Could Dental Floss One Day Deliver Your Flu Vaccine?

A study published in Nature Biomedical Engineering on July 22, 2025, is raising eyebrows in both dentistry and immunology circles.

Researchers demonstrated a novel vaccine delivery method in an animal model, using dental floss to introduce a vaccine via the tissue between the teeth and gums.

The work comes from a team led by Harvinder Singh Gill at North Carolina State University and Texas Tech University.

The key to the approach is a thin strip of tissue at the base of the gum pocket called the junctional epithelium.

The junctional epithelium is leakier, or more permeable, than other tissues, which led the researchers to think it might be possible to deliver an effective immune-boosting vaccine there using dental floss.

Testing found that the new technique stimulates the production of antibodies in mucosal surfaces, such as the lining of the nose and lungs

— the very surfaces where respiratory viruses tend to gain entry.

In laboratory mice, applying a flu vaccine to unwaxed dental floss and then flossing the teeth produced a strong immune response.

Using dental floss on mice to apply a flu vaccine triggered a robust immune response — better than existing oral approaches and comparable to nasal vaccines, but without the risks.

It also worked with mRNA and protein-based vaccines.

The team also ran a small human test:

in a trial with 27 volunteers, floss picks coated with fluorescent dye deposited about 60% of the dose into gum pockets.

The researchers are quick to note that significant development work remains before anything like this could reach a clinic.

They are now developing new flossing tools to improve accuracy and ensure people receive a consistent dose, with the longer-term aim of allowing individuals to self-administer vaccines at home.

For now, the finding adds an unexpected dimension to a habit dentists have long encouraged — and hints that the humble space between your teeth and gums may be more medically significant than most patients realize.