May 9, 2022 -- Scientists are working on COVID vaccines delivered through nasal sprays that could stop the coronavirus from invading the body at its most common entry point, the mucous membrane of the nose and throat.
More than a dozen clinical trials with nasal sprays are under way, The Guardian reported.
USA Today said Vietnam, Thailand, Brazil, and Mexico have already started manufacturing the nasal vaccine in anticipation of success in the clinical trials.
A nasal vaccine would probably be employed as a booster in the United States but might be widely used in less-developed parts of the world where injectable vaccines are not common, USA Today reported.
While injectable vaccines help the body ward off severe illness, nasal vaccines could stop the virus from entering the body in the first place. The effectiveness of injectable vaccines wanes over time, and COVID variants can evade the vaccines, as evidenced by the high number of Omicron cases.
“If you think of your body as a castle, an intramuscular vaccination is really protecting the inner areas of your castle so once invaders come in, that immunity protects against them taking the throne,” Sean Liu, MD, medical director of the Covid clinical trials unit at the Icahn School of Medicine at Mount Sinai in New York City, told The Guardian.
“But if you train your immune system to work at the gates of the castle, then the invaders not only have trouble getting in, but they may have trouble spreading inside.”
A nasal vaccine could be more easily manufactured and distributed because it’s stored in a regular refrigerator rather than ultra-cold temperatures like the Moderna and Pfizer mRNA vaccines. People who don’t like needles might accept a nasal vaccine.
And it would be much cheaper to produce, USA Today said. Peter Palese, who is also working on nasal vaccines at the Icahn School of Medicine, said a nasal dose could be produced for about 30 cents compared to $30 for a Moderna or Pfizer dose.
Scientists face many challenges in their research, especially measuring the strength of the immune response to the nasal vaccine.
Different techniques are being used to develop the nasal spray. At the Icahn School of Medicine, they’re making the vaccine in eggs, like flu vaccines. The Cincinnati Children's Hospital in Ohio is trying a canine flu, USA Today said. A nasal version of the Oxford/AstraZeneca vaccine is based on a weakened adenovirus, The Guardian reported.
In January 2021, researchers from Lancaster University in England and Texas Biomedical Research Institute in San Antonio reported that rodents given two doses of a nasal vaccine had antibody and T-cell responses that were strong enough to suppress SARS-CoV-2.