The World Health Organization on Thursday authorised the use of Chinese manufacturer CanSinoBIO's single-shot Covid-19 vaccine -- the ninth jab to get the WHO green light.

The WHO granted emergency use listing (EUL) to the Tianjin-based firm's Convidecia vaccine as China battles a resurgence of the virus triggered by the Omicron variant.

It is the third Chinese-made vaccine to be approved by the WHO, after Sinovac and Sinopharm.

Convidecia was found to have 64 percent efficacy against symptomatic disease and 92 percent efficacy against severe Covid-19, the WHO said.

"The vaccine meets WHO standards for protection against Covid-19 and ... the benefits of the vaccine far outweigh risks," the UN health agency said in a statement.

The WHO's vaccine experts recommended it for people aged 18 and above.

The jab has already been rolled out in China, Argentina, Chile, Malaysia, Mexico and Pakistan.

The WHO has now given EUL status to nine Covid-19 vaccines and variations thereof -- Pfizer/BioNTech, AstraZeneca, Janssen, Moderna, Sinovac, Sinopharm, Bharat Biotech, Novavax and now CanSinoBIO.

The UN health agency began reviewing rolling data on the CanSinoBIO vaccine in August.

The WHO says EUL approval gives countries, funders, procuring agencies and communities assurance that the vaccine has met international standards.

WHO's listing paves the way for countries to approve and import a vaccine for distribution quickly, especially those without an international-standard regulator of their own.

It also opens the door for the jabs to enter the Covax global vaccine-sharing facility, which aims to provide equitable access to doses around the world, particularly in poorer countries.

China -- the last major global economy sticking to a rigid zero-Covid policy -- is battling an economic slump due to prolonged virus lockdowns that have constricted supply chains, quelled demand and stalled manufacturing.