China has become the first country to approve an inhaled Covid vaccine.
The inhaled Convidecia Air vaccine contains ingredients similar to the injected version of the vaccine, with a harmless adenovirus as a carrier.
Convidecia Air reportedly provides protection after just one breath, CanSino said - the company that produced the vaccine.
Researchers, including teams in the UK and the US, have been investigating nasal spray vaccines.
Scientists said these may even give added immunity in the lining of the nose and upper airways, where Covid typically enters the body, reports the BBC.
The National Medical Products Administration of China granted CanSino approval for its inhaled vaccine to be used as a booster dose.
It comes as the Covid-19 booster vaccine programme has got underway in England and Scotland today with millions of people in line for another jab.
More than 700 care homes in England will be visited by vaccination teams from Monday, with thousands more jabs scheduled before the end of the month.
From Wednesday, around seven million people in England, including those aged 75 and over, and the immunosuppressed, will be able to book a jab online or by calling 119.
Adults aged 50 and over, those aged five to 49 with health conditions that put them at greater risk, pregnant women, care home workers and the household contacts of people with weakened immune systems, will all be eligible for a booster during the rollout.
The NHS will contact people when it is their turn to book their vaccine.
Although infections are falling, health experts are predicting a resurgence of coronavirus this winter amid a possible worse flu season.
Two vaccines have been approved that can be used as boosters this autumn and winter - one from Moderna and the second from Pfizer.
Both have been approved by the Medicines and Healthcare products Regulatory Agency (MHRA) to target both the original and Omicron strains of the virus.
