A needle-free COVID-19 vaccination with a sweet twist became available in Shanghai starting on Wednesday, and those who fear needles or appreciate the convenience rushed to get the vaccine dose.

"It is quite a pain-free and easy process," said Ma Haitao, who made an online appointment and came to Tianshan Traditional Chinese Medicine Hospital in Shanghai's Changning district for the vaccine dose on Wednesday.

The dose is administered via a cup containing the aerosol of the vaccine. The recipient takes a deep breath from the cup, holds the breath for around five seconds and then slowly exhales.

"It tasted a little bit sweet," said Ma.

Shanghai announced on Tuesday that it would provide an inhaled version of CanSino Biologics' injected COVID-19 vaccine as a booster dose for people age 18 and above, making it the first in the country to offer the inhalable vaccine, which was approved by China's top drug regulator in early September.

Tianshan Traditional Chinese Medicine Hospital opened its vaccination service at 8:30 am on Wednesday, and in the morning alone, more than 30 people had received the vaccine, according to hospital workers.

The municipal government said in a notice released on Tuesday that only people who have finished the primary inoculation and have not received their first booster shot will be eligible for the inhaled vaccine.

The inhaled dose — like widely used vaccines delivered via injection — is not recommended for those experiencing acute symptoms of chronic illnesses or people who are allergic to components of the vaccine.

In Shanghai, which has a population of about 25 million, 23 million people have been fully vaccinated and 12 million have received a booster dose. "The new arrangement is made under the guidance of the State Council's Joint Prevention and Control Mechanism," the government said.

So far, the inhaled vaccine is available at 25 vaccination sites in Shanghai.

Experts and authorities are pinning their hopes on aerosolized COVID-19 vaccines to turbocharge the global fight against the pandemic, because such vaccines can reportedly stimulate immune responses on the mucosal surfaces — the thin skin covering the inside surface of parts of the body such as the nose and mouth — where viruses enter the human body.

CanSino Biologics, the vaccine's developer, said in a preprint study released in late July that when delivered as a booster dose, the inhaled vaccine is capable of stimulating a stronger antibody response in fully vaccinated adults than the injected, inactivated vaccine. No severe adverse reaction has been observed.

The vaccine was granted emergency use authorization from the National Medical Products Administration on Sept 4.

Li Hongzhe, who received the vaccine on Wednesday, said he had been closely watching the development of the vaccine and was drawn to its unique way of triggering protection in the mucous membranes that line the mouth.

"It might offer better protection, in my view, and that's why I wanted to give it a try," he said.

Contact the writers at wangxiaoyu@chinadaily.com.cn