Last week, officials said the 27-year-old airport worker had become the city’s first patient with the more infectious variant. His housing block in Tai Po was locked down as officials rushed to test residents there.
The Centre for Health Protection (CHP) said last Friday that genetic sequencing had found identical genomes in the 27-year-old and three previously reported imported cases, all involving the L452R mutant strain that is present in a number of variants, including Delta.
It said on Tuesday that its investigation had also revealed that these people had brief encounters at a specimen collection centre at the airport on June 11.
The 27-year-old also worked part-time as a customer services assistant in Tai Po’s Uptown Plaza, and a colleague of his there, a 24-year-old woman, was confirmed to be infected with Covid-19 on Sunday.
Fears of a community spread of the Delta variant also prompted a lockdown of her residence, and compulsory testing orders for her workplace.
The woman has also now been reclassified as an infection linked to an imported case.
Health officials reported one new imported case on Tuesday, involving a 43-year-old man who flew in from the United Kingdom. He was asymptomatic.