HCV Serosorting

Testing, Testing
Serosorting is common for IV drug users who know their HCV status
by Larry Buhl

A new study shows IV drug users who know they carry the hepatitis C virus are likely to consider their serostatus when deciding whether and with whom to share injection equipment.

The results, published in the December 15, 2013 Journal of Infectious Diseases showed that people who inject drugs (PWID) and test positive for the hepatitis C virus (HCV) are more likely to share syringes and injection equipment with others who are also infected, and less likely to do so with people who are HCV-negative or unknown—the equivalent of sexual “serosorting.”

Serosorting is a widely used strategy for reducing the spread of HIV as well. The idea is that by having sex only with partners of the same serostatus or making decisions about sexual activities or positions on that status, the risk or transmission will be much lower. The data also bear this out.

The HCV study, led by Bryce Smith, Lead Health Scientist at the U.S. Centers for Disease Control and Prevention (CDC) Division of Viral Hepatitis, used data from the 2009 National HIV Behavioral Surveillance System-Injection Drug Users to see whether serosorting was occurring among people who inject drugs.

The analysis included 9,690 injection drug users in twenty major cities across the U.S. who were asked to report their own hepatitis C status and that of the person with whom they last shared injection equipment within the past twelve months. HCV testing of participants and partners was not done in this study. Seventy-two percent were men, forty-seven percent were black, twenty-two percent were Hispanic/Latino, and twenty-seven percent were white. Nearly sixty percent were unemployed; sixty-one percent had ever been homeless.

The results:

• Seventy-five percent of study participants said that they knew their HCV status.

• Fifty-seven percent of participants who knew their status reported that they were HCV-positive.

• Forty-seven percent reported sharing equipment with their last injecting partner.

• Thirty-eight percent of these said they knew the HCV status of their last equipment-sharing partner.

• People who knew they were HCV-positive were about four times more likely to know their last partner’s status.

• People who knew they were HCV-negative were more than twice as likely to know their last partner’s status.

• Participants who reported being HCV-positive were nearly five times more likely to share injection equipment with partners who were also HCV-positive.

Smith’s study is the first major piece of research on a national level to show that PWIDs use their serostatus to make decisions about needle sharing.

In an accompanying editorial in the Journal of Infectious Diseases, Dr. Arthur Kim from Massachusetts General Hospital and Kimberly Page from the University of California at San Francisco praised the study but noted that the population in the study differed from those who are now most at risk of contracting HCV through IV drug use.

Speaking with A&U, Dr. Kim expounds on his comments, saying that IV use, and, not coincidentally HCV, have become an “exurban” issue rather than an urban one. “What we know is that heroin use among young people is now primarily suburban and rural and affects mainly whites, and that people of color tend to avoid it now, although that was not the case in the past. Anecdotally what we see here around Boston is that teens and young adults find oral opiates too expensive, so they switch to heroin and put themselves at great risk for hepatitis.”

Still, Kim acknowledges that the study is groundbreaking for clearly showing that testing does alter behavior. “We already knew that testing was important, but now we have another reason why people should be tested [for HCV],” he tells A&U.

The study authors admit that HCV-infected PWIDs serosorting strategy will be effective in preventing the spread of HCV, “only if testing is both accurate and comprehensive, then accompanied by counseling that is truly informative of those at risk of and with infection, and finally followed by linkage to treatment.”

Dr. Kim agrees with this strongly, and told A&U that we need further research to know exactly how counseling for PWIDs who test positive might affect their willingness to share their serostatus with other IV drug users.

“As with all testing, and as we learned with HIV, pre- and post-test counseling is important to understand the implications of testing positive. What we also know is that IV drug users are less likely to get that counseling. It could be because they feel that hepatitis is inevitable to them if they keep using heroin, but we need data before we conclude this.”

Both Kim and the researchers agree that curbing the spread of HCV requires more testing, not only to find individuals who are infected with HCV, but also to learn their attitudes and behaviors on a larger scale.

Larry Buhl is a radio news reporter, screenwriter, and novelist living in Los Angeles. His young adult novel, The Genius of Little Things, debuted in January 2013.