BACKGROUND: Substantial evidence supports the link between equipment used to inject drugs and transmission of the hepatitis C (HCV) and human immunodeficiency viruses (HIV). In 2015, HIV spread rapidly within a network of people who injected drugs in rural Indiana, over 90% of whom were co-infected with HCV. Active surveillance for: 1) acute or recent HCV infection, 2) HIV care status, and 3) HIV viral load among people living with HIV may help identify individuals at risk for HIV transmission by injection drug use (IDU).
METHODS: During May 1, 2015 – June 30, 2016, Wisconsin HIV and HCV registries were linked monthly by a SAS deterministic program. A monthly report included the number of HIV cases with a transmission category of IDU and the number of new co-infections, defined as a prevalent HCV or HIV case with a new report of HCV or HIV infection. A monthly person-level report included dates of infection, demographics and behavioral risks at time of report. An algorithm was used by surveillance staff to review HCV and HIV registries and HIV laboratory reports, and work with HIV Partner Services to prioritize follow-up of individuals at risk for transmitting HIV via IDU.
RESULTS: During the surveillance period, 272 HIV and 4,407 HCV cases were newly reported. HIV infections with a transmission category of IDU were elevated (above a 5-year average) in May, 2015, only, and HIV-HCV co-infections were elevated from May to August, 2015. The monthly match identified a total of 63 new HIV-HCV co-infections. The most recent identified infection was HCV in 51 (81.0%), HIV in six (9.5%) and six (9.5%) were diagnosed simultaneously. Risk was complete for 21 (33.3%), of which six (28.6%) indicated recent (within 12 months) IDU. Of the six with recent IDU, three were HIV virally suppressed and thus unlikely to transmit HIV and three were found to be out of HIV care or HIV virally unsuppressed and were recommended for reassignment to HIV Partner Services.
CONCLUSIONS: Routine linkage of state HIV and HCV registries allowed the Wisconsin AIDS/HIV and HCV Programs to monitor for an increase in HIV transmission associated with reported IDU as well as for recent HIV among people with HCV infection. Incomplete risk data at time of HCV report was a barrier to assessing IDU risk. This activity provides an opportunity for individuals at risk for HIV transmission or poor health outcomes to be identified and linked to care.