In what is believed to be a world first, Shanghai this week introduced a new type of Covid-19 vaccine that is inhaled rather than administered via injection.

Mainland regulators approved the vaccine, produced by Chinese pharmaceutical firm CanSino Biologics, for use as a booster in September.

And now the first people are starting to receive the vaccine, which is inhaled via the mouth from a vessel that looks like a take-out coffee cup with a short mouthpiece.

"Our body’s first line of defence is the mucus membrane of our respiratory system, we want that to be directly stimulated to improve immunity and using the inhaled vaccine does that," Dr Zhao Hui, chief medical officer at Shanghai United Family Hospital Pudong, said.

His hospital is among those administering the new vaccine, which will be used as well as regular injected shots.

Commenting on what he said was a first use of the technology, Erwin Loh, chief medical officer at St Vincents Health Australia, said the advent of inhaled vaccines was important not only because of their potential to guard against infection, but also because they could lessen vaccine hesitancy.

"There is a large proportion of people who are resistant to take the vaccine because they have a needle phobia. They may not articulate it, but that's what in their mind," he said.

A person surnamed Yuan, who received the inhalable booster told the Global Times newspaper he felt that it was "very convenient", adding it is good for people who are afraid of needles.

A 36-year-old Shanghai resident, surnamed Shen, told the paper: "The whole process is very convenient. It also tastes a little bit sweet.” (Additional reporting by Reuters)