The last decade has seen rising rates of methamphetamine injection among injection drug users (IDUs) in King County, Washington, which includes Seattle. While currently women and heterosexual men IDUs in the county have a low HIV rate, their sharing of injection equipment with men who have sex with men (MSM) could provide an opportunity for the virus to spread more rapidly among them.

Researchers analyzed data from two serial cross-sectional surveys of IDUs in King County. These included 2005 to 2015 data on 2,103 IDUs from four National HIV Behavioral Surveillance (NHBS) surveys as well as 2004 to 2015 data from five behavioral surveys that the Public Health–Seattle and King County Needle Exchange conducted with 1,964 local needle exchange clients. They restricted their findings to IDUs who reported any sex within the past year and broke down their results into the categories MSM, men who have sex with women (MSW) and women.

Sara Glick, PhD, MPH, of the University of Washington, presented findings at the 2017 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle. 

Sara Glick of the University of Washington at CROI 2017 in Seattle Ben Ryan

The researchers found that, according to both surveys analyzed, King County IDUs reported injecting meth at rising rates over the past decade. The NHBS  and King County surveys showed that among women, a respective 26 percent and 25 percent reported injecting meth in 2005, figures that rose to 65 percent and 61 percent in 2015. The corresponding respective figures for MSM were 55 percent and 76 percent in 2005 and 88 percent and 83 percent in 2015; for MSW they were 42 percent and 16 percent in 2005 and 69 percent and 57 percent in 2015.

Most of the increase in injection use of meth was attributed to the rising popularity of mixing heroin with meth for injection, known as a “goofball.”

According to the NHBS surveys, the majority of King County IDU respondents reported sharing drug injection equipment during the past year, including 54 percent of MSM, 73 percent of MSW and 78 percent of women. Seven percent of MSW and 15 percent of women reported sharing injection equipment with someone who was likely an MSM during the previous year. Meanwhile, 54 percent of MSM meth injectors who reported sharing injection equipment did so with an MSW or woman (mostly the latter).

The findings about injection equipment sharing between MSM and non-MSM are particularly concerning because about 35 to 40 percent of meth-using MSM in King County have HIV. Currently, non-MSM who inject meth have a low HIV prevalence. HIV could thus begin to jump from the MSM population to MSW and women who inject meth and spread more widely among them.

Glick attributes the low HIV rate among IDUs in King County to robust prevention efforts, including the use of syringe services programs.