The World Health Organization (WHO) issued an emergency use listing for CONVIDECIA, a vaccine produced by Chinese manufacturer CanSino Biologics, making it the third Chinese vaccine validated by the WHO for the prevention of COVID-19.

The vaccine has 64 percent efficacy against symptomatic disease and 92 percent against severe COVID-19, according to the WHO's official statement on Thursday.

CanSinoBIO's shot is based on a modified human adenovirus that expresses the spike S protein of SARS-CoV-2. It is administered as a single dose.

Researchers have found that the Ad5-nCoV booster induced a potent neutralizing activity against the wild-type virus and the Omicron variant, proved to be a better choice for mixed vaccination booster.

The emergency use listing (EUL) for CanSino's shot adds "to a growing portfolio of vaccines validated by the WHO for the prevention of COVID-19 caused by Sars-CoV-2," said the organization.

It is also China's first third-generation COVID-19 vaccine approved by the WHO which uses a relatively harmless, unrelated virus called adenovirus that has been engineered to carry DNA encoding the desired viral protein target such as the SARS-CoV-2 spike protein, according to a statement the producer sent over to the Global Times.

Getting the nod of the WHO means that CanSinoBIO has received a "green pass" in the global market and is expected to be approved for use in more countries that have adopted the WHO validation list for immunization, said experts.

CanSinoBIO's shot was approved to market in China in February last year and has been authorized for emergency use in Mexico, Pakistan, Chile, Argentina, Ecuador, Hungary, Indonesia, and Kyrgyzstan, and obtained GMP certification in the European Union.

Taking CanSino's recombinant adenovirus vector COVID-19 vaccine as a booster shot after two doses of inactivated jabs is proven to be safe and more effective than taking an inactivated vaccine as a booster, research data revealed.

The shot has been adopted or recommended as a booster jab in many countries and regions such as China, the UK, the US, Canada, Chile, Thailand, Brazil, the United Arab Emirates, Peru, and Argentina.

CanSinoBIO's COVID-19 mRNA vaccine and nasal spray vaccines are also under development in clinical stages in China.

In January 2020, at the early stage of the COVID-19 outbreak, CanSinoBIO quickly kicked off its 55-day research and became the first to launch clinical trial in the world. The global multi-center Phase III clinical trial was launched in May 2020, which is also the largest clinical trial of a COVID-19 vaccine in China.

More than 120 COVID-19 vaccine products are currently in clinical trials around the world, of which 27 have been approved for marketing or emergency use domestically while only 11 have emergency authorization from the WHO.