Humans have been tattooing their skin for thousands of years, and the practice has grown in popularity across the world in recent decades. However, tattoos don’t come without risks to our health and immune systems, experts say. The risk of contracting an infection or disease via unsanitary or cross-contaminated tattoo needles is well documented, but those risks have declined over time as more sophisticated hygiene standards have been implemented globally. Less is known, however, about the long-