How China approves inhaled Covid vaccine

China has become the first country to approve an inhaled Covid vaccine.

Made by CanSino, it has similar ingredients to its injected vaccine, using a harmless adenovirus as a carrier for the genetic code that teaches the body how to fight Covid.

Inhaled as a fine mist, Convidecia Air can provide good protection after just one breath, the company says.

Other researchers, including teams in the UK and the US, have been investigating nasal spray vaccines.

Scientists say these may give added immunity in the lining of the nose and upper airways, where Covid typically enters the body.

The National Medical Products Administration of China granted CanSino approval for its inhaled vaccine to be used as a booster dose.

It can top up protection in those who have previously had a jab, trials suggest.

Meanwhile, the latest Covid vaccine booster programme has begun in England, Wales and Scotland.

Infections are falling around the UK - but health bosses predict a resurgence of Covid and flu this autumn and winter.

They are urging those eligible to protect themselves from serious illness by being vaccinated against both.

University of Hong Kong virologist Jin Dong-Yan, who was not involved in the development of the vaccine, said that it was difficult to say what impact the product would have if used in China, as more data was needed to understand the protection it offers, including against infection.

However, shots that could offer so-called mucosal immunity by being delivered in the nose or mouth could be a good option for use as additional boosters in China, Jin said, given the low levels of natural immunity in its population, where only a small fraction of people has had Covid.

Studies have indicated that people who have been infected with Covid gain this kind of immunity, which is not the focus of protection for injected vaccines.

"These (kinds of vaccines) might be particularly important for China, because all over the world in the general population, we have a mixed type of immunity (from both vaccination and natural infection) ... and (these vaccines) might be similar to natural infection in terms of inducing mucosal immunity," he said, adding real world data was needed to confirm this.

"Different types of (second-generation) vaccines should be studied and developed to help boost the herd immunity in the general population, which is a big issue (for) China," he said.

In a news release, CanSino said Convidecia Air "can induce strong humoral, cellular and mucosal immunity."

The manufacturer didn't provide data to support those claims, but referred to studies in The Lancet medical journal.

In a small study published in August, CanSino researchers reported that in people who'd had two injected doses of the CoronaVac vaccine, a booster of the inhaled vaccine increased antibody levels compared with a third injected dose of CoronaVac.

CoronaVac, a shot developed by Beijing-based Sinovac used widely in China and globally, uses a different kind of technology from Convidecia, so the inhaled dose provided a heterologous, or mix-and-match, boost.

The study didn't test whether the inhaled dose kept people from getting infected or preventing them from passing Covid on to others.

Globally, drug manufacturers are racing to make next-generation vaccines that can improve protection against Covid, including those that use innovative methods of delivering doses.

Clinical trials are underway to test more than a dozen spray vaccines to see if they can create mucosal immunity. This boosts certain antibodies in the nose and mouth, specifically, with the goal of preventing an infection from taking hold in the first place.

There's hope that these non-shot vaccines, which are given as drops, sprays or tablets to the mouth and nose, may also prevent the infection from spreading from person to person -- something injected vaccines don't do very well following the emergence of new variants of the virus.

CanSino's Convidecia vaccine is similar to the Johnson & Johnson and Oxford AstraZeneca vaccines. It uses a harmless virus called an adenovirus to ferry instructions for making Covid's spike proteins into cells so the body can create antibodies against them.

None of CanSino's products have been authorized for use in the United States, but the World Health Organization earlier this year listed the injected version of Convidecia for emergency use.