Three Sinovac Doses Failed to Protect Against Omicron in Study

According to a study by the University of Hong Kong and the Chinese University of Hong Kong, people who are fully immunized with a vaccine called CoronaVac, taking a booster shot from Germany’s BioNTech SE significantly improved the protective levels of antibodies against Omicron.

Two doses of the BioNTech shot, known as a comirneti, were also insufficient, although adding a booster with a more potent mRNA vaccine increased protection to a sufficient level, the researchers said in a statement. The findings are in line with the results reported by the vaccine manufacturers.

Last week, Sinovac released a laboratory study saying that 94% of people who received three doses had neutralizing antibodies, although it did not specify at what level. Researchers in Hong Kong set a threshold for antibody levels sufficient 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 as to how Sinovac’s shot lasts until Omicron – including how T cells, the immune system’s weapon against virus-infected cells, will respond – the preliminary results are a blow to people who have received CoronaVac. . There have been more than 2.3 billion doses of the shot produced and shipped mostly in China and developing countries.

With Omicron known to be about 70 times more permeable than the Delta version, the prospect of rolling out a different booster shot or re-vaccination with an even more Omicron-specific vaccine is likely to get the world out of the pandemic. efforts will be set back.

The research, led by Malik Peiris and David Hui, examined the production of virus neutralizing antibodies in the blood of people vaccinated with two shots currently in use in Hong Kong. They confirm that two doses of either vaccine were not enough to stop Omicron.

The news comes as Hong Kong’s medical advisors cleared the way for adults in the city to receive booster shots, regardless of the vaccine they initially received. The new study shows that there are significant differences between them.