Your Mouth Has a Virome — and Researchers Are Just Beginning to Map It

Most people have heard of the oral microbiome — the bacteria that live in the mouth and influence everything from cavities to heart health. But there is a far less understood community sharing that same space: the virome, the collection of all viruses that inhabit the human body. Scientists estimate the body hosts roughly 380 trillion viruses, which is actually greater in number than the bacteria present, yet very little is known about what a "healthy" virome even looks like.

A new review article published as the cover story of the October 2026 issue of the Journal of the American Dental Association (JADA) takes a close look at this emerging frontier. Researchers from the UCLA School of Dentistry examined what is currently understood about the oral virome and its connections along what scientists call the oral-gut-brain axis — the biological pathways linking the mouth, the digestive system, and the brain. The study also outlines the significant gaps in current knowledge and the challenges involved in studying viral communities inside the body.

The research comes out of a newly established Human Virome Characterization Center at UCLA, one of only five such centers in the United States created under the NIH's Human Virome Program. The UCLA center received a $20.6 million grant from the NIH — the largest ever awarded to the UCLA School of Dentistry — and is notably the only one of the five centers based at a dental school. Investigators there are working to define what a healthy human virome looks like across different life stages and in diverse populations.

For patients, the practical takeaways are still some years away, but the direction of the research is meaningful. Understanding how viral communities in the mouth relate to disease, immune response, and systemic health could eventually help dentists and physicians detect problems earlier, personalize treatment, and better predict oral health risks over time.