China has reported 5,280 COVID-19 cases for the first time since the early days of the pandemic, driven by 'stealth Omicron' variant, reports said. The 'stealth Omicron' - or the BA.2 sub-variant, is 1.5 times more transmissible than the original Omicron strain, studies suggest. At least 10 cities and counties were locked down including Shenzhen, home to 17 million people.