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HIV increase in black men not a surveillance artifact
Increased testing does not account for case surge
HIV diagnoses among young black men who have sex with men (MSM) have increased recently in the United States; possible explanations include expanded HIV testing or increased HIV transmission. However, expanded HIV testing did not account for increased HIV diagnoses that occurred among young black MSM in Milwaukee County, WI from 1999–2001 to 2006–2008 increased transmission likely occurred, the Centers for Disease Control and Prevention (CDC) reports.1
"New or improved interventions to reduce HIV risk and increase HIV testing and care for those found to be infected among young black MSM are needed," the CDC concluded.
During 2001–2006, new HIV diagnoses among black MSM aged 13–24 years in 33 states increased by 93%. 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.
The subsequent investigation 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.
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). 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%. Along with the increased number of tests conducted, increased HIV positivity among black MSM aged 15–19 and 20–24 years and nonblack MSM aged 25–29 years also contributed to the trend of increasing diagnoses in these groups.
"Increases in both HIV and syphilis diagnoses were confirmed among young black MSM in Milwaukee County during 1999–2008," the CDC reported. "More complete ascertainment of prevalent infection among young black MSM likely was aided by the expansion and improved targeting of HIV testing that occurred in Milwaukee County during the period of observation. However, expanded and better targeted testing began after HIV diagnoses and positivity began to increase and, therefore, could not have accounted for the observed increase."
Further, if increased testing primarily identified MSM who had been HIV-infected but undiagnosed for a number of years, an increase in diagnoses mainly in older MSM would have been expected. Instead, diagnoses were observed to have decreased among black MSM aged ≥ 30 years, and both diagnoses and positivity increased among black MSM aged 15–19 years. Moreover, the proportion of all black MSM HIV diagnoses accounted for by MSM aged 15–19 years increased from 8% to 16% from 1999–2001 to 2006–2008, but nonblack MSM aged 15–19 years accounted for < 5% of nonblack MSM HIV diagnoses during both periods. Assuming that sexual exposure to HIV has had less time to occur in the 15–19 year age group than in any other age group, diagnoses in this group are more likely to represent recent infection.