When Hong Kong Chief Executive Carrie Lam rolled up her shirt sleeve to get the Asian financial hub’s first COVID-19 vaccination last month, she gave a ringing endorsement of the shots produced by mainland Chinese firm Sinovac Biotech Ltd.

"We are taking the Sinovac vaccine today, which was developed and manufactured in the mainland, because this is the first vaccine that has arrived in Hong Kong,” Lam said on Feb. 22 as she got inoculated in a public ceremony with her top aides.

Since then, confidence in both Sinovac and her government’s vaccine drive has plummeted. Seven deaths and dozens of adverse reactions were reported following the first 160,000 doses of the shot, and residents began signing up in droves for the vaccine made by BioNTech SE and Pfizer Inc. — the only other one available.