SHANGHAI, Oct. 28 (Xinhua) -- People in Shanghai now have the choice to get vaccinated against COVID-19 in a new way: through the mouth.
Since this week, the Chinese city has started administering a needle-free COVID-19 vaccine, which can instead be aerosolized and inhaled by vaccine takers.
"It takes just a few seconds to breathe in," a resident said after the oral administration at a local vaccination site on Wednesday. "It's much easier than getting a shot," said the vaccinee, who had received two intramuscular jabs before.
The inhalable booster is an adenovirus type 5 vector-based vaccine, jointly developed by a research team led by Chen Wei, an academician at the Chinese Academy of Engineering, and the Chinese biotech company CanSino Biologics Inc. It is being offered only as a booster dose for previous COVID-19 vaccine recipients.
"The inhaled dose is 0.1 milliliter. Vaccinees need to put the nozzle of a white bottle into their mouths, inhale the gas inside deeply, and hold a breath for at least five seconds to finish the procedure," said He Jinhui, a local hospital nurse, who explained the basic vaccination instructions.
Although the inhaled dose is only about a fifth of a traditional intramuscular vaccine dose, it can elicit a stronger immune response.
Zhu Tao, a chief scientist at CanSino, said that compared with injection, inhalation can stimulate one more type of immune response -- mucosal immunity.
"The inhalable vaccine can effectively increase the level of neutralizing antibodies in body fluids, and also produce IgA antibody in the respiratory mucosa, which can strengthen the current vaccines' ability to prevent Omicron from infecting the upper respiratory tract," Zhu professed.
The needle-free vaccine is not only less painful but also tastes a little sweet, some vaccinees found.
Zhu said the sweet flavor was due to the very low concentrations of sucrose that were added to the vaccine, which can help improve the stability of the viral vector.
Researchers conducted a randomized clinical trial last year to evaluate the booster vaccine's safety and immunogenicity as a booster jab in 420 Chinese participants. The results were published in the journal Lancet Respiratory Medicine, showing that it is well tolerated and can induce high neutralizing antibody levels against COVID-19 in adults.
China has approved the inhalable vaccine for emergency use among populations aged 18 and above who had received two doses of traditional vaccines, but not within the previous six months. The vaccine developer said it was planning to apply for expanding the oral vaccination reach.
"I am afraid of needles and injection pain. I think the inhaled vaccine must be easier to administer," said a Shanghai resident surnamed Ding, who made a vaccination appointment on Wednesday. ■
