Professor David Hui Shu-cheong, chairman of the Scientific Committee on Emerging and Zoonotic Diseases, said the meeting had looked into the use of XBB mRNA vaccines made by US drug firms Pfizer and Moderna.

He said that if the supply of the XBB vaccine was limited, priority should be given to high-risk groups such as elderly residents in care homes.

More than 98 per cent of the city’s current Covid-19 cases involved XBB.

The joint scientific committees described the XBB vaccines as offering “safe, modestly enhanced protection” against circulating and recently emerging variants.

Data reviewed by the experts showed that the two XBB vaccines could protect against XBB, as well as the EG.5 and BA.2.86 variants, which were becoming more prevalent.

Hui said the meeting did not discuss the XBB vaccine made by US biotechnology company Novavax and approved by the United States’ Federal Drug Administration early this month as the experts did not receive data for review.

Experts warned the Covid-19 activity level in Hong Kong was very likely to be higher during winter.

“The Covid-19 activity level is still stable. But there could be another surge during winter, and hopefully it will not be that serious,” said Dr Chuang Shuk-kwan, head of the centre’s communicable disease branch.

Earlier this week, Hui said the Covid-19 positive rate using nucleic acid testing was 15 per cent based on Hospital Authority data and that there were about 100 to 120 hospitalisations per day.

The authority said that as of Tuesday, 700 public hospital patients were infected with Covid-19, with around 30 in severe or critical condition.

03:16

Nobel Medicine Prize given to 2 scientists for mRNA research that enabled Covid vaccine

Nobel Medicine Prize given to 2 scientists for mRNA research that enabled Covid vaccine

The experts also recommended that the high-risk groups, including people aged 18 to 49 with chronic diseases and immunocompromised children aged at least six months, take a Covid-19 booster dose if more than six months had passed since their last vaccination or infection.

“They do not have to wait for the third-generation XBB vaccines and can still use the currently available jabs,” said Hui, adding that the existing shots were still very effective in reducing severe cases and deaths.

Chuang said the government would initiate procurement procedures for the XBB vaccines. But further details including when the vaccines would be available would be known only after they had been procured.

Government subsidised vaccination programmes include first-generation monovalent vaccines produced by Pfizer and Sinovac, as well as the US firm’s second-generation shots, which are based on the original virus strain and the Omicron variant.

Professor Lau Yu-lung, chairman of the Scientific Committee on Vaccine Preventable Diseases, also urged the public, especially those at high risk, to get flu shots, which could be administered at the same time as the Covid-19 jab.

Lau said the latest surveillance data showed more children aged five years or younger were being hospitalised because of the flu rather than Covid-19.

“Flu, in fact, in my mind, is even more urgent than Covid in terms of vaccination,” Lau said.

Hong Kong has been hit by an ongoing summer flu peak since late August, and another surge of infections is expected during the winter.

Lau said more than 200 serious flu cases had been reported, including over 120 deaths, in the current summer flu season. Most of those who died were elderly.