(Bloomberg) -- Fewer Hong Kong residents are showing up to get vaccines from Chinese maker Sinovac Biotech Ltd. amid reports of side effects, even as demand was strong for shots developed by BioNTech SE-Pfizer Inc. on the day of their debut.

The number of people who received their scheduled Sinovac immunizations at community vaccination centers fell to 72% on Wednesday, down from a high of more than 90% last week. More than one-third of those who signed up for the vaccine, 36%, were no-shows on Tuesday.

The BioNTech vaccine, brought into the city by Shanghai Fosun Pharmaceutical Co., was administered to 91% of those signed up to get it on Wednesday, the first day it was available.

The skipping of Sinovac vaccine appointments comes after the city reported three deaths and three critical illnesses among the more than 130,000 people inoculated to date. While none have been linked to the Sinovac vaccines, hesitancy around getting the shots has risen among residents. Authorities preliminarily ruled out a tie between the vaccines and the first two deaths and two critical cases, while they are still analyzing the more recent reports.

“It’s understandable some residents are worried about the latest serious adverse events and even deaths following vaccination,” Secretary for the Civil Service Patrick Nip said on Tuesday. All of the serious side effects will be reviewed closely by an expert committee, as is common procedure, he said.

India and mainland China also had sluggish starts to their vaccination efforts, due at least in part to distrust and concern over the recently-released Covid-19 vaccines.

Hong Kong began its public vaccination campaign on Feb. 26, prioritizing people aged 60 and older, health-care staff and other essential workers. Starting Tuesday, it expanded its priority groups to cover 3.7 million people, about half of its population, adding those in high-risk contact positions like teachers, public transportation drivers and restaurant workers.

Other countries also have reported fatalities among people who have received inoculations, though the numbers have been small and nearly all cases involved underlying conditions. None of the deaths or serious complications have been tied to the shots.

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