A US consulate employee in Hong Kong who tested positive for Covid-19 for the second time after a previous infection six months ago was unlikely to have contracted the virus recently, health authorities said.
The news came a day after the 25-year-old woman’s preliminary result triggered the closure of Washington’s offices in the city.
There was only one imported coronavirus case on Tuesday, with a 56-year-old aircrew member from Russia the city’s lone infection.
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The US consulate employee, who came to Hong Kong in March, had been infected six months ago and is classified as an overseas case.
According to health officials, the specimen collected from the asymptomatic consulate staff member on Sunday tested positive, she then tested negative upon admission to hospital, but positive for the antibody.
“Initial investigations of the Centre for Health Protection revealed that the patient had been diagnosed with Covid-19 in the United States in January this year,” a statement read. “After examining the epidemiological, clinical and laboratory findings, this case is compatible with a re-positive case.”
Authorities said the woman had not been vaccinated, and added that officials were following up with US health authorities in an ongoing investigation.
Her case had not been included in the city’s tally of infections, with the confirmed number standing at 11,944, with 212 related deaths.
The staff member’s positive test triggered the closure of the US consulate building in Central on Tuesday for deep cleaning and disinfection. All scheduled services and visa applications on Tuesday had also been cancelled.
The consulate said the employee in question “does not work in an office that interacts with the public”.
There have been incidents of recovered Covid-19 patients testing positive after being discharged from hospital, both in Hong Kong and overseas, though those people might no longer be infectious.