He made the comment after Chief Executive Carrie Lam on Tuesday announced plans to carry out three rounds of mandatory Covid-19 testing on the entire population next month.
Leung, the dean of the University of Hong Kong’s faculty of medicine, said their analysis suggests that the current fifth wave will peak in the first or second week of March, before gradually fading out in late April.
He said the best timing for Hong Kong to carry out citywide testing will be when the epidemic is in its “natural fade-out stage”.
“If you then do universal testing, and you have sufficient isolation facilities to support it, you could then hasten that fade-out than it otherwise would naturally do so,” he said.
“If you have sufficient isolation facilities and you then identify, rather quickly with two or three consecutive tests, all of the positive infected people in the community, and isolate them so that they do not go on to infect others, then you can hasten that fade-out.”
“But it would be on the downward slope of that epidemic curve, it would not be during the exponential growth phase. Because during the exponential growth phase, one, we don’t have the isolation facilities, two, it would not be a useful exercise because it’s still growing and you’re not able to turn that trajectory,” he added.
Leung, who has been advising the government on the pandemic, also stressed the importance for children to get vaccinated during what he called a “window period” between now and Easter, before students resume face-to-face classes after an early “summer break”.
He said a high vaccination rate among schoolchildren could also help prevent yet another wave of infections when face-to-face classes resume – something he said many overseas places have seen.
“In many of those countries, when classes resume, in school-age children, you see another mini-wave as the children congregate in the school-setting. And that’s why it’s so important between now and the end of April, if the plan is to go ahead with in-person classes then, to vaccinate as many children as possible,” he said.
The expert also said the government should consider lifting the ban on flights from nine countries, including the United States and the United Kingdom, which has been extended until April 20.
He said since the risk of imported infections is not any higher than that of local transmission, there is no reason not to allow Hongkongers stranded abroad to come home.