Study of Chinese mRNA vaccine candidate shows booster raises effectiveness against Omicron
- The vaccine, ARCoV, jointly developed by three Chinese institutions, is not initially as effective against Omicron variant of Covid-19 as it is against other strains
- No mRNA vaccine developed overseas has yet been approved by regulators, and China has relied on traditional ‘inactivated’ vaccines in fighting coronavirus
A new study has shown that a Chinese mRNA vaccine candidate saw a significant drop in its ability to neutralise the Omicron strand of the coronavirus compared to its effectiveness against a wild-type strain with no major mutations – but that a booster could readily induce the production of the neutralisation antibody.
The vaccine, ARCoV, which is being jointly developed by the Academy of Military Medical Sciences, Suzhou Abogen Biosciences and Walvax Biotechnology, is at the final stage of a multiregional phase 3 clinical trial.
The study analysed serum samples from 11 vaccinated people, eight of whom “retained low but detectable neutralisation activity against Omicron”, researchers said in a letter published in the journal Cell Research on Monday.
A third dose was given to a group of lab mice that had already received two doses of ARCoV, and it readily induced the production of neutralising antibodies against Omicron and a wild-type strain, the letter said – highlighting the benefits of a homologous booster vaccination and supporting further validation of the vaccine in clinical trials.
“Our data presented here clearly demonstrate that a third dose of ARCoV would probably lead to a sharp increase in neutralisation antibodies not only against the WT Sars-CoV-2 but also the new Omicron variant,” the letter said. “Homologous booster vaccination with ARCoV represents a rational strategy in response to the Omicron emergency.”