CanSino Bio Photo:VCG

China's leading vaccine producer CanSino Biologics obtained the national drug regulator's approval on Monday to start clinical trials of its latest recombinant COVID-19 vaccine (Adenovirus Type 5 Vector) in inhalation form.

The Global Times learned that the vaccine, which was developed in cooperation with the Institute of Military Medicine under the Academy of Military Sciences, is no different in terms of virus species, cell banks, production technology or preparation formula from the company's single-dose Ad5-nCoV COVID-19 vaccine, which is already in use - it just has an additional atomization inhalation device.

The inhaled vaccine can stimulate an immune response in the mucous membranes of a person's respiratory tract. This version is less painful and more accessible, especially for children andvulnerable people, experts said.

The vaccine can be atomized into tiny particles in a device and then inhaled into the respiratory tract and lungs to stimulate mucosal immunity, a Beijing-based immunological expert who prefers to be not identified told the Global Times.

Research has confirmed that respiratory droplets and close contact are still the main transmission routes of the novel coronavirus. 

Mucosal immunity acts as the first barrier against the virus and is essential for the prevention of both mild and severe cases, Jiang Chunlai, a professor at Jilin University's School of Life Sciences, told the Global Times.

"We have seen intranasal vaccines against influenza in China. But there have been limited clinical studies on inhaled vaccines. Not all viruses are suitable for inhalation, so further clinical trials are needed," Jiang said.

Clinical trials also need to be conducted to determine the dosage of the nasal spray vaccine, which may be less than the traditional injection, Jiang noted.

CanSinoBIO has tried to improve and accelerate the induced immune level of its COVID-19 vaccine by multiple delivery methods, including intramuscular injection or inhalation.

Researchers from the University of Hong Kong, Xiamen University and Beijing Wantai Biological Pharmacy used a similar mechanism to develop China's first nasal spray vaccine against the novel coronavirus in November 2020.