HKU breakthrough in Omicron jab race

University of Hong Kong researchers will soon partner with a mainland drugmaker to develop a vaccine against Omicron after they successfully isolated samples of the fast-spreading variant.

Hong Kong yesterday recorded a fourth Omicron case - a man arriving from Nigeria on November 24. So far, none of the Omicron cases have entered the community.

HKU has become the first in Asia to successfully isolate Omicron, four days after the variant's first two cases were confirmed in the city and five days after it was reported by South Africa to the World Health Organization on November 24.

HKU microbiologist Yuen Kwok-yung said the partnership is aimed at producing a new generation of jabs that carry deactivated Omicron variants, but refused to disclose the name of the mainland firm as contracts have yet to be signed.

Yuen said existing vaccines - including the Beijing-made Sinovac and German-made BioNTech/Fosun available in Hong Kong -can still offer protection against Omicron infections.

He cited two cases in Hong Kong as an example, in which a South African man carrying the Omicron variant infected a Canadian staying in the opposite room at quarantine hotel Regal Airport.

Yuen said both men have received two BioNTech doses less than six months ago and only suffered mild symptoms.

"We have been doing blood tests for them. In just several days after diagnosis, their antibodies level rose tenfold, meaning mRNA vaccine [BioNTech] has made the immune system memorize the virus, triggering it to quickly produce antibodies," he said.

"This is a very good sign and once again points to the need that everybody should consider taking the vaccine as soon as possible."

Yuen said although the two patients stayed in opposite rooms, they never had physical contact or opened their doors at the same time.

"That means their transmission must be air-borne, which raises concerns that [Omicron] may be more transmissible than the Delta variant," he said.

But Yuen said more studies using the Omicron samples have to be conducted to evaluate whether the variant is actually more contagious or triggers more serious symptoms.

Polytechnic University's department of health technology and informatics assistant professor Gilman Siu Kit-hang said Omicron - with the highest number of mutations among all known variants at more than 30 - could have been transmitted from humans to animals, where the dramatic mutations took place, before it jumped back to humans.

But Yuen said it is also possible that the Omicron mutations occurred in AIDS patients.

"There are quite a number of AIDS patients in South Africa, who are immunocompromised and are unable to completely eradicate Covid-19 virus after they are infected," he said.

"Their bodies could have become a desirable atmosphere for mutation."

The Centre for Health Protection reported the city's fourth Omicron infection - a 38-year-old unvaccinated man, who on November 24 flew to Hong Kong on Qatar Airways flight QR818 from Nigeria via Qatar.

He was a transit passenger but was stranded in Hong Kong International Airport due to visa issues. On Saturday, he received a Covid test at the airport and became a confirmed case on Sunday.

He is in stable condition at the North Lantau Hospital Infection Control Centre.

Although the man had a low viral load, he had stayed at the restricted area of the transit hall for four days before testing positive. It is understood around 20 airport staff have been classified as close contacts and will quarantine for 21 days at Penny's Bay.

So far, two of Hong Kong's Omicron cases came from South Africa and two from Nigeria.

Meanwhile, the center reported three imported cases from Pakistan, Spain and the Philippines yesterday. One of them carried the L452R mutant strain likely to be the Delta variant.

Genetic sequencing of the two others are pending.

jane.cheung@singtaonewscorp.com