Three doses of Sinovac effective against Omicron


THREE doses of the CoronaVac vaccine are effective against Covid-19 variants including Omicron, according to new data from Sinovac Biotech Ltd.

Based on a study on 120 participants conducted in China, 95% of individuals who received the three doses showed neutralising antibodies against the Omicron variant.

Results from the study supported the use of a three-dose immunisation routine as the seroconversion rates of neutralising antibodies against Omicron jumped to 95% from 3.3% for two and three dose schedules respectively.

Among the participants who received three doses, researchers also isolated 323 human monoclonal antibodies derived from memory B cells, half of which recognise the receptor binding domain and show that a subset of them can neutralise SARS-CoV-2 variants of concerns (VoC).

Moreover, the World Health Organisation (WHO) depicted a variant as a VoC through several reaction: The increase in transmissibility or detrimental change in Covid-19 epidemiology, increase in virulence, change in clinical disease presentation, decrease in effectiveness of public health and social measures or available diagnostics, vaccines and therapeutics.

Sinovac spokesperson Pearson Liu said the study reassures inactivated vaccines to remain effective in fighting Covid-19. This is also aligned with the propositions by WHO and health authorities globally.

“These latest data come in the wake of recent findings that show one month after the second dose, CoronaVac elicits a significantly higher T-cell response, which is important in preventing serious illness, hospitalisation and death, compared to a mRNA vaccine,” he said in a recent statement.

Previously, the WHO approved CoronaVac for the use of emergency or conditional marketing use.

More than 2.6 billion doses of the vaccine had been delivered worldwide with over 250 million administered to children aged three to 17 in China as of January 2022.