Researchers successfully test needleless vaccination using dental floss

Researchers have developed a special kind of floss that can deliver vaccines through the gums, a method that could one day offer a needle-free alternative for vaccination. The research, published yesterday in Nature Biomedical Engineering, demonstrates a new way to trigger a protective immune response using a common dental hygiene tool.

The project's senior author, Harvinder Gill, said the idea came to him after reading that the pockets of gum between the teeth — the gingival sulcus — are exceptionally good at absorbing molecules. This inspired his team to test if this permeable area could be a new entry point for vaccines.

The researchers put their theory to the test in a study on mice. They coated dental floss with inactive flu virus and flossed a group of 50 mice every two weeks for a total of three doses. Four weeks later, the team exposed those mice to a live flu virus. The results were definitive — all the mice that received the floss-based vaccine survived, while all the unvaccinated mice died. The flossed mice showed a robust and systemic immune response, with elevated levels of antibodies and T cells in their lungs and spleens.

To evaluate the potential in a clinical setting, the team also conducted a feasibility test with 27 human volunteers. The participants used dental floss picks coated with food dye and successfully delivered, on average, 60% of the dye to their gums. A subsequent survey found that most volunteers would be open to trying a floss-based vaccine and would prefer it over a traditional shot. The researchers noted that clinical trials are needed to prove the concept is viable for human use.