Nasal COVID-19 vaccine heads for human testing

April 3 (UPI) -- Researchers in Germany said a trial of COVID-19 vaccination administered through the nose has shown great promise in animal testing, and they are preparing for first-stage clinical trials in humans.

The results of the nasal vaccine research were published Monday in the scientific journal Nature Microbiology.

Authors from the Freie Universität Berlin, Max Delbrück Center and Charité - Universitätsmedizin Berlin said they developed a nasal vaccine that attacks COVID-19 where it often enters the body.

The body often expels droplets of saliva containing the virus while breathing and talking, coughing, sneezing or laughing. Other people then breathe in the airborne pathogens and become infected.

Researchers said India and China had already approved nasal vaccination formulations last fall. They took modified adenoviruses, which typically cause respiratory or gastrointestinal illnesses, that either replicate poorly or stop replicating altogether, therefore never triggering the disease.

In nasal vaccination tests on hamsters, scientists found after two doses of the vaccine that COVID-19 could no longer replicate itself. They said hamsters are a key model in research because they are infected similarly to humans and develop the same symptoms.

"It is here, therefore, that we need local immunity if we want to intercept a respiratory virus early on," said a study co-author, Dr. Jakob Trimpert, a veterinarian and research group leader at the Institute of Virology at Freie Universität Berlin.

The scientists said they believe a nasal treatment helps fight COVID-19 where it first takes on in the human body -- in the mucous membranes of the nose, mouth, throat, and lungs.

"Nasal vaccines are far more effective in this regard than injected vaccines, which fail or struggle to reach the mucous membranes," said Dr. Emanuel Wyler, a study co-author.

Researchers said that their vaccine stimulates the formation of the antibody immunoglobulin A or, IgA, which prevents infection from occurring in the first place. The antibody is the most common immunoglobin in the mucous membranes of the airways.

"Memory T cells that reside in lung tissue play a similarly useful role to antibodies in the mucosa," Geraldine Nouailles, an immunologist and research group leader at the Department of Pneumology, Respiratory Medicine and Intensive Care Medicine at Charité.

"These white blood cells remain in affected tissue long after an infection has passed and remember pathogens they have encountered before," said said. "Thanks to their location in the lungs, they can respond quickly to viruses that enter through the airways."

Researchers said the nasal vaccine used in India and China has not been approved in Europe. They said, though, that future study is needed because the vaccines would be inexpensive to produce with a much longer shelf life than current options.

The study comes as cases in the United States continue to drop. According to the Centers for Disease Control and Prevention, 139,991 cases were diagnosed for the week ending March 29, down from 154,244 the previous week.

That represents some of the smallest weekly infection numbers since summer 2021, when cases were below 100,000.