Tattoo ink moves through the body, killing immune cells and weakening vaccine response

By Jason Gale

Bloomberg

Tattoo ink doesn’t just sit inertly in the skin. New research shows it moves rapidly into the lymphatic system, where it can persist for months, kill immune cells, and even disrupt how the body responds to vaccines.

Scientists in Switzerland used a mouse model to trace what happens after tattooing. Pigments drained into nearby lymph nodes within minutes and continued to accumulate for two months, triggering immune-cell death and sustained inflammation.

The ink also weakened the antibody response to Pfizer Inc. and BioNTech SE’s COVID vaccine when the shot was administered in tattooed skin. In contrast, the same inflammation appeared to boost responses to an inactivated flu vaccine.

The findings, published Nov. 25 in the Proceedings of the National Academy of Sciences, sharpen a public-health question as tattooing becomes mainstream. A 2023 Pew Research survey estimated that 32% of US adults have at least one tattoo, and 22% have multiple.

With billions spent on tattoos each year, the authors at Università della Svizzera italiana in Bellinzona say the results point to a need for tougher toxicology testing and stricter oversight of tattoo-ink ingredients, which face far looser regulation than medical products.

“This work represents the most extensive study to date regarding the effect of tattoo ink on the immune response and raises serious ...