The Indian man tested negative for the virus before he was released from a 21-day quarantine but he subsequently became infectious after he entered the community, leading to a cluster of variant cases in Hong Kong.
Dr Gilman Siu from Polytechnic University’s department of health technology and informatics said latest genetic analysis done by his team shows the man was infected by another man from the Philippines who stayed in a room next to him at the Ramada Hotel in Tsim Sha Tsui.
He said the virus carried by the man from the Philippines was the “ancestor” of the transmission chain of the Covid variant in Hong Kong.
“We compared the viral genome of these two cases. We found that one mutation is missing in [the virus carried by] the Filipino young man, suggesting this virus should be the ‘ancestor’. When it’s transmitted to the Indian man, it developed one more mutation,” he said.
He warned that mutated strains of the coronavirus might again be leaked into the community as the number of infections abroad rises.
He urged the government to limit the number of returnees to Hong Kong to prevent overcrowding and minimise the chance of virus transmission at quarantine hotels.