Tattooing could be responsible for more cases of hepatitis C virus infection (HCV) in the US than previously thought, according to a study in the May 12th edition of the Archives of Internal Medicine. The investigators suggest that US public health guidelines should be changed to recognise tattooing as a common mode of HCV transmission, and that commercial tattoo parlours are inspected and regulated to control the spread of HCV.
There is conflicting evidence about the role of tattooing in HCV transmission. Although some small studies have found that tattooing was the likely source of chronic HCV infection and acute hepatitis, the US Sentinel Counties Study of Viral Hepatitis, which looked at risk factors for HCV in people with an acute hepatitis did not find tattooing to be a major risk factor for HCV.. However, several studies have found that many patients with chronic HCV without symptoms (subclinical) report tattooing as their only HCV risk. Investigators term this “the tattooing paradox.”
Investigators from Texas postulated that tattooing may only involve the transmission of small amounts of HCV into the skin, in sufficient quantity to result in subclinical infection, but not enough to cause an acute illness. By contrast, injecting drug use involves the injection of large amounts of HCV directly into the blood and is likely to cause both an acute illness shortly after infection as well as chronic infection.
The results of a 1991 study involving 627 patients with spinal disorders who were tests for HCV were reanalysed. At baseline all the patients were unaware of their HCV status and were interviewed by a junior doctor about possible risk factors for HCV, including injecting drug use and tattooing. A total of 43 patients tested positive for HCV antibodies, and 48 patients reported some form of acute hepatitis in the past. Forty patients reported injected drug use as a risk behaviour and 52 patients had been tattooed in a commercial tattoo parlour.
When the results were controlled for other possible risk factors for HCV transmission, including working in healthcare and multiple sexual partners, the investigators found that a history of injecting drug use was strong linked with having acute hepatitis (HR 5.8, 95% CI, 2.5 – 13.8) and HCV HR 7.2, 95% CI, 3.1 –16.5) . Tattooing was found to be strongly linked to having chronic hepatitis C (HR6.5 95% CI, 2.9 – 14.4) but not having had an acute episode of hepatitis (HR 1.2, 95% CI, 0.5 – 3.3).
The investigators suggest that their findings solve “the tattooing paradox”. As tattooing involves only subdermal exposure to small amounts of HCV it is unlikely to cause the kind of clinical symptoms looked for in the US Sentinel Study. In addition, the Sentinel study discounts tattooing as a mode of HCV transmission if a patient has other factors perceived to be of greater risk including injecting drugs or sex between men.
The investigators call for the inspection and regulation of commercial tattoo parlours (such regulation already exists in the UK and western Europe).
Further information on this website
Hepatitis C - overview
Hepatitis C - factsheet
HIV and hepatitis - booklet in the information for HIV-positive people series (pdf)
Haley RW et al. The tattooing paradox: Are studies of acute hepatitis adequate to identify routes of transmission of subclinical hepatitis C infection? Annals of Internal Medicine, 165: 1095 – 1098, 2003.