Beijing residents can start making appointments for an inhalable Covid booster made by CanSino Biologics, media reported on Thursday, while those in Tianjin city can now get it as the Chinese pharmaceutical firm distributes more supplies.

CanSino's vaccine, called Convidecia Air, is an aerosol version of an inactive shot and was approved as an emergency-use booster by Chinese health authorities in September.

The financial hub of Shanghai and 13 cities in the eastern province of Jiangsu have already introduced the CanSino vaccine as a booster, the company said.

Appointments for the vaccine in the capital can be booked on a mobile phone app for residents of one district, the official Beijing Business Daily reported on Thursday.

Increasing the uptake of vaccinations is vital for China, which is sticking resolutely to its strict zero-Covid policy that aims to prevent large-scale outbreaks and fatalities, especially among the elderly.

China has relied on domestically produced, inactivated shots and has yet to import, or introduce its own version of an mRNA vaccine. According to official data, more than 90 percent of China's population has been vaccinated.

Regarding the efficacy of its vaccine, Hong Kong-listed CanSino said in a statement on Wednesday studies showed "using Convidecia Air as a heterologous booster generated much stronger immune responses than those induced by a homologous inactivated vaccine booster".

The vaccine will be available in Tianjin from Thursday, it said.

The Hong Kong shares of CanSino rose as much as 11.8 percent to HK$119.80 on Thursday, their biggest gain since Nov 4.

- Reuters