The 35-year-old officer was declared the first local case with no clear source in more than a month on Tuesday, but has now been removed from the tally.
After an investigation, the University of Hong Kong’s Yuen said the virus found in the man’s sample was the same as the inactivated version contained in the Sinovac vaccine.
He said the Lok Fu clinic the police officer visited to collect his test kit had administered Sinovac jabs to four people the same morning, and a nurse had removed labels from the vaccine bottles to stick them on the patients’ records after inoculation.
“The same nurse may be the one who actually dispensed the deep throat saliva collection package to the police officer,” said Yuen, a government adviser on the pandemic.
“During the process, it’s highly possible that her fingers have been contaminated with the residual vaccine and then introduced it inside the collection package, and this leads to the contamination of the deep throat saliva sample from the police officer.”
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.
But Yuen said it’s unlikely that the vaccination centre is the source of contamination, as the man never went near the vaccination booths.
The University of Hong Kong expert urged medics in private clinics to wear gloves when vaccinating people, and to wash their hands after the gloves are removed.
He said there should also be clear divisions of labour to prevent similar contamination from happening again, such as having different staff handle vaccine bottles and test kits.
Clinics should also be cleaned with bleach every day, he added.