A study in Hong Kong has revealed that the vaccine made by China’s Sinovac Biotech failed to provide adequate protection against the Omicron variant COVID-19, even after a booster injection was given.
On Thursday 23rd December, researchers from the University of Hong Kong and the Chinese University of Hong Kong asked people to get a booster shot made by Pfizer to protect themselves against the Omicron strain of COVID-19.
The study published on Thursday revealed that the CoronaVac injection failed to protect people from the Omicron variant, even after three doses.
“The CoronaVac third dose given to those who received two doses of the previous CoronaVac does not provide adequate protective antibody levels,” the researchers said.
“Those who have received two doses of Comirnaty or CoronaVac should receive a third dose of Comirnaty (Pfizer) vaccine approximately six months after their second vaccine dose to achieve optimal protection against the Omicron variant,” said Professor Malik Peiris, co-author of the study, said in a statement.
The laboratory-based study investigated the neutralizing activity in the blood of people inoculated with the Pfizer or Sinovac vaccine, both of which are currently being used in Hong Kong.
The investigators also noted that two doses of Pfizer’s injection did not provide an adequate level of protection, although the booster dose provided sufficient neutralizing capacity.
Last week, Sinovac cited laboratory studies that said 94 percent of people who took three doses of CoronaVac produced neutralizing antibodies. The level of these antibodies was not stated.
Despite concerns about the efficacy of the Sinovac vaccine, approximately 2.3 billion doses have been manufactured and shipped globally, most of which have been injected in China and developing countries.
Many Western countries have embarked on ambitious campaigns in light of research showing Omicron variants can evade vaccine-induced immunity after two doses of Pfizer, Moderna, or AstraZeneca vaccines.
While the researchers suggest the Omicron variant is less virulent, it is understood to be about 70 times more infectious than the Delta strain.