One of the patients bought a hamster from the Little Boss store in Causeway Bay which has already been linked to other Covid cases, with another customer and a member of staff earlier coming down with the disease.
The other new patient made purchases early this month at the I Love Rabbit pet shop in Mong Kok, which also had hamsters for sale.
A sample collected from a hamster cage at another I Love Rabbit branch, in Yuen Long, also came back positive, the authorities said.
Meanwhile, officials have found that genome sequencing for the Delta strain of Covid caught by the Little Boss shop worker is different to that of the first customer who tested positive.
“At this point, it is possible that [the staff] did not directly transmit the illness to the customer. It is possible that the customer stayed in the environment where there was animals, or she has a hamster at home. So we don’t know which is the exact source of infection, but it is possible that animal to human transmission did occur,” said Dr Chuang Shuk-kwan from the Centre for Health Protection.
Genome sequencing has also found that a 17-year-old student who has the Delta variant is not linked to the Little Boss pet shop cluster. The authorities said they were still trying to trace the source of his infection.
Other new untraceable suspected infections include a social work assistant who works in Kwai Chung and lives in Cheung Sha Wan and a woman who works in Kwun Tong and lives in Tsuen Wan.
Officials also announced an 82-year-old man living in Aberdeen as an unlinked preliminary positive case, but they said he frequently ate at a restaurant where an earlier Covid patient had lunch and there might be a connection between the two infections.