The CHP said results showed that the trio are very likely to be infected during their stay in a hotel in Frankfurt.
Health authorities also said about a dozen environmental samples collected on a floor of a hotel in Tung Chung where two Covid patients had stayed came back positive.
The two patients, who were in quarantine in Four Points by Sheraton Hong Kong, Tung Chung, were earlier found to carry the more infectious AY.4.2 variant, dubbed “Delta plus”.
Officials said of the 73 environmental samples collected last week from their rooms and other common areas, 13 of those taken from the rooms tested positive for Covid-19.
The CHP said 44 hotel guests who had stayed on the same floor from November 1 to 6 were transferred to the Penny’s Bay quarantine centre. It also said disinfection in the hotel has been completed.
Meanwhile, health officials on Tuesday reported one new imported Covid infection involving a woman flying in from India.
The 21-year-old woman, who was fully vaccinated and asymptomatic, tested positive for the virus upon her arrival at the airport on Sunday.
She was found to be carrying the L452R mutant strain.