Cities in the region may be off to a slow start in their inoculation drive due to the lack of Covid-19 vaccine stocks, but it is the reverse in Hong Kong - there are ample supplies but not many willing takers.

Hong Kongers "only have a three-month window" before the city's first batch of Pfizer-BioNTech doses reaches its expiry date, a member of the government's vaccine task force warned yesterday.

Urging residents to book an appointment now, Mr Thomas Tsang warned that Hong Kong may not be able to get its hands on more doses for the rest of the year.

Mr Tsang, a former controller of the Centre for Health Protection, drove home the point while speaking on public broadcaster RTHK's Hong Kong Today programme.

He noted that Hong Kong has been fortunate to be able to secure vaccines for the entire 7.5 million population but the take-up rate was only around 20 per cent.

The "unsatisfactory" take-up rate for both the Chinese Sinovac and German-made Pfizer-BioNTech vaccines has left officials, who are counting on vaccination to reopen the economy, with a headache.

The free and voluntary vaccination programme that started in late February is open to those aged 16 and above, and more than 2.2 million doses have been administered.

About 1.3 million individuals have received their first dose, with 55 per cent of them choosing the Pfizer vaccine. Sinovac has yet to be approved by the World Health Organisation but was fast-tracked for use by city health regulators.

Mr Tsang attributed the low vaccination rate to a false perception that the vaccines are not safe.

Discouraging a wait-and-see approach, he said: "The whole world is scrambling for vaccines... What we have is probably all we have for the rest of the year."

Experts have said that vaccine hesitancy in the community is likely to stay, especially as the city's pandemic situation comes under control.

They noted that news reports of adverse reactions to the jabs have planted misgivings about vaccine safety that are now hard to change. This is perpetuated by the lack of trust in the government.

As at May 16, reports of adverse events including migraine, chest pain and facial paralysis were reported in 0.15 per cent or about 2,890 cases of the two million doses administered in the city.

There were reports of 20 deaths within 14 days of vaccination - that is 0.001 per cent fatality for all doses given.

Hong Kong appears to have brought its fourth wave of infections under control. The city has recorded more than 11,800 confirmed infections and 210 deaths, with local cases down to between one and three in the past 28 days.

Officials have in recent weeks encouraged residents to get vaccinated, stressing that community vaccination centres for the Pfizer shot will cease operations after September, when the jabs expire.

"So we only have maybe a three-month window to get vaccinated if you are considering BioNTech. After that, it may be much more difficult," Mr Tsang said.

Hong Kong has secured 7.5 million doses each of the Sinovac and Pfizer-BioNTech vaccines.

Speaking ahead of the weekly executive council meeting, Chief Executive Carrie Lam yesterday said that the government hopes employers in the private sector can provide incentives to encourage staff to get vaccinated.

Likewise, the government will incentivise people through policies, such as relaxing social distancing rules in step with the vaccination rate.

The government is also hoping to ease the aggressive testing of staff from various sectors, including healthcare and the civil service, as the vaccination rate goes up.

"At the moment, they are required to undergo testing every 14 days, but they may be exempted if they have been fully inoculated," Mrs Lam said, adding that the government is also considering giving civil servants who have taken their jabs days off.

Separately, the government said yesterday that the vaccination programme will be extended from Friday to include the group of about 40,000 mainland residents who hold a permit to travel to and from Hong Kong and Macau and whose stay in Hong Kong has been extended due to the pandemic.