Hate needles? You’ll soon be able to get vaccines via dental floss

Prepare for a new flossophy.

demonstrated a new purpose for the thin, flexible thread — delivering vaccines.

“This is extremely promising,” said North Carolina State University nanomedicine professor Harvinder Singh Gill, corresponding author of a new paper on the technique.

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Oral vaccination isn’t new. Vaccines to protect against rotavirus — which causes diarrheal disease — are given to infants as drops in the mouth. Vaccines can also be administered under the tongue or between the cheek and gums.

The new dental floss method utilizes the junctional epithelium, a highly specialized type of tissue located in the space between the tooth and the gums.

Unlike similar tissues, the junctional epithelium doesn’t function as a robust barrier. Its penetrable nature allows the passage of immune cells and antibodies to combat invaders.

“Because the junctional epithelium is more permeable than other epithelial tissues,” Gill explained, “it presents a unique opportunity for introducing vaccines to the body in a way that will stimulate enhanced antibody production across the body’s mucosal layers.”

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Vaccines induce the production of antibodies, which are key proteins that help the body fight off pathogens.

Injectable vaccines generate antibodies in the bloodstream, Gill said, but they tend to be less effective at producing antibodies on mucosal surfaces.

Mucosal surfaces are important entry points for many pathogens, such as influenza and COVID, and it’s crucial to have immune responses at these sites to prevent infection.

“We know that when a vaccine is given via the mucosal surface, antibodies are stimulated not only in the bloodstream, but also on mucosal surfaces,” Gill said.

“This improves the body’s ability to prevent infection, because there is an additional line of antibody defense before a pathogen enters the body.”

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For the study, researchers applied a peptide flu vaccine to unwaxed dental floss and flossed the teeth of lab mice.

They compared the antibody production in this approach to vaccines administered via the nose and under the tongue.

“We found that applying vaccine via the junctional epithelium produces far superior antibody response on mucosal surfaces than the current gold standard for vaccinating via the oral cavity, which involves placing vaccine under the tongue,” said Rohan Ingrole, first author of the paper and a former Ph.D. student under Gill at Texas Tech University.

“The flossing technique also provides comparable protection against flu virus as compared to the vaccine being given via the nasal epithelium.”

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Gill noted that vaccine delivery via the nose can be challenging.

Nasal mucosa acts as a barrier, preventing good absorption. And there’s a risk that the vaccine could bypass the blood-brain barrier and reach the brain, where it can pose problems.

Gill’s team reported that the dental floss system also worked for three other types of vaccines: proteins, inactivated viruses and mRNA. 

The immune response was the same even if the mice consumed food and water shortly after flossing.

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The researchers acknowledged that having someone else floss your teeth for you isn’t ideal, so they experimented with a floss pick.

They coated floss in the picks with fluorescent food dye and encouraged 27 people to deposit the dye into their epithelial junction.

“We found that approximately 60% of the dye was deposited in the gum pocket, which suggests that floss picks may be a practical vaccine delivery method to the epithelial junction,” Ingrole said.

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The findings were published last week in the journal Nature Biomedical Engineering.

The researchers plan on honing the flossing technique for humans and moving on to clinical trials.

There are already some potential drawbacks — it doesn’t work for those without teeth, like infants. And it’s unclear how effective it would be for people with gum disease or other oral infections.

Still, the team is optimistic.

“[The floss vaccine] would be easy to administer, and it addresses concerns many people have about being vaccinated with needles,” Gill said. “And we think this technique should be comparable in price to other vaccine delivery techniques.”