Questions had been raised over how the 38-year-old woman was able to benefit from reduced quarantine for people who test positive for Covid antibodies. She left for the United States before the scheme was introduced on June 30 and only tests carried out at laboratories in Hong Kong count.
The Food and Health Bureau confirmed to RTHK on Sunday that the woman, who was fully vaccinated with the BioNTech jab, sent a blood sample from the United States to be processed by a laboratory in Hong Kong, allowing her to produce the test certificate on her return on August 1.
The bureau said it had reminded laboratories not to accept samples taken abroad. It said it did not rule out taking further action.
The woman, who works as a domestic helper, was confirmed to be infected with the more contagious L452R mutant strain on Saturday, having initially tested negative before and after her flight back to the SAR. She had no symptoms.
She visited several places in Wan Chai and Causeway Bay, as well as near her home in Stanley, and used public transport to get there. The family she works for are being treated as close contacts.
The diagnosis prompted calls from infectious disease experts for a rethink of the reduced quarantine scheme, or for the United States to be added to a list of high-risk countries that are not covered by it.
An expert committee under the Centre for Health Protection will meet to consider the matter on Monday.