NEW YORK - If you're planning on getting a tattoo, make sure it's from a professional and not your friend, says a new report from the Centers for Disease Control and Prevention (CDC).
In an analysis of several dozen past studies, CDC researchers found that tattoos from non-professionals appear to carry a risk of the blood-borne liver infection hepatitis C. That included tattoos done by friends or family, or ones done in prison.
On the other hand, there was no evidence that tattoos done by professionals carried a hepatitis C risk.
Hepatitis C is passed through contact with infected blood. In the US, there are roughly 18,000 new infections each year, most of which occur when people who inject heroin and similar drugs share tainted needles or syringes.
But in almost 20 per cent of acute hepatitis C infections, the person has no known risk factor, said Dr. Rania A. Tohme, a medical epidemiologist at the CDC who led the new study.
Given that -- and the popularity of tattoos -- there have been concerns that the body art could be a risk factor for hepatitis C.
Based on these findings, it's the tattoos from non-pros that consumers should beware, according to Tohme.
"Tattoos and piercings can transmit hepatitis C and other infections if performed under non-sterile conditions," Tohme told Reuters Health in an email. "People should not have tattoos or piercings done by friends or by people who are not trained professionals."
The findings, published in the journal Clinical Infectious Diseases, are based on a collection of studies published since 1994.
In general, people who had tattoos done by non-professionals faced a hepatitis C risk that was two to four times higher than average.
Prison tattoos are a particular concern, Tohme's team writes, because tattooing is so common, and many prisoners may have other risk factors for hepatitis C. And outbreaks of the infection have been linked to tattooing among prisoners.
But no US outbreaks have been tied to professional tattoo parlors.
"To this date, there has been no evidence that tattoos and piercings performed in professional parlors in the United States have been implicated in transmission of hepatitis C virus," Tohme said.
Still, you can take some precautions if you're thinking of inking up.
Tohme said to make sure the tattoo artist is using sterile equipment, including single-use needles and ink that has not been used on anyone else.
"Disposable piercing needles, tattoo needles and razors are used on one person and then thrown away. Reusing needles or razors is not safe," Tohme said.
In the US, new cases of hepatitis C infection have fallen sharply since the 1980s, according to the CDC.
But chronic hepatitis C infection remains a major public health problem, the agency says.
Between 75 per cent and 85 per cent of people infected with hepatitis C develop chronic infection, which can eventually cause serious liver diseases like cirrhosis (scarring of the liver) and liver cancer.
An estimated 3.2 million Americans have chronic hepatitis C, about half of whom are unaware of it. (The initial infection most often causes no symptoms.)
There are medications for treating chronic hepatitis C, though they are not effective for everyone and have side effects like fatigue, nausea, headache and sleep problems.