HONG KONG (BLOOMBERG) - Hong Kong government health advisers say there is no urgency to give residents Covid-19 booster shots since there have been no outbreaks in three months, a decision that runs counter to the steps many other developed economies are taking.
A third dose will not be needed until two to three months before the city's borders open, said experts on two panels convened by the Centre for Health Protection to study the issue.
Hong Kong's zero tolerance for any local Covid-19 infections means the virus is not circulating in the city now, reducing the need for extra protection, said Mr David Hui, chairman of the Scientific Committee on Emerging and Zoonotic Diseases.
The recommendation comes as research being conducted across the world suggests that the efficacy of coronavirus vaccines wanes over time. Pfizer submitted data to US regulators showing that infections break through the shots it developed with BioNTech faster in people who were vaccinated earlier, while boosters safely prevent transmission and new variants.
The technology accounts for nearly two-thirds of the immunisations given in Hong Kong.
In the financial hub, where natural immunity from previous infections is rare, declining protection from immunisations will leave more of the population vulnerable and in need of boosters before the city reopens its borders.
Thus far, Hong Kong's leaders have not given any indication as to when that will be, with no plans yet in place to ease some of the strictest travel curbs in the world - including quarantines that can last for as long as three weeks.
Israel has administered millions of booster shots and is making preparations in case a fourth round is needed. The United States and Britain, meanwhile, plan to start offering them later this month, while Europe is also considering third doses. China has approved the use of boosters for high-risk residents.
The experts also said adolescents aged 12 to 17 should get only one dose of the Pfizer-BioNTech vaccine due to the risk of myocarditis and the low threat of Covid-19 in Hong Kong. Sinovac's vaccine, the only other shot available in the city, has not been approved for those under the age of 18.
The approval of booster shots in wealthier nations has sparked controversy globally, as vast populations in the developing world are still waiting for their initial vaccinations.
The World Health Organisation has pleaded for a moratorium on third doses, with director-general Tedros Adhanom Ghebreyesus saying this month that governments should wait at least until the end of this year to allow poorer countries more access to vaccines.
An all-star panel of global scientists this week concluded that vaccines work so well that most people do not yet need boosters, a view likely to continue the debate over whether these should be broadly administered.
Hong Kong's vaccine effort, meanwhile, is hitting a wall. A large swathe of the population is refusing to get even one, fuelled in part by hesitancy among elderly citizens.
Since the campaign began in February, just 58 per cent of residents have been vaccinated with an initial dose, according to Bloomberg's Vaccine Tracker, compared with 81 per cent for rival financial hub Singapore. The city's appointment booking rate fell to a record low on Sunday.
Hong Kong has reported just two unlinked local cases in the past three months. Neither sparked further transmission. The authorities have vowed to stick to a Covid-19-zero strategy even as other places that have managed to keep infection rates low - including Singapore - move toward a post-pandemic future with fewer safety restrictions.
The city's quarantine measures remain some of the toughest in the world, and have fuelled concerns that it could be left behind as others reopen their borders.