Liang had received three domestically developed vaccine doses from China's Sinovac over the past two years, but said she took Pfizer-BioNTech's Comirnaty bivalent booster shot on Thursday to better protect herself against the virus.

The hospital is expecting more people like Liang to come to Hong Kong from the mainland to get their COVID mRNA vaccine shots, chief medical executive Samuel Kwok told reporters at the media event.

China, home to 1.4 billion people, abruptly abandoned its "zero-COVID" policy last month and infections are surging across a population with little immunity after being shielded since the virus emerged three years ago in the Chinese city of Wuhan.