Beijing: China’s Shanghai on Wednesday started administering the world’s first inhalable COVID-19 vaccine. The vaccine, a mist that is sucked in through the mouth, is being offered for free as a booster dose for previously vaccinated individuals, media reports said.

A video posted by an online Chinese state media outlet showed people at a community health center sticking the short nozzle of a translucent white cup into their mouths, reports news agency AP.

Accompanying text said that after slowly inhaling, one individual held his breath for five seconds, with the entire procedure completed in 20 seconds.

“It was like drinking a cup of milk tea,” one Shanghai resident said in the video. “When I breathed it in, it tasted a bit sweet.”

A vaccine taken in the mouth could also fend off the virus before it reaches the rest of the respiratory system, though that would depend in part on the size of the droplets, one expert said.

Larger droplets would train defenses in parts of the mouth and throat, while smaller ones would travel further into the body, the report quoted Dr. Vineeta Bal, an immunologist in India as saying.

Chinese regulators approved the vaccine for use as a booster in September. It was developed by Chinese biopharmaceutical company Cansino Biologics Inc. as an aerosol version of the same company’s one-shot adenovirus vaccine, which uses a relatively harmless cold virus.

The report said that Cansino has said the inhaled vaccine has completed clinical trials in China, Hungary, Pakistan, Malaysia, Argentina and Mexico.