More than 2.08 billion doses of COVID-19 vaccines had been administered in China as of Thursday. For months, trials have been underway in China for an inhaled vaccine against COVID-19. CanSinoBIO is also the maker behind China's first single-dose jab. CGTN's Ning Hong pays a visit to its researchers in the port city of Tianjin.

One deep breath can help provide protection against COVID-19. This may well be the reality, as Chinese developers work on an inhaled vaccine. They've said that the first phase of clinical trials has shown promising results.

SI WEIXUE Deputy Director, CanSino Vaccine R&D Department "We are very confident and excited. Whether it's two doses through an inhaled vaccine or an intramuscular injection, the inhaled vaccine can be used as a booster to strengthen antibody immunity, such as Immunoglobulin G. Antibody levels have shown to be better than in the one-shot vaccine we previously approved. The inhaled vaccine can also produce high levels of cellular immunity."

Researchers say, unlike most COVID jabs available, the inhaled vaccine can stimulate a better mucosal immune response in a person's lower respiratory tract, which experts say is the main target of SARS-CoV-2, or the virus that causes COVID-19.

A study published in July in the Lancet Infectious Diseases journal says no serious adverse events were noted within 56 days after the first inhaled vaccine.

For better protection, researchers suggest two doses or a combination of an inhaled vaccine with an intramuscular jab.

SI WEIXUE Deputy Director, CanSino Vaccine R&D Department "Based on the results of our clinical trials, through inhalation only, one dose provides basic immunity while an additional dose heightens protective effect. Using different immunization methods, clinical trials show better protection if the first dose is an intramuscular injection. The inhaled dose boosts the efficacy of the injection."

China approved CanSino's Convidecia in February – a one-shot vaccine against COVID-19.

Researchers say they are now working on the dosing equipment before the inhaled vaccines hit the market.

SI WEIXUE Deputy Director, CanSino Vaccine R&D Department "We have designed a device that can facilitate faster and more convenient drug delivery for doctors and vaccinators. The equipment we developed can accurately administer drugs."

A new production line is now fully operational inside the CanSino plant in Tianjin. This comes as the development of new inhaled vaccine is speeding up.

NING HONG Tianjin "The development of an inhalable vaccine provides an alternative option for the CDC. And it's growing to become a vital factor that will speed up the global efforts to control COVID-19. Ning Hong. CGTN, Tianjin."