Interplay Between Geography and HIV Transmission Clusters in Los Angeles County.

Background: Clusters of HIV diagnoses in time and space and clusters of genetically linked cases can both serve as alerts for directing prevention and treatment activities. We assessed the interplay between geography and transmission across the Los Angeles County (LAC) HIV genetic transmission network.

Methods: Deidentified surveillance data reported for 8186 people with HIV residing in LAC from 2010 through 2016 were used to construct a transmission network using HIV-TRACE.

Sorting by Race/Ethnicity Across HIV Genetic Transmission Networks in Three Major Metropolitan Areas in the United States.

An important component underlying the disparity in HIV risk between race/ethnic groups is the preferential transmission between individuals in the same group. We sought to quantify transmission between different race/ethnicity groups and measure racial assortativity in HIV transmission networks in major metropolitan areas in the United States. We reconstructed HIV molecular transmission networks from viral sequences collected as part of HIV surveillance in New York City, Los Angeles County, and Cook County, Illinois.

The Relationship Between the Human Immunodeficiency Virus-1 Transmission Network and the HIV Care Continuum in Los Angeles County.

Background: Public health action combating human immunodeficiency virus (HIV) includes facilitating navigation through the HIV continuum of care: timely diagnosis followed by linkage to care and initiation of antiretroviral therapy to suppress viral replication. Molecular epidemiology can identify rapidly growing HIV genetic transmission clusters. How progression through the care continuum relates to transmission clusters has not been previously characterized.

HIV transmission networks among transgender women in Los Angeles County, CA, USA: a phylogenetic analysis of surveillance data.

Background: Transgender women are among the groups at highest risk for HIV infection, with a prevalence of 27·7% in the USA; and despite this known high risk, undiagnosed infection is common in this population. We set out to identify transgender women and their partners in a molecular transmission network to prioritise public health activities.

Methods: Since 2006, HIV protease and reverse transcriptase gene (pol) sequences from drug resistance testing have been reported to the Los Angeles County 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.

Using a Multitest Algorithm to Improve the Positive Predictive Value of Rapid HIV Testing and Linkage to HIV Care in Nonclinical HIV Test Sites.

Background: Use of a rapid HIV testing algorithm (RTA) in which all tests are conducted within one client appointment could eliminate off-site confirmatory testing and reduce the number of persons not receiving confirmed results.

Methods: An RTA was implemented in 9 sites in Los Angeles and San Francisco; results of testing at these sites were compared with 23 sites conducting rapid HIV testing with off-site confirmation. RTA clients with reactive results on more than 1 rapid test were considered HIV+ and immediately referred for HIV care.

HIV Infection and Linkage to HIV-Related Medical Care in Large Urban Areas in the United States, 2009.

Background: Residents of urban areas have accounted for the majority of persons diagnosed with HIV disease in the United States. Linking persons recently diagnosed with HIV to primary medical care is an important indicator in the National HIV/AIDS Strategy.

Methods: We analyzed data reported to the HIV Surveillance System in 18 urban areas in the United States.

Prevalence and circulation patterns of variant, atypical and resistant HIV in Los Angeles County (2007-2009).

The prevalence of transmitted HIV drug resistance (TDR) in Los Angeles County remains unknown, due in part to the absence of reliable genotypic data. The specific objectives of this study are to estimate the prevalence of TDR, to describe the demographic characteristics associated with TDR and to investigate the distribution of HIV-1 subtypes among persons newly diagnosed with HIV in Los Angeles County. From 2007 through 2009, 1,414 sequences were obtained from 7,100 persons newly diagnosed with HIV through HIV resistance surveillance.

Late HIV detection among adult males in Los Angeles County, 2000-2004.

We analyzed HIV surveillance data on white, black, and Latino males diagnosed with HIV between 2000 and 2004 in Los Angeles County (LAC) to identify associations between individual- and community-level factors and late HIV detection by race/ethnicity. We defined late HIV detection as an AIDS diagnosis within 6 months of HIV diagnosis. We conducted multilevel analysis to determine individual- and community-level risk factors associated with late HIV detection stratified by race/ethnicity.

Using laboratory surveillance data to estimate engagement in care among persons living with HIV in Los Angeles County, 2009.

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.

Epidemiology of HIV infection in large urban areas in the United States.

Background: While the U.S. HIV epidemic continues to be primarily concentrated in urban area, local epidemiologic profiles may differ and require different approaches in prevention and treatment efforts.

The role of person-to-person transmission in an epidemiologic study of Pneumocystis carinii pneumonia.

Objective: Recent laboratory studies suggest that may be transmitted from person-to-person. Recent exposure to persons with pneumonia (PCP) among HIV-infected persons with and without PCP was assessed to evaluate the person-to-person transmission hypothesis.

Design: A case-control study design was used.