Nasal spray effective in preventing COVID and the common cold, study shows

A recent study found that people who took an allergy medicine were much less likely to get sick from COVID-19 and the common cold, the latest research to show promising results for nasal sprays in attacking or blocking respiratory viruses in the nose.

“If we could stop the virus at the front door, that would be great,” said Dr. William Schaffner, a professor of infectious diseases at the Vanderbilt University School of Medicine in Nashville. “The front door for these viruses is our nose and that tissue right in the back of our noses.”

The German study of 450 adults published on Sept. 2 found that those who took azelastine — an antihistamine sold under the brand names Astepro and Astelin — were much less likely to contract viral infections than those who took a placebo. It came after other recent research also suggested that different types of nasal sprays may prevent the transmission of respiratory viruses.

Schaffner, who was not involved in the study, said more testing is needed, because the study involved relatively small numbers of people or were done on animals. Larger studies will determine how effective the sprays are in the real world, and at what dosages and frequencies, he said.

But, he said, viruses must attach to and enter cells to make you sick, and the most common entry point for respiratory viruses is the nose. Scientists believe that medications given through the nose have the potential to be more effective than those injected into the body because they attack or block the virus at the source.

Schaffner said that Trump administration funding cutbacks and shifts in how it approaches COVID-19 vaccines are taking away money from nasal-spray initiatives and could delay the development of nasal vaccines.

Those receiving azelastine in the antihistamine study used it three times a day for an average of 56 days. Researchers found they were about three times less likely to become infected with COVID-19 or with rhinoviruses, which cause the common cold, than people who didn’t. A previous, smaller study on azelastine had roughly similar findings.

Early antihistamine doubts

Antihistamines work by blocking a chemical that causes allergic symptoms. Because of that, during the height of the COVID-19 pandemic, Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Medicine, said she and other physicians wondered whether antihistamines could protect against the coronavirus. But, she said, anecdotally “it did not seem to make a difference.”

What may be different today is that almost everyone has either contracted COVID-19 or received a COVID-19 vaccine, and that could lead to a different type of immune system response, Nachman said.

She cautioned against anyone using azelastine to prevent COVID-19 or colds until after a larger study is conducted and analyzed. 

Scientists have had mixed results in looking at other nasal sprays, such as those made from nitric oxide and a red seaweed.

Research on nasal sprays is not new. There is a federally approved nasal spray — FluMist — used as a flu vaccine. It was first approved for some age groups in 2003 and is about as effective as a traditional shot, Schaffner said.

The increase in research into nasal sprays in recent years is in part because of efforts to find more effective vaccines against COVID-19, said Dr. Paul Spearman, vice chair for clinical and translational research and education at Cincinnati Children’s Hospital Medical Center.

Current COVID-19 vaccines are effective at preventing severe disease, but their ability to prevent transmission wanes within weeks after the shot is given, research shows.

“If you could make a vaccine that prevented the initial infection or prevented the spread, then that would be two steps up above what we’ve got now,” Spearman said.

Promising nose gel

Researchers at Harvard Medical School and Boston’s Brigham and Women’s Hospital last year said they developed a gel-like spray that coats the inner lining of the nose and was almost 100% effective in blocking viruses from infecting the noses of mice, and in a 3D model of the human nose.

There is other research also looking at gels. But the gel must be reapplied to remain effective, Spearman said. In the Harvard research, it remained protective for up to eight hours. It’s unlikely most people would apply a gel every day or multiple times a day for the entire year to prevent getting a cold or COVID-19, Spearman said.

The azelastine findings also indicate that sustained use of the antihistamine is needed to provide protection. The study’s authors said it could be used before going into “high-risk settings, such as large gatherings or travel.” But more research is needed to determine how often and for how many days it should be used.

Spearman led the first U.S. human clinical trial of a nasal COVID-19 vaccine — released in July — that showed that people who received higher doses of the spray were significantly less likely to have COVID-19 symptoms than those getting a low dose. It was of 61 people, and a much larger study is needed, he said.

Spearman said generating an immune response in the nose offers great promise.

“If you do that, then whenever the virus comes around, your immune cells just take care of it, and ideally, you’d prevent the virus from then getting into the lung or getting in anywhere else where it would make you sick,” he said.

David Olson covers health care. He has worked at Newsday since 2015 and previously covered immigration, multicultural issues and religion at The Press-Enterprise in Southern California.