China’s Sinovac offers inadequate protection against Omicron, study shows

Two doses of the Chinese-made Sinovac vaccine, probably the most generally used jabs in China and world wide, present “insufficient” antibodies against the Omicron coronavirus variant, in response to researchers in Hong Kong.

The findings from a study launched by the University of Hong Kong have stoked nervousness as Omicron surges in lots of elements of the globe and the primary two circumstances have been detected in mainland China this week.

China has administered greater than 2.5bn doses of a Covid-19 vaccine — most of them Sinovac or Sinopharm — and adopted a “zero Covid” technique that has subjected huge numbers of individuals to obligatory authorities quarantine. The new coronavirus pressure had already raised questions over the efficacy of Chinese vaccines and Beijing’s capability to maintain the virus beneath management.

“[Omicron] has left the Chinese vaccines even more ineffective against the threat posed by Covid,” mentioned Nicholas Thomas, an affiliate professor on the City University of Hong Kong who specialises in Chinese overseas coverage and well being safety in Asia. “The challenge for the Chinese authorities will be [to] re-engage their population’s commitment to another round of vaccines.”


The Hong Kong study examined the antibody ranges of 25 individuals who obtained each doses of the Sinovac vaccine — an inactivated vaccine in contrast to messenger RNA jabs such because the photographs developed by BioNTech/Pfizer — and located that none had enough antibodies of their blood serum to neutralise the brand new variant.

In distinction, 5 folks out of a gaggle of 25 who got two doses of the BioNTech/Pfizer vaccine have been discovered to have detectable neutralising antibodies against Omicron, which the researchers mentioned had an “efficiency” of between 20 and 24 per cent against the brand new variant.

Last week Pfizer mentioned that three doses of its jab would be capable to neutralise Omicron based mostly on a lab check.

Multiple laboratory research have proven that the antibody protection offered by two doses of any vaccine is dented by Omicron. Separate preliminary research from the University of Oxford and the Medical University of Innsbruck discovered that many double vaccinated Oxford/AstraZeneca recipients didn’t produce any measurable neutralising antibodies against Omicron.


The University of Hong Kong researchers mentioned their study “demonstrated that both Omicron variants have reduced susceptibility to neutralisation by sera collected from Covid-19 vaccine recipients. None of the [Sinovac] recipients had detectable neutralising [antibodies] to the Omicron variants.”

A degree of antibodies enough to neutralise the virus is intently associated to the flexibility to forestall symptomatic an infection, earlier research have proven. However, specialists stress that double vaccinated folks will nonetheless retain some protection against extreme illness as a result of that is mediated by T cells and B cells quite than antibodies.

Kevin To, one of many HKU researchers, advised the Financial Times that information on a 3rd Sinovac dose “would be needed” to find out whether or not those that have had two Sinovac jabs ought to swap to different vaccines for the booster shot.


David Hui, a Hong Kong authorities pandemic adviser from the Chinese University of Hong Kong, mentioned one other study was beneath method on a three-shot course of the Sinovac vaccine to guard against Omicron. The findings are anticipated to be printed subsequent week.

Huge populations in international locations together with Turkey, the Philippines and Indonesia have obtained the Sinovac vaccine. Sinovac, which mentioned on Wednesday its personal lab check outcomes confirmed a 3rd dose may successfully enhance the flexibility in neutralising Omicron, was not instantly out there for feedback on the study.

Nine Omicron circumstances have been recorded in Hong Kong as of Wednesday, simply as remaining preparations for resuming quarantine-free journey to mainland China have been being carried out. A prime adviser to metropolis chief Carrie Lam dismissed issues raised by the study.

“For the time being, Hong Kong is using a zero Covid strategy to prevent infection . . . so no worries yet,” Lam Ching-choi, a medical physician and a member of Lam’s de facto cupboard, advised the FT. “[Omicron] has not [affected border reopening plans] for the time being . . . The Omicron cases were well contained, [with] no [cases] being spread into the community.”

Additional reporting by Oliver Barnes in London

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