HONG KONG (BLOOMBERG) - Hong Kong saw a jump in bookings for coronavirus vaccine appointments after eligibility was widened to all residents aged 16 and older, as the city works to boost inoculation rates seen as crucial to achieving herd immunity.

About 25,200 people reserved slots for BioNTech vaccinations at community centers in the 24 hours to 8pm Friday (April 23), while another 6,100 booked appointments to receive shots made by China's Sinovac Biotech, the government said.

Total bookings, which include first and second doses, more than doubled from 14,700 a day earlier. The figures don't include private clinics, which offer Sinovac jabs.

The expansion, announced earlier this month, means that all Hong Kong adults will now be able to access vaccines, amid a rollout effort that has been hampered in part by distrust in the local government and questions about the efficacy of Chinese vaccines. Hong Kong is one of the first places globally to roll out vaccinations to its full adult population.

About 409,400 people received the first dose of the BioNTech vaccine as at Friday, surpassing those for Sinovac. The BioNTech programme was temporarily halted last month when packaging defects were found in some vials.

Still, only about 10.7 per cent of the Hong Kong population has received at least one dose of a vaccine, according to Bloomberg's Covid-19 Vaccine Tracker - less than half the rate of inoculation in rival finance hub Singapore. The low rate is slowing the city's effort to reach herd immunity, pivotal to a full reopening of the economy.

Hong Kong has secured an adequate supply of vaccines for its whole population - and should be in an "enviable position" as one of the first regions to reach herd immunity, Professor Lau Yu Lung, a member of the government advisory panel on Covid-19 vaccines, wrote this month in a local medical journal.

"Instead, we remain far from this goal because of vaccine hesitancy, internal conflict, and mistrust," Prof Lau wrote.

A government scientific committee said on Thursday that there was no need to introduce vaccines from AstraZeneca in Hong Kong, in part because of the availability of alternate vaccines.

Hong Kong has been ramping up efforts to incentivise sceptical residents to get vaccinated. The government this month outlined "vaccine bubbles" that would relax some social curbs only for vaccinated people. Chief Executive Carrie Lam said the new measures could be introduced toward the end of the month if the situation remained stable.

Bars and nightclubs will be conditionally allowed to reopen at half-capacity till 2am if all staff and customers receive at least one vaccine dose, according to Mr Tommy Cheung, a member of the advisory Executive Council, citing government officials. Two people are capped per table and rules will be reviewed every two weeks, he said Friday.

The latest expansion of eligibility also comes as the city wrestles with a highly transmissible virus variant that triggered a 14-day ban on flights from India, Pakistan and the Philippines.