In an interview with the China News Service, he said this would help meet the requirements needed to reopen the border with the mainland.
He explained that as the incubation period of the more infectious Delta variant is four-and-a-half days, a seven-day quarantine could cut its transmission.
Professor Hui said the possibility of a community outbreak is not high, after two pilots infected with Covid-19, who were exempted from quarantine, entered the community. But he warned that Hong Kong might not be so lucky every time.
He added that even though most infected flight crew members may show mild or even no symptoms after vaccination, they could still spread the coronavirus.