Some Omicron sub-variants escaping antibodies from Sinopharm shot - Chinese study
A booth displaying a coronavirus vaccine candidate from China National Biotec Group (CNBG), a unit of state-owned pharmaceutical giant China National Pharmaceutical Group (Sinopharm), is seen at the 2020 China International Fair for Trade in Services (CIFTIS), following the Covid-19 outbreak, in Beijing, China September 4, 2020. PHOTO: REUTERS
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.
The vaccine, BBIBP-CorV, is one of the two Sinopharm COVID shots approved for use in China, and is also the main shot that the state-owned firm has exported.
Among 25 individuals who received two doses of BBIBP-CorV vaccine, the neutralising activity against sub-variants such as BA.2.12.1 and BA.4/BA.5 "was not or only minimally detectable", researchers said in correspondence published on Monday.
Neutralising activity against those sub-variants was observed in just 24-48% of subjects who received a BBIBP-CorV booster shot after the two-dose product, researchers said, citing results from a group of 25 participants.
The rate improved slightly, to 30-53%, for those who received a third shot made by a unit of Chongqing Zhifei Biological Products, another vaccine approved for use in China, according to data from another group of 30 subjects.
The study did not discuss the boosters' efficacy, a rate that reflects how well they could lower the risk of COVID disease or death, which is usually observed in large clinical trials.