Omicron coronavirus variant could greatly reduce efficacy of HK vaccines, top scientist says

02-Dec-2021 Intellasia | South China Morning Post | 5:02 AM Print This Post

A leading microbiologist has warned that the Omicron coronavirus variant could significantly reduce the efficacy of vaccines offered in Hong Kong, but said weeks of tests are still needed to determine how easily it spreads.

The University of Hong Kong’s (HKU) Dr Kelvin To Kai-wang was part of a team which on Tuesday night was revealed to have successfully isolated Omicron a clinical breakthrough in support of global efforts to develop an inactivated vaccine against the new variant.

“This particular strain has all the characteristics of previous mutations and more,” the head of HKU’s department of microbiology told a radio show on Wednesday.

“So I believe [existing vaccines] will not be as effective, but how much it will reduce efficacy is still hard to predict.”

He added: “Whether vaccines could be entirely ineffective, or reduce efficacy by 20 per cent or 40 per cent, is still too hard to say.”

Scientists are broadly in agreement that the heavily mutated variant is likely to reduce the ability of current vaccines to help fight off the coronavirus.

On Tuesday, CEO of United States vaccine manufacturer Moderna, Stephane Bancel, told the Financial Times there would be a “material drop” in the effectiveness of existing jabs against Omicron.

He said researchers were worried by Omicron’s high number of mutations on the spike protein, which current vaccines target to help boost immunity against the coronavirus. Of the variant’s 50 mutations, 32 were spike protein ones.

But rival vaccine maker BioNTech urged people not to worry, saying its vaccines were likely to protect against severe illness requiring hospital treatment.

The German firm, which co-developed its Comirnaty-branded jab with US pharmaceutical giant Pfiser, makes one of the two Covid-19 vaccines used in Hong Kong, the other being developed by Chinese drug maker Sinovac.

BioNTech expects to receive data from laboratory testing on whether adjustments will be needed to its vaccine in about two weeks.

The company said that, if necessary, it could “adapt the mRNA vaccine within six weeks and ship initial batches within 100 days”.

HKU’s To said the team’s success in isolating the variant was of great value to public health policy and to vaccine manufacturers.

He said results from its tests would be published in research papers and made available to all relevant stakeholders.

To added it would take a few weeks before the team’s research could show whether there was any drop in efficacy of existing vaccines against Omicron, or in the immunity levels of recovered Covid-19 patients. A similar period was also required to assess the transmissibility of the variant.

However, William Chui Chun-ming, president of the Society of Hospital Pharmacists of Hong Kong, told the same radio programme that so far there was no evidence to suggest that vaccines were ineffective against Omicron.

“The information available now is quite confusing. In addition to antibodies that help neutralise the virus, vaccines also activate cells in the immune system such as the T-cell to help fight off an infection,” he said.

“There is no evidence yet to show vaccines, particularly the ones by Pfiser, are ineffective.”

Chui also warned unvaccinated people they were at far more risk than those who had been inoculated.

Governments across the world have imposed tough new border controls including outright travel bans since the new variant was first discovered last week in southern Africa.

Hong Kong responded this week by moving a host of countries into its highest-risk Group A category for Covid-19, which requires 21-day quarantine for residents returning to the city and bars non-locals from entering at all.

Meanwhile, HKU microbiologist Dr Ho Pak-leung urged the government to speed up its implementation of a vaccine passport scheme to give inoculated people greater freedom to move about the city.

“The government needs to stop dragging its feet and start by giving residents a clear indication they will definitely do it,” he said.

“They can start by implementing it in high-risk areas where people take off their masks, so residents can better understand the reasoning behind the policy.”


Category: Hong Kong

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