A small Chinese study detailed in The Lancet Infectious Diseases journal showed neutralising antibodies against some Omicron sub-variants were largely undetectable after two doses of a Sinopharm COVID-19 vaccine, with a booster shot only partly restoring them.
The study comes as China, which has approved only locally developed COVID shots including the Sinopharm vaccine, strives to improve vaccination rates, maintaining a "dynamic zero COVID" policy aimed at eradicate all outbreaks while many countries have adopted an approach of learning to live with the virus.
