BioNTech vaccine more effective as booster jab, says health expert

A health expert said on Thursday that the BioNTech vaccine is preferable to the Sinovac vaccine as a booster jab, as it offers more protection against the Delta variant.

Speaking on a radio program, Professor Ivan Hung Fan-ngai, co-convenor of the government panel on vaccine effects, said the BioNTech vaccine offers more protection against the Delta variant of the coronavirus when compared to the Sinovac vaccine.

“It does not mean the Sinovac vaccine itself is not effective. Given Sinovac is an inactivated vaccine, its effectiveness relies on the inactivated virus it uses during vaccine development.

“The inactivated virus inside the Sinovac vaccine are those discovered early in the Covid pandemic. If we need the booster dose to be effective, the inactivated virus must be the newer variants of the coronavirus -- like the Delta variant,” said Hung.

Meanwhile, the health expert said a “mixed dose” study by HKU has promising results, with findings showing that the mixing of the BioNTech and Sinovac Covid-19 vaccines appears to be safe and gives good protection against the coronavirus.

Hung said the study showed that the approach is generally safe and effective, but researchers are still waiting for the results of antibody tests from some of the test subjects.

He said the university has also just begun research on the effect of a third Covid jab for people with compromised immune systems, including those who had undergone organ transplants and cancer patients on chemotherapy.

“All test subjects will receive the BioNTech vaccine as a booster dose, with half of them getting the vaccine through intramuscular injection, and the other half getting it through intradermal injection,” said Hung.

He said the reason for having two different ways of injection is to help researchers understand whether it will affect the antibody levels generated inside the human body.

The health expert also pointed out that around half of the test subjects have a very low antibody level against the coronavirus, six months after they have received their second jab.

He believed that it is only a matter of time for people to get a third jab, regardless of whether they received Sinovac or BioNTech jabs.

He also said the government should first turn its focus on encouraging the elderly in Hong Kong to get vaccinated.
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