The first Covid-19 vaccines due to arrive from the mainland as early as next month should be safe to use despite a lack of final clinical results, experts said in trying to reassure people about receiving the jabs.
The vaccine produced by mainland pharmaceutical firm Sinovac uses an inactivated virus like - a system used in flu jabs for years, University of Hong Kong infectious disease expert Ho Pak-leung said.
The company is also a leader in its field, Ho said, although there have yet to be statistics released on the Covid-19 vaccine's effectiveness and safety.
"I believe Sinovac phase 3 clinical trial data will be out soon," Ho said.
"Citizens should not just look at available data at this moment. We should also look into the future."
With one million Sinovac jabs expected to arrive in January, Ho called for authorities to recruit 10,000 medics to administer all the shots within 10 days. The makers of two other vaccines being purchased by the SAR have already published some of the results of their stage 3 clinical trials.
The one developed by German pharmaceutical firm BioNTech and produced by Pfizer is expected to arrive in Hong Kong in the first quarter of 2001.
It comes with a new technology to trick the body into making the viral protein and eventually triggering an immune response.
It has already been approved by five countries including Britain, Canada and the United States after trials proved it to be 95 percent effective. "Every day there are up to millions of people receiving this vaccine," Ho said. "In several weeks we'll have a very large sample size and scientific data on the shots."
The other vaccine, which is one developed in Britain by AstraZeneca and the University of Oxford, has proven 62 to 90 percent effective and should be available in Hong Kong in mid-2021. It uses a technology involving an engineered Covid-19 virus.
Despite the BioNTech shots having the highest effectiveness so far, transportation and storage of the jabs will be a challenge. The vaccine must be kept in temperatures of minus-70 degrees Celsius.
The other two vaccines can be stored between two to eight degrees Celsius.
Ho said people should make a decision based on science and not politics on whether to get vaccinated.
That came with the Food and Health Bureau releasing a statement to dismiss online rumors that the procurement of Covid-19 vaccines was based on political considerations to benefit mainland companies.
A bureau spokesman said the accusations were "entirely made up" and the SAR administration only considered candidate vaccines' effectiveness and safety.
Government adviser David Hui Shu-cheong of the Chinese University of Hong Kong said he would only be able to decide which vaccine is the most desirable one after looking at all clinical trial data.
He also noted that people have to be injected with the same type of Covid-19 vaccine twice in order to develop immunity, but it may not be necessary for them to get the jab every year.
People should be given the choice on whether to get vaccinated based on the protection and potential side effects, Hui said.
Another government expert adviser, Yuen Kwok-yung, said people should not worry about mainland-made vaccines.
"I believe in Chinese vaccine companies," the microbiologist said. "The state's food and drug administration is very cautious in approving vaccines. I trust the shots will be of good quality."
But he said he would wait for his HKU team to develop a nasal spray vaccine, which is being manufactured in Changchun. "I'll save my quota to try out our own vaccine," he said.
Around 100 volunteers are being recruited for the nasal spray vaccine's Phase 1 clinical trial, which is expected to be completed in two to three months.
Then it is expected to be ready for use toward the end of 2021.