A fear of needles is a common reason for avoiding vaccines, even among many adults. Now US researchers have come up with a rather clever alternative: dental floss.
Led by a team from Texas Tech University, the researchers first identified an often overlooked surface in the mouth as an entry point for vaccines: the junctional epithelium (JE), which sits where the gums meet the teeth.
The JE is leaky by design, because it allows immune cells to move around and defend the oral cavity from bacterial attack. The researchers wondered whether this could also make this part of the mouth a suitable target for vaccines.
“We hypothesised that this leakiness of the JE could expedite the entry of vaccine antigens, and the abundance of immune cells in this microenvironment could elicit an adaptive immune response,” the researchers wrote in a paper published in Nature Biomedical Engineering.
Delivering medications to the JE is complicated by the tissue’s seclusion within the gumline, which is why it hasn’t really been considered as a potential location for introducing vaccines.
That’s where floss comes in, which is perfect for getting into tight spaces.
The researchers tested their hypothesis by coating dental floss with different types of vaccines and testing them on mice across a period of several weeks.
There were numerous encouraging indicators: strong immune responses were observed in the mouth and throughout the bodies of the mice, and the floss vaccine was effective in protecting mice against a later flu infection.
Further tests were conducted on human volunteers using dye rather than a vaccine, since clinical trials are still some way off. The amount of dye that reached the JE target via flossing was enough to suggest that this really could work in humans too.
“These findings establish floss-based vaccination as a simple, needle-free strategy that enhances vaccine delivery and immune activation compared with existing mucosal immunisation methods,” the researchers concluded.
