In-Depth: Nasal vaccines could provide better protection against COVID infection

Studies show promising results
Posted at 8:51 AM, Jun 07, 2022
and last updated 2022-06-07 12:06:04-04

SAN DIEGO (KGTV) - The best protection against COVID-19 could come through the nose.

Researchers around the world are studying the effects of nasal vaccines. They believe it will offer a better way to prevent infection, since the SARS-CoV-2 virus typically enters the body through people's noses and upper respiratory systems.

"The whole idea is to get a vaccine to train the immune cells in our nose and throat, which are the first immune cells to see the virus when it comes in, in how to fight it," explains Dr. Davey Smith, an infectious disease specialist at UC San Diego.

He says there's something "special" about mucosal immunology, or immunity that begins in the mucus lining of the upper respiratory tract. Dr. Smith adds that mucosal immunity spreads to the blood, the lymph nodes, and the spleen - all places where immune cells live. It would then give system-wide immunity.

"Maybe we can stop Omicron from getting a hold so people can not get sick if they were exposed," he says.

That's the theory behind a handful of studies around the world, all of them looking at nasal vaccines as a solution to the pandemic.

One study from India is the furthest along. It tested a nasal spray on hamsters, with a type of vaccine that uses a weakened form of the coronavirus. The researchers used that as a booster vaccine in animals that were already inoculated with an mRNA shot. They called it the "prime and spike" method.

Compared to the traditional two-shot method, the study found the nasal vaccine boost "reduced replicating virus levels below the detection." It also "prevented inflammation and pneumonia more efficiently than other vaccines." And the nasal vaccine created "markedly higher neutralization capacities." They believe this shows it works better than two mRNA shots.

Another study from Hong Kongfound that a single dose of the nasal vaccine "resulted in sterilizing immunity in both the upper and lower respiratory tracts of hamsters, thus preventing viral spread". They say it shows a nasal vaccine can prevent infection.

And a third study at Yale University found a nasal booster "enhances systemic immunity" better than a shot in the arm.

Dr. Benjamin Israelow, one of the lead researchers on the Yale study, says their findings show mice and hamsters who got a nasal vaccine had decreased viral shedding and decreased transmission of the virus compared with animals that got a shot.

"We're able to inhibit virus replication, in our case, in mice models of SARS-CoV-2. Not only in the lower respiratory tract, but also in the upper respiratory tract," he says.

"Developing immunity within the respiratory tract is key to stopping not just progression of disease, but also transmission."

Dr. Israelow says there are benefits beyond increased protection. Having a nasal vaccine means people who are afraid of needles can get immunized. It's also easier to administer, so people won't need a doctor or nurse to give them the vaccine. That makes it easier to get vaccines into underdeveloped countries and build immunity around the world.

The idea of fighting COVID through the nose is not new. Back in 2020, ABC 10News profiled Diomics, a company working on a spray to give temporary protection against infection. It would cover the nasal cavity with nanobeads that block COVID-19 spike proteins from attaching to cells. Diomics said protection would last about two days.

And San Diego-based Sorrento Theraputics is already testing a nasal drop called "COVI-Drops" as a way to treat people who are already infected. They say this treatment is 10 times more effective than Monoclonal Antibodies, while also being easier to take since it's a simple nose drop, as opposed to something that requires a hospital visit.

Dr. Israelow says full-scale nasal vaccines are a logical next step as we look for new ways to fight the Pandemic.

"We're still playing catch up with SARS-CoV-2," says Dr. Israelow. "We think that mucosal route is the way to go that this this may help better stem the tide."

Clinical trials on humans are still more than a year away for these studies. Experts say traditional vaccines are still the best option while we wait.