The National Institutes of Health (NIH) has suggested that vaccines delivered via dental floss could serve as a “promising” alternative to traditional injectable methods. The agency noted that while most vaccines are administered through needles, there is growing interest in needle-free options. An NIH-funded study indicates that dental floss might offer a practical and innovative approach, though further research is required to confirm its viability.

Previous studies have explored the mouth as a potential site for vaccine delivery, as mucosal tissues lining the body’s surfaces are common entry points for viruses. However, prior attempts to administer vaccines to areas like the cheeks or under the tongue have yielded inconsistent results. A new study led by Dr. Harvinder Singh Gill at North Carolina State University investigated delivering vaccines directly to the gums, focusing on the gingival sulcus—a small groove between teeth and gums. Researchers hypothesized that the junctional epithelium, a thin tissue in this area, could facilitate vaccine absorption due to its permeability.

In experiments with mice, scientists coated flat tape dental floss from a local pharmacy with various vaccine components, including peptides, proteins, and inactivated influenza viruses. The floss was used to clean the tiny teeth of lab mice, and the study found that these compounds successfully entered gum tissue. Vaccines containing the influenza virus triggered immune responses and antibody production in the animals. Immune activity was observed across multiple organs, with antibodies detected in both the bloodstream and mucosal surfaces.

The team tested whether the floss-based vaccine could protect mice from lethal influenza infections. The results showed full protection, with the method outperforming under-the-tongue delivery and matching nasal administration. Study co-author Rohan Ingrole highlighted that flossing achieved superior antibody responses on mucosal surfaces compared to current oral vaccination standards. Dr. Gill called the approach “extremely promising,” noting its potential to bypass limitations of nasal vaccine delivery.

The study, published in Nature Biomedical Engineering, demonstrated that floss-based vaccination could deliver proteins, inactivated viruses, peptides, and mRNA. In human trials, fluorescent dye applied via floss reached the gingival sulcus, suggesting clinical feasibility. Researchers concluded that this method offers a simple, needle-free strategy to enhance vaccine efficacy and immune activation compared to existing mucosal techniques.