Sinovac and Pfizer vaccines would not be effective against omicron, according to Chinese study

An investigation by the University of Hong Kong determined that neither the CoronaVac vaccine against COVID-19 developed by the Chinese Sinovac nor the American-German Pfizer-BioNTech would be effective against the new omicron variant, local media reported today.

According to the results of the study, collected by the South China Morning Post, neither of these two vaccines induced the antibody response necessary to neutralize the variant first detected in South Africa less than a month ago.

The research – still pending peer review before publication and led by the prestigious infectious disease expert Yuen Kwok-yung – was based on the analysis of blood samples from fifty people, 25 of them immunized with the complete scheme of CoronaVac and the other 25, with Pfizer.

In those who had received the vaccine Sinovac no levels of antibodies were found capable of neutralizing the omicron variant, while those immunized with that of Pfizer-BioNTech, only five showed “detectable” levels, which were still 35 to 40 times less effective than the original variant of the virus and “significantly” less than the Beta and Delta variants.

The Chinese pharmaceutical vaccine is based on the use of the inactivated virus while that of Pfizer-BioNtech employs the innovative biotechnology of messenger RNA.

“The recipients of these vaccines and even patients who have overcome the disease have a greater risk of contagion or reinfection”the study authors cautioned, which focused exclusively on the immune response.

They also indicated, based on the preliminary results of the investigation, that booster doses of both vaccines might be necessary to improve protection levels, without ruling out the need to create next-generation vaccines.

Sinovac It has already announced in recent days that it is working on the development of a version of its immunogen specifically directed at the omicron variant.

Its current formula (CoronaVac) received emergency use approval from the World Health Organization (WHO) on June 1, becoming, after the one developed by Sinopharm, the second Chinese formula to obtain this permission.

Studies – prior to the appearance of the delta and omicron variants – indicate that the Sinovac vaccine is only 51% effective in reducing symptomatic cases of covid-19, although the percentage rises to 100% for severe cases and those that require hospitalization.