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The research, led by Dr Malik Peiris and Dr David Hui, examined the production of virus-neutralising antibodies in the blood of people vaccinated with the two shots currently in use in Hong Kong.
They confirm two doses of either vaccine was not sufficient to fend off Omicron.
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3 Sinovac doses fail to protect against Omicron in study
BEIJING (BLOOMBERG) – Two doses and a booster of the Covid-19 vaccine made by China’s Sinovac Biotech, one of the most widely used in the world, did not produce sufficient levels of neutralising antibodies to protect against the Omicron variant, a laboratory study has found.
For those who are fully immunised with the vaccine known as CoronaVac, getting a booster shot from Germany’s BioNTech SE significantly improved protective levels of antibodies against Omicron, according to the study from the University of Hong Kong and The Chinese University of Hong Kong.
Two doses of the BioNTech shot, known as Comirnaty, was also insufficient, though adding a booster with the more potent mRNA vaccine raised protection to adequate levels, the researchers said in a statement.
The findings are in line with results disclosed by the vaccine-makers.
Last week, Sinovac released lab studies saying that 94 per cent of people getting three doses generated neutralising antibodies, though it did not say at what level.
The Hong Kong researchers set a threshold for what they considered a sufficient level of antibodies for protection based on earlier studies published in the journal Nature Medicine.
Sinovac officials did not immediately respond to calls seeking comment.
While much is still unknown about how Sinovac’s shot holds up to Omicron – including how T cells, the immune system’s weapon against virus-infected cells, will respond – the initial results are a blow to those who have received CoronaVac.
There have been more than 2.3 billion doses of the shot produced and shipped out, mostly in China and the developing world.
With Omicron seen to be about 70 times more transmissible than the Delta variant, the prospect of having to roll out a different booster shot or even re-vaccinate with a more Omicron-specific vaccine will set back the world’s efforts to exit the pandemic.
The research, led by Dr Malik Peiris and Dr David Hui, examined the production of virus-neutralising antibodies in the blood of people vaccinated with the two shots currently in use in Hong Kong.
They confirm two doses of either vaccine was not sufficient to fend off Omicron.
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Sinovac shot offers inadequate shield from Omicron variant, says HK study
Published 15 Dec 2021, 11:07 am SGT FacebookTwitter
HONG KONG (BLOOMBERG) – The vaccine made by Sinovac Biotech, one of the most widely used in the world, does not provide sufficient antibodies to neutralise the Omicron variant, said Hong Kong researchers in initial lab findings that may have sweeping consequences for the millions of people relying on the Chinese shot to protect them against Covid-19.
Among a group of 25 people fully vaccinated with the Sinovac shot, none showed sufficient antibodies in their blood serum to neutralise Omicron, said a statement from a team of researchers at the University of Hong Kong that was released late on Tuesday night (Dec 14).
In a separate group of 25 people fully vaccinated with the mRNA shot developed by Pfizer and BioNTech, five of them had neutralising ability against the new variant, the scientists said.
That was in line with findings released last week by the companies, which said a third shot would be sufficient to protect against Omicron.
Led by microbiologist Yuen Kwok Yung, a highly respected professor in infectious diseases at the University of Hong Kong, the study of 50 people has been accepted for publication in medical journal Clinical Infectious Diseases and is available online as a pre-print.
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The Hong Kong research team has exported the isolated Omicron virus to China’s government and vaccine manufacturers for the development of vaccines targeting the new variant, they said.
Sinovac Biotech said last week it was studying how its vaccine holds up against Omicron but gave no timeline for releasing results. The Beijing-based company did not immediately reply to requests for comment on the Hong Kong University findings.
The scientists also advised members of the public to get a third vaccine dose as soon as possible, while awaiting the next generation of shots.
But whether a third dose of the present Sinovac vaccine will improve the neutralising antibody response against the Omicron variant remains to be determined, they said.
Antibodies, which the researchers studied, are one important arm of the immune response protecting people from infection. The other arm of the immune response is cell-mediated immunity – known as T-cell response – which can protect people from serious illness and death.
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https://www.globaltimes.cn/page/202112/1241588.shtml
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