life.

An outbreak that started at an airport in the eastern Chinese city of Nanjing is testing that country’s zero-tolerance measures, which are some of the most sweeping and comprehensive in the world. New infections are rising by the dozens and seeding subsequent clusters around China despite well-honed systems of mass testing and stringent quarantines. Beijing reported its first locally-transmitted infection in six months Thursday, linked to an outbreak in the southern province of Hunan among people who’d recently been to Nanjing.

The variant is scaling some of the toughest virus defenses, with “Covid Zero” places —countries that had snuffed out the virus within their borders — still seeing outbreaks despite strict anti-virus measures.

In China, the first infections were among nine airport cleaners. The cluster quickly expanded to their close contacts, then to a handful of other locations, leading to nearly 200 confirmed Covid cases as of Thursday. It’s one of China’s biggest outbreaks since a wave concentrated in the country’s northeast saw more than 2,000 infections last winter.

Officials have confirmed that the new outbreak is caused by the Delta strain, which has been driving a resurgence in infections across the world.

Alternative proposal for virus origin probe

China says it’s put forward alternative parameters for a second probe into the origins of Covid-19 that should span multiple countries, Beijing’s latest move to counter a push by the US for a deeper investigation into the theory the virus leaked from a Wuhan lab.