On Sunday, China’s government approved CanSino Biologics’ inhaled COVID-19 vaccine for use as a booster dose. CanSino is a private, Tianjin-based vaccine maker that has partnered with the Chinese military-run Academy of Military Medical Sciences to produce COVID-19 vaccines. The inhaled vaccine uses the same technology as the firm’s World Health Organization–approved viral vector COVID-19 vaccine. The new version is breathed in through the mouth, and clinical trial data showed that it was more effective as a booster at preventing infections from Omicron and other variants than the injectable, inactivated vaccine from Chinese firm Sinovac. CanSino’s new vaccine is not just the first inhaled vaccine for COVID, it is the first inhaled vaccine for any disease.

The vaccine is “a game changer,” Pierre Morgon, an executive vice president at CanSino Biologics, told Fortune. “This is the first-ever inhaled vaccine to be commercialized. I’m so proud to be part of it.”

For now, the vaccine will only be available in China. But Morgon said he hopes that CanSino’s inhaled vaccine will be approved in more countries by the end of the year.

Some scientists in the U.S., meanwhile, have been calling on the Biden administration and vaccine manufacturers to step up efforts to produce an inhaled or nasal spray vaccine because of the technology’s potential to reduce transmission more effectively than injectable immunizations.

Eric Topol, professor of molecular medicine at Scripps Research in San Diego, and Akiko Iwasaki, immunobiology professor at Yale University, urged the U.S. government to create an “Operation Nasal Vaccine” similar to Operation Warp Speed, which funded initial COVID-19 vaccine development, in a July piece for Science Immunology.

“With [Omicron] there has been a marked falloff in the capacity for vaccinations and booster shots to block infections and transmission,” Topol and Iwasaki wrote. They explained that blocking transmission and preventing breakthrough infections have become a “major unmet clinical need” that nasal vaccines may be able to fix.

“Intramuscular shots alone…do not provide tissue-level mucosal immunity,” they wrote. “The only path to achieve this will be via nasal or orally administered vaccines.”

Topol and Iwasaki said there were 12 nasal spray vaccines in clinical development globally, but it appeared unlikely that one would hit the U.S. market soon. The U.S. Food and Drug Administration has approved only one nasal spray vaccine—for the flu—and has never approved an inhaled vaccine.

U.S. President Joe Biden’s administration has signaled that it’s open to new vaccine delivery methods.

“[We are supporting] innovations like nasal sprays and skin patches, instead of needles, to administer vaccines in a more comfortable and accessible way so that everyone in America and around the world can readily benefit from them,” Alondra Nelson, the White House’s deputy director for science and society, said in July at a summit on the future of COVID-19 vaccines.

But even at the summit, it was unclear how the U.S. government would fund the development of new COVID-19 vaccine technology. Last spring, Biden failed to strike a deal with Congress for more funding for the government’s pandemic response, and the two sides have been in a stalemate over the matter ever since.

Morgon said a relatively simple process turned CanSino’s injectable vaccine into a huffable one.

CanSino’s inhaled vaccine uses the same technology as its successful viral vector COVID-19 vaccine. Essentially, CanSino takes the liquid used in its injectable vaccines and turns the solution into a mist with a device called a nebulizer. Patients inhale the mist and hold it in their lungs for 15 seconds or so before breathing out.

“It’s the exact same thing: same composition, same ingredients,” Morgon said of the two vaccines. “The only difference is the dose.”

There is nothing stopping other vaccine makers from developing their own inhaled vaccines, CanSino said.