CanSino's one-shot COVID-19 vaccine

The world's first aerosolized inhaled adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV), jointed developed by CanSino Biologics (CanSinoBIO) and researchers from the Institute of Military Medicine under the Academy of Military Sciences led by Chen Wei, was proven safe in Phase-I clinical trials, the Global Times learned from CanSinoBIO on Wednesday.

The trial showed that two doses of aerosol Ad5-nCoV was well tolerated, without causing any vaccine-related serious adverse events, CanSinoBIO said.

The trial found that an aerosolized booster vaccination taken 28 days after the first intramuscular injection "induced strong IgG and neutralizing antibody responses," said the report of the trial, which was published on The Lancet Infectious Diseases on Monday.

The Phase-I trial result was the world's first released clinical data on aerosolized inhaled Ad5-nCoV vaccines. Phase-II clinical studies of the vaccine are ongoing, CanSinoBIO told the Global Times on Wednesday.

The Phase-I trial, conducted in Zhongnan Hospital in Wuhan, Central China's Hubei Province, randomly assigned participants into five groups to be vaccinated via intramuscular injection, aerosol inhalation, or both, the report said. 

More adverse events were reported in participants who received intramuscular vaccination, including participants in the mix group (49 of 78 participants; 63%), than those who received aerosol vaccine (13 of 52 participants; 25%) after their first vaccination. The findings showed the aerosolized inhaled vaccine is relatively tolerable and safe.

Also, one-dose of aerosolized Ad5-nCoV, equal to one fifth of an intramuscular dose, could induce a strong cellular response, and two doses of aerosolized Ad5-nCoV could produce similar SARS-CoV-2 neutralizing antibody titers as one dose of intramuscular vaccination, the trial found.

CanSinoBIO obtained the national drug regulator's approval on March 23 to start clinical trials of its recombinant COVID-19 vaccine (adenovirus type-5 vector) in inhaled form.

The Global Times learned that the vaccine 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 makes it less painful and more accessible, especially for children and vulnerable people, experts said, as it avoids regional pain and swelling.

What's more, the inhaled form requires only one fifth of the dosage of an injected one, which preserves more doses and relieves production pressure. 

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 preferred to not be identified, told the Global Times in a previous interview.