Health experts have suggested selling millions of Hong Kong's unused Covid-19 vaccines or pausing the phased supply from manufacturers to minimise waste, as the government explores donating the shots while racing against looming expiry dates. Nearly 4 million jabs from Chinese producer Sinovac and Germany's BioNTech have arrived in the city since February, but about 2 million of them are still languishing in storage amid a sluggish inoculation...