SUMMARY Background Transgender women (TGW) are among the groups at highest risk for HIV infection, with a prevalence of 27.7% in the United States, but despite this high risk, TGW have documented high rates of undiagnosed HIV infection. We propose that this disparity can be addressed by characterizing TGW in a molecular transmission network to prioritize public health activities. Methods Since 2006, HIV pol sequences from drug resistance testing have been reported to Los Angeles County (LAC) Department of Public Health and linked to demographic data, gender, and HIV transmission risk factor data for each case in the enhanced HIV/AIDS Reporting System (eHARS). We reconstructed a molecular transmission network using HIV-TRACE (pairwise genetic distance threshold of 0.015 substitutions/site) from the earliest pol sequences from 22,398 unique individuals, including 412 (2%) self-identified TGW. We examined the possible predictors of clustering using multivariate logistic regression. We characterized the genetically-linked partners of TGW and calculated assortativity—the tendency for persons to link to other persons with the same attributes—for each transmission risk group. Findings We found that 36% of individuals (8,133/22,398) clustered in the network across 1,722 molecular transmission clusters. TGW who indicated a sexual risk factor clustered at the highest frequency in the network: 147/345 (42.6%) linked to at least one other person (p<0.001). TGW were assortative in the network (0.06; p<0.001), indicating that they tended to link to other TGW. TGW were more likely than expected to link to other TGW and cisgender men who did not identify as men who have sex with men (MSM). TGW were less likely than expected to link to MSM, despite the high prevalence of HIV among MSM. TGW were distributed across 126 clusters, and cis-individuals linked to one TGW were 9.2 times more likely to link to a second TGW than other individuals in the surveillance database. Reconstruction of the transmission network is limited by sample availability, but sequences were available for >40% of diagnoses. Interpretation TGW in LAC were more likely to cluster than any other risk group, suggesting high transmission rates—despite the small number of TGW in the network. TGW tended to cluster with other TGW, indicating shared risk activities (i.e., linked directly or through shared partners). This assortativity, and the observed tendency for linkage with cisgender men who did not identify as MSM, demonstrates the potential to use molecular epidemiology to both identify clusters likely to include undiagnosed HIV-infected TGW and improve the targeting of public health prevention and treatment services to TGW.

Poor engagement in HIV care has been associated with delayed access to antiretroviral treatment and increased HIV transmission. Using viral load (VL) results from HIV laboratory surveillance data to conduct longitudinal and cross-sectional analyses, we examined linkage to care, retention in care, and their associated factors in 37,325 persons living with HIV (PLWH) in Los Angeles County (LAC). Linkage to care was considered timely if a VL test result was present ≤3 months of diagnosis. Successful retention in care was defined as having two or more VL test results ≥90 days apart during 2009. Of 6841 persons newly diagnosed with HIV in 2007-2009, 67% were linked to care within 3 months of diagnosis. Factors associated with delayed linkage to care included being African American, Latino, and Asian/Pacific Islander (adjusted hazard ratio [AHR]=0.81; 95% CI=0.75-0.87, AHR=0.83; 95% CI=0.77-0.89, AHR=0.82; 95% CI=0.71-0.94, respectively). Of the 37,325 PLWH, 52% were retained in care during 2009. Factors associated with lack of retention in care included injection drug use (adjusted prevalence ratio [APR]=0.88; 95% CI=0.84-0.93), incarceration at diagnosis (APR=0.56; 95% CI=0.51-0.61), being diagnosed in pre-highly active antiretroviral therapy (HAART) era (APR=0.94; 95% CI=0.92-0.96) or at a public facility (APR=0.97; 95% CI=0.95-1.00), age <45 years (APR=0.87; 95% CI=0.86-0.89), and having concurrent HIV/AIDS diagnoses (APR=0.94; 95% CI=0.92-0.96). This study demonstrates the value of using VL surveillance data to monitor engagement in care among PLWH, and its potential to improve linkage and retention efforts where disparities in care are observed.

The prevalence of human immunodeficiency virus (HIV) types 1 and 2 infections in Nigeria was estimated from 3854 serum samples collected at 21 locations from 1985 to 1990. Seventy-eight samples (2.0%) were reactive for HIV-1 and 49 (1.3%) for HIV-2 antibodies; 5 samples were reactive for both viruses. The prevalence of HIV-1 and -2 infections, respectively, was highest among 60 female prostitutes, with 10% and 6.7% positive. For other groups the respective rates of positivity were 4.1% and 3.4% in 610 patients with sexually transmitted diseases, 3.6% and 1.4% in 140 tuberculosis patients, 1.6% and 0.6% of 1253 other medical patients, and 1.2% and 0.9% of 1640 volunteer blood donors. Of 153 health care workers, 1.3% were positive for HIV-1 only. The age group from 20 to 29 years had the highest prevalences of HIV-1 (3.3%) and -2 (2.2%). In Nigeria, antibody prevalence for both viruses appears to have increased > 10-fold between 1986 and 1990.

No abstract

The high prevalence of antibodies to subtypes of the two entirely distinct retrovirus groups in young women has important implications for defining epidemiological patterns of diseases associated with co-infections with two or more retroviruses.