More tourism and culture venues as well as hospitals in Shanghai were shut down on Thursday after the city reported five new locally transmitted COVID-19 cases with mild symptoms and 21 local asymptomatic cases.Apart from an asymptomatic case who tested positive during screening, all the other cases returned positive tests after being centrally quarantined as close contacts of previous cases, Wu Jinglei, head of the Shanghai Health Commission, told a press briefing.The new cases, aged between 10 and 72 years, have been sent to the Shanghai Public Health Clinical Center for treatment or quarantined medical observation, he revealed.