The findings of this study suggest that IDUs in Puerto Rico have a very high rate of infection with HCV. The rate of HCV infection found in this study (89.0%) is higher than that reported in countries considered to have among the highest rates around the world.2–4,21–23
Moreover, HCV infection in our sample appears to have been acquired very shortly upon initiation of drug injection. We found HCV seroprevalence to exceed 75% among IDUs who had been injecting for a period of 1 year or less. Rapid increases in HCV seroprevalence as a function of years of injection have been reported elsewhere,4,24–27
although the baseline rates and the slopes of the curves reported have generally been lower than in our case. These findings are consistent with some of our previous studies reporting higher overall HIV risk behaviors, particularly the use of shooting galleries.28,29
Use of shooting galleries appeared to be of particularly high risk for HCV infection. Several studies have documented that attending shooting galleries is a high risk behavior for the transmission of HIV30–34
especially among Puerto Rican IDUs.28
Based on these findings, Puerto Rican IDUs who use shooting galleries should be educated on the necessity of using clean injecting equipment and on how to clean it properly in order to arrest this emerging epidemic of HCV.
We also found a strong association between having had a tattoo while incarcerated and HCV infection. Since tattooing in jail or prison is commonly performed using non-sterile equipment,35
it is not surprising that this practice would be a risk factor for the transmission of blood borne pathogens. A similar association has been reported in a study conducted among IDUs in Spain.36
Several authors have discussed tattooing as a mode of HCV and HIV transmission.37–39
Other studies have noted a high prevalence of tattoos among anti-HCV positive patients with chronic hepatic disease40
and among persons attending HIV outpatient clinics. Moreover, a study among fishermen in Thailand found a significant association between HIV seroprevalence and having had a tattoo.41
However, in the United States case control studies have generally reported no association between HCV and tattooing.42,43
Inconsistent findings could be reflecting variations in the sanitary conditions under which tattoos are made across countries.
In this study we found that sex with a casual or commercial sex partner without using condoms was not associated with HCV infection. In contrast, history of sexually transmitted diseases was associated with HCV infection. Other studies have also found sexual practices to be unrelated to HCV infection43
and a history of sexually transmitted diseases to be associated with HCV infection.42,44
Prevention of HCV spread in the IDU population should thus include harm reduction measures and information on safer sex practices for both IDUs and their sexual partners.
Some of the limitations of this study merit comment. The sample in our study cannot be considered representative of the population of IDUs in Puerto Rico. However, our recruitment procedures were designed to reduce selection biases to the greatest extent possible. More importantly, the study had a cross-sectional design and the temporal sequencing of risk behaviors and HCV infection cannot be established.
Because a vaccine for HCV is unlikely to be developed in the near future, prisons and drug abuse treatment programs in Puerto Rico might play an essential role in controlling the epidemic among drug users. Health care institutions in Puerto Rico will need to intensify their efforts to reduce the risk of HCV transmission among drug injectors and to help those already infected obtain the care they need. Furthermore, prisons and drug treatment programs will also need to develop and expand linkages with the health care system for HCV prevention screening and referral to care so that their inmates and patients can maintain their health to the greatest extent possible.