Fifty percent of persons with HIV infection diagnosed in 2015 had been infected for at least 3 years, and a quarter had been infected for ≥7 years. Diagnosis delays varied substantially by population. Although the percentage of persons testing increased over time among groups at high risk, overall, 15% of persons were unaware of their infection. The prevalence of persons unaware of their infection varied among states, and half (50.5%) of persons with undiagnosed HIV infection in 2015 were living in the South. Gaps in testing remain, and missed opportunities for testing at health care visits are prevalent. Improved testing coverage and frequency are needed to meet the goal of at least 90% of persons living with HIV knowing their infection status and to reduce diagnosis delays and ultimately reduce HIV incidence in the United States (11).
Cultural factors (e.g., stigma, fear, discrimination, and homophobia) might contribute to longer diagnosis delays in some populations (12). Asians accounted for the highest percentage of persons living with undiagnosed HIV infection compared with all other race/ethnicity groups (13). Although blacks were more likely than whites to report testing in the past 12 months across all groups at risk, the median diagnosis delay was 1 year longer for blacks (median = 3.3 years) than for whites (median = 2.2 years). The testing results might reflect national efforts to improve access to testing among blacks, and black MSM in particular, through prevention programs and media campaigns. In 2007, CDC launched the Expanded Testing Initiative (https://www.cdc.gov/hiv/policies/eti.html) to facilitate HIV diagnosis and linkage to care among blacks and continues to support high levels of testing. CDC’s MSM Testing Initiative (https://www.researchgate.net/publication/287201580) scaled up HIV testing and linkage-to-care activities among black and Hispanic or Latino MSM in 11 cities. In addition, CDC implemented Testing Makes Us Stronger (https://www.cdc.gov/actagainstaids/campaigns/tmus), a public education campaign to increase testing among black MSM, from 2011 to 2015.
The longer diagnosis delay among non-white racial/ethnic groups might partly reflect the higher proportion of infections attributable to heterosexual contact among these groups compared with whites (14), given that heterosexual persons had longer diagnosis delays. Among all transmission categories, males with infection attributed to heterosexual contact had the longest median diagnosis delay (4.9 years). This observation was consistent with the finding that heterosexual males at increased risk for infection were less likely to report testing in the past 12 months than were heterosexual females at increased risk. Heterosexual men are less likely to visit a health care provider than are both women and MSM, leading to fewer opportunities for testing (15). Moreover, compared with other risk groups, heterosexual persons at increased risk were less likely to have been offered an HIV test even when visiting a health care provider in the past 12 months, possibly because of low perceived risk for infection (15,16). This finding highlights the importance of implementing routine screening in health care settings.
A previous estimate¶ of diagnosis delays among persons who received a diagnosis of HIV infection in 2011 indicated that half had been infected for 3.6 years. The median diagnosis delay of 3.0 years among HIV diagnoses in 2015 reflects an absolute reduction of 0.6 years (7 months) and a relative reduction of 17%, representing a considerable decrease over a 4-year period (8). Earlier detection of HIV combined with prompt linkage to care and initiation of antiretroviral treatment enhances preservation of immune function and, if viral suppression is achieved and maintained, reduces risk for sexual transmission of HIV (4). In addition, persons who know they have HIV infection substantially reduce their HIV-related risk behaviors: the prevalence of unprotected anal or vaginal intercourse was found to be 53% lower among persons aware of their HIV status than among those who were unaware of their status (17).
For HIV treatment to be effective in reducing HIV incidence, infections need to be diagnosed as quickly as possible. This requires increasing HIV testing coverage and frequency. CDC recommends testing all persons aged 13–64 years at least once as a routine part of medical care and more frequent testing (at least annually) for persons at high risk for HIV infection (7). A large proportion (84%) of HIV sexually transmitted from MSM and heterosexual persons is transmitted by MSM (1). Some sexually active MSM might benefit from more frequent testing (e.g., every 3 to 6 months) (18). Testing according to CDC guidelines is critical to diagnosing HIV infection, so that anyone who receives a diagnosis of HIV infection can start antiretroviral treatment. Overall, prior year testing increased among groups at high risk over time. However, 29% of MSM (in 2014), 42% of persons who inject drugs (in 2015), and 59% of heterosexual persons at increased risk (in 2016) did not report testing in the past 12 months. In addition, it is important to note that these data are from persons residing in large metropolitan statistical areas in the United States. Studies have found that persons residing in rural areas are less likely to report prior HIV testing, including in the past 12 months, compared with their urban counterparts, and that persons living in rural areas are more likely to have HIV infection diagnosed at a late stage (19,20). Barriers to implementing routine testing include lack of time, competing priorities, and concerns about reimbursement on the health care provider’s part and stigma and lack of perceived risk on the client’s part (21). Lack of perceived risk was also one of the main reasons cited by MSM in NHBS for not testing in the past 12 months.
A recent analysis of HIV testing frequency using NHBS data indicated that among persons at high risk for HIV infection who were ever tested, the estimated average interval between two successive HIV tests decreased from 10.5 months (2009) to 7.7 months (2014) among MSM, from 14.4 months (2009) to 11.5 months (2015) among persons who inject drugs, and from 21.1 months (2010) to 19.9 months (2013) among heterosexual persons at increased risk for HIV acquisition (22). Although the decreases in testing intervals are encouraging and indicate that, on average, MSM and persons who inject drugs are meeting recommendations for annual testing, these data are among persons already testing. Limited data suggest that MSM who have never been tested for HIV might engage in higher risk behaviors than do MSM who have been previously tested. One study found that MSM who had never been tested were 1.46 times as likely (95% confidence interval = 1.17–1.81) to report condomless anal sex in the past 3 months with an HIV-positive or serostatus-unknown partner than were persons who tested previously (23).
The findings in this report are subject to at least four limitations. First, missing CD4 test results could be caused by either incomplete reporting or not having had a CD4 test done. However, 89.4% of persons with HIV infection diagnosed in 2015 had a first CD4 test after diagnosis reported by June 2017. Second, adjustment for missing risk factors might be inaccurate if factors associated with these were not accounted for in the model. Third, NHBS is not a nationally representative sample, so results are not generalizable to all cities or to all groups at high risk in participating cities. Finally, behavioral data are self-reported and subject to social desirability bias.
The interval from HIV infection to diagnosis has decreased in recent years, but diagnosis delays continue to be substantial for some population segments. Whereas testing in the past 12 months has increased in recent years among groups at high risk, a high proportion of persons in all risk groups remain untested, with many missed opportunities for testing. Diagnosis delays lead to missed opportunities for HIV care and treatment and prolong the time a person is unaware of their infection, increasing the potential for HIV transmission. For care and treatment to reduce HIV incidence effectively, a high proportion of cases need to be diagnosed and treated soon after infection occurs. Continued efforts to determine why cases are not being diagnosed soon after infection and to assure implementation of routine and targeted testing can help reduce both the number of persons unaware of their infection and diagnosis delays.