Delta variant challenges China's zero Covid strategy — and raises questions over its vaccine efficacy

China's hardline zero Covid strategy is facing a fresh challenge from the rapid spreadof the Delta variant, amid concerns over the efficacy of Chinese vaccines against the highly contagious strain. The Delta variant, which appears to cause more severe illness and spreads as easily as chickenpox according to an internal document from the US Centers for Disease Control and Prevention (CDC), has wreaked havoc across the world. Now, it is causing China's worst outbreak in months.

China reported 328 local Covid-19 infections in July, close to the total from the previous five months, according to the National Health Commission. Although that's only a fraction of the cases reported in countries like the United States and the United Kingdom, it is perceived as a serious threat in China, where authorities attempt to keep local infections at zero.

The latest outbreak started two weeks ago in the eastern city of Nanjing, where nine airport cleaners were found to be infected during a routine test. Since then, the cluster has spread to at least 26 cities across China, including a tourist hot spot in the southern province of Hunan and the capital Beijing.
Chinese authorities responded swiftly with mass testing, targeted lockdowns, extensive contact tracing and quarantine of close contacts — a tried and tested formula that has helped it quickly tame local flare-ups since March 2020.

Read more