As scientific advances continue, the fear of needles might no longer stand in the way of getting vaccines without fuss, thanks to scientists who have created and tested a novel vaccine delivery system using dental floss.

Indeed, using dental floss to introduce the vaccine through the tissue between the teeth and gums is the topic of the new paper called ‘Floss-based vaccination targets the gingival sulcus for mucosal and systemic immunization,’ published in the journal Nature Biomedical Engineering.

In the words of Harvinder Singh Gill, corresponding author of a paper on the work and the Ronald B. and Cynthia J. McNeill Term Professor in Nanomedicine at North Carolina State University, mucosal surfaces are a source of entry for pathogens like influenza and COVID.

Injected vs. dental floss vaccine

Currently, however, the traditional injection-based vaccines primarily produce antibodies in the bloodstream and relatively few on mucosal surfaces. Giving a vaccine via the mucosal surface stimulates antibodies not only in the bloodstream but also on mucosal surfaces.

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

Specifically, our bodies’ junctional epithelium, a thin layer of tissue in the deepest part of the pocket between the tooth and the gum, lacks the barrier features found in other epithelial tissues. This allows it to release immune cells to fight bacteria. As Gill explained:

“Because the junctional epithelium is more permeable than other epithelial tissues – and is a mucosal layer – 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.”

And the results of testing the vaccine applied on the teeth of lab mice via unwaxed dental floss indicate the researchers were correct. Notably, they found a far superior antibody response than even the previously accepted method of oral vaccination that involves placing the vaccine under the tongue, as well as the nasal application that in itself carries certain risks.

That said, an ideal way of applying the vaccine in humans is with a floss pick – a piece of floss between two prongs that a user can hold by the handle, instead of having to hold vaccine-coated floss in their fingers. 

However, applying vaccines via dental floss wouldn’t work on infants and toddlers who do not yet have teeth, and more research is necessary to understand how or whether this approach would work for people with gum disease or other oral infections.

Meanwhile, scientists around the world are testing other ways to apply the COVID-19 vaccine, including in Canada, where a next-generation inhaled vaccine started a phase-2 clinical trial in March. 

Additionally, the European Commission has granted approval for the first ‘self-amplifying’ mRNA COVID-19 vaccine, although a study has revealed that mRNA vaccines could be dangerous to unborn babies.