The patient, a 35-year-old police constable, appeared to have snapped the city’s 38-day streak without an untraceable infection. However, this latest development will mean Hong Kong has now gone 40 days without an untraceable case.
The Centre for Health Protection (CHP) said the discovery of the mix-up was made following genetic analyses done by the Department of Health and the University of Hong Kong.
“After examining the clinical, epidemiological and laboratory findings, this case is compatible with vaccine strain contamination and hence will not be classified as a case of Covid-19 infection and has been deleted,” officials said.
“The exact source of the contamination will require further investigation.”
Authorities added that the man’s close contacts will be released from quarantine if they obtain a negative test result.
The CHP earlier revealed that the policeman had planned to get a Sinovac jab at a vaccination centre at the Central Library last Friday, but was turned away because he had symptoms of an upper respiratory tract infection.
While he initially tested positive for the virus, his subsequent test results came back negative, and he was not found to have any antibodies.
Health officials and infectious disease expert Yuen Kwok-yung on Wednesday visited the vaccination centre, as well as other places the man went, to investigate where he may have picked up the virus.
In late May, a nurse who helped to administer Sinovac jabs at the Kwun Chung Sports Centre in Jordan also tested positive for coronavirus, but the virus found in her was later found to be the same as the inactivated one contained in the vaccine.
Officials reported only one new imported case on Wednesday, involving a 58-year-old man from the United Arab Emirates.
He was asymptomatic and stayed at the MetroPark Hotel Kowloon in Ho Man Tin.
Since the beginning of the pandemic, Hong Kong has recorded 11,848 confirmed cases and 210 related deaths.