Larger droplets would train defenses in areas of the mouth and throat, while smaller ones would move further in the body, said Dr. Vineeta Bal, an immunologist in India.
The inhalable vaccine was developed by the Chinese biopharmaceutical company CanSino Biologics Inc. as an aerosol version of the company’s one-time adenovirus vaccine, which uses a relatively harmless cold virus.
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The traditional single-use vaccine has been approved for use in more than 10 markets, including China, Hungary, Pakistan, Malaysia, Argentina and Mexico. The inhaled version has been given the green light for clinical trials in Malaysia, a Malaysian media report said last month.
Regulators in India have approved a nasal vaccine, another needle-free approach, but it has yet to be rolled out. The vaccine, developed in the US and licensed to Indian vaccine maker Bharat Biotech, is injected into the nose.
About a dozen nasal vaccines are being tested worldwide, according to the World Health Organization.
China has relied on domestically developed vaccines, mainly two inactivated vaccines that have proven effective in preventing death and serious illness, but less than the Pfizer and Moderna vaccines in stopping the spread of the disease.
The Chinese authorities have also not mandated vaccination – entering an office building or other public places requires a negative COVID-19 test, not proof of vaccination. And the country’s strict “zero-COVID” approach means that only a small fraction of the population has been infected and built up immunity that way, compared to other places.
As a result, it is unclear how widespread COVID-19 would spread if restrictions were lifted. The ruling Communist Party has so far shown no signs of easing its “zero-COVID” policy, acting quickly to restrict travel and impose lockdowns when even a few cases are discovered.
Authorities on Wednesday ordered 900,000 people in Wuhan, the city where the virus was first discovered at the end of 2019, to be detained for at least five days. In the remote province of Qinghai, the boroughs of the city of Xining have been closed since last Friday.
In Beijing, Universal Studios said it would close its hotels and attractions “to comply with pandemic prevention and control”. The city of more than 21 million people reported 19 new cases in the past 24 hours.
AP
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