Sinopharm booster dose found to be lower against Omicron: study

A Covid booster dose developed by Chinese company Sinopharm has been shown to generate weaker immune responses against the new, highly transmissible variant of Omicron, known to elude the efficacy of the vaccine.

The worrying Omicron hypermuted variant has so far spread to around 90 countries, raising serious concerns about the reduced efficacy of the vaccine and the increased risk of re-infection.

In one study, researchers from Shanghai Jiao Tong University and a Shanghai laboratory specializing in respiratory infectious diseases compared the activity of Sinopharm’s booster vaccine against an older vaccine. coronavirus Wuhan strain.

The study, which has not yet been peer-reviewed, showed that the activity of neutralizing antibodies of a Sinopharm BBIBP-CorV booster against Omicron showed a 20.1-fold reduction, compared to its activity against a Wuhan strain.

The study included 292 healthcare workers who had administered a third homologous booster vaccination eight to nine months after the end of the inactivated two-dose initiation vaccination.

The team investigated whether the newly identified Omicron variant could escape the neutralization of serum antibodies caused by the booster vaccination.

The results showed that a third booster dose with BBIBP-CorV results in a significant rebound in the neutralization of the immune response against SARS-CoV-2. The neutralization titer on day 28 after the third booster dose was 6.1 times higher than on day 28 after the second dose.

However, “the Omicron variant caused a significantly lower neutralization sensitivity than the wild-type strain of the booster serum, with about a 20.1-fold reduction,” Xin-xin Zhang, of Ruijin Hospital , from the university’s medical faculty.

“Our study demonstrated that a third booster dose of BBIBP-CorV resulted in a significant rebound in the neutralizing immune response against SARS-CoV-2. The Omicron variant showed significant but incomplete leakage of the booster caused neutralization . “

A separate study, not yet peer-reviewed, has shown that Sinopharm’s two-dose Covid vaccines also produce little or no antibodies against Omicron.

Led by researchers at the University of Washington and Swiss drug maker Humabs Biomed SA, the study showed that only three in 13 people who took both doses of the Sinopharm injection had neutralizing antibodies against Omicron.

Meanwhile, vaccines developed by US drugmakers Pfizer, Moderna, Johnson and Johnson against Covid-19 have also been shown to be less effective against the new super mutant variant Omicron which harbors up to 36 mutations in the spike protein.

–IANS

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(Only the title and image of this report may have been reworked by Business Standard staff; the rest of the content is automatically generated from a syndicated feed.)

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