During 2001–2006, new human immunodeficiency virus (HIV) diagnoses among black men aged 13–24 years who have sex with men (MSM) in 33 states increased by 93% (1).
The Wisconsin Division of Public Health (WDPH) recently reported to CDC a 144% increase during 2000–2008 in HIV diagnoses among black MSM aged 15–29 years in Milwaukee County.
In October 2009, the City of Milwaukee Health Department (MHD), WDPH, and CDC investigated whether the increase in HIV infections among young black MSM in Milwaukee represented increased HIV transmission or simply better identification of prevalent infections.
This report describes the results of that investigation, which indicated that a new “social networks” HIV testing strategy and the recent expansion of better targeted HIV testing efforts accounted for few diagnoses among young black MSM and occurred after HIV diagnoses increased, respectively. Therefore, although some diagnoses were made because of intensified testing, an increase in HIV transmission likely occurred.
Moreover, an increase in syphilis diagnoses among young black MSM in Milwaukee preceded the increase in HIV diagnoses, which suggests that changes in risk behavior or sexual networks might explain the increase.
These findings highlight the need for new or improved interventions promoting prevention education, early HIV detection, and entry to care for young HIV-infected and at-risk black MSM in Milwaukee.
CDC, MHD, and WDPH reviewed the timing of recently implemented HIV testing strategies and examined data from two sources: 1) name-based, confidential HIV surveillance data (collected in Wisconsin since 1985) and 2) HIV testing data from publicly funded test sites.
HIV diagnoses that were not reported previously were considered new diagnoses.
rends were analyzed comparing the number of new HIV diagnoses (counted by year in which the diagnosis was made), number of tests performed in publicly funded test sites, and the proportion of those tests that were positive among black and nonblack (white and Hispanic) MSM, stratified by age group (15–19, 20–24, 25–29, and ≥30 years).
Because of small numbers, year-to-year differences were highly variable, so CDC compared aggregate data for the years 1999–2001 (before diagnoses increased and before new testing strategies were adopted) and 2006–2008 (after diagnoses increased and after new testing strategies were adopted). WDPH determined whether the new social networks testing strategy or traditional testing strategies were associated with cases identified.
The trends in HIV diagnoses also were compared with trends in diagnoses of primary or secondary syphilis in young black MSM in Milwaukee because HIV and syphilis are both transmitted through unprotected sex.
Primary and secondary syphilis occur within a few months of infection, so increases in primary and secondary syphilis suggest increases in HIV incidence also might have occurred. CDC compared primary and secondary syphilis incidence for 1999–2001 and 2006–2008 using WDPH surveillance data.
Because syphilis surveillance data in Milwaukee do not document HIV coinfection, CDC also reviewed MHD partner services records, in which coinfection is recorded routinely, for all primary and secondary syphilis cases among black MSM aged 15–29 years diagnosed during January 2006–June 2009.
The latter period was chosen to maximize the number of cases considered (the period for trend analyses ended in 2008 because of concerns about delayed reporting of more recent diagnoses to surveillance).
During 2006–2008, WDPH intensified HIV testing statewide. Beginning in 2006, a new social networks testing strategy encouraged MSM who were diagnosed recently with HIV to recruit MSM within their social networks for HIV testing. In 2007, WDPH intensified targeted HIV testing to black MSM by urging publicly funded test sites trained in the social networks testing strategy to administer ≥45% of all tests to black and Hispanic MSM. The extent to which these strategies detected infections among previously undiagnosed black MSM was unclear.
Comparing 1999–2001 and 2006–2008, new HIV diagnoses increased among black MSM aged 15–19, 20–24, and 25–29 years (by 143%, 245%, and 78%, respectively) (Table). In contrast, new diagnoses increased less among nonblack MSM aged 20–24 years (by 14%) and 25–29 years (by 45%),* and they decreased among black and nonblack MSM aged ≥30 years (by 40% and 1%, respectively). Comparing 1999–2001 and 2006–2008, the percentage increase in the number of HIV tests among young black MSM aged 15–19, 20–24, and 25–29 years ranged from 90% to 372%, whereas the percentage increase in the number of HIV tests among nonblack MSM in each of these age groups ranged from 44% to 63%.
Reported by P Biedrzycki, MPH, City of Milwaukee Health Dept; J Vergeront, MD, M Gasiorowicz, MA, Wisconsin Div of Public Health. J Bertolli, PhD, A Oster, MD, PS Spikes, PhD, T Sanchez, DVM, Div of HIV/AIDS Prevention; TA Peterman, MD, Div of STD Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention; DC Ham, MD, CDC Experience Applied Epidemiology Fellowship; WL Jeffries IV, PhD, EA Torrone, PhD, CF Nielsen, PhD, EIS officers, CDC.