Hong Kong will extend a digital vaccination pass that controls which premises residents can enter to children as young as five years old, authorities announced Thursday. The new rules mean any child above the age of five will need to produce a proof of vaccination QR code to enter restaurants, swimming pools, libraries, and other venues. Hong Kong adheres to a looser version of China’s zero-Covid policy, under which infections are quashed with stringent border controls, lockdowns and social-distancing measures. It also deploys a “Leave Home Safe” app to store vaccination records and monitor movements. Those wishing to enter most...