Search

Coronavirus disease-19 (COVID-19) has resulted in much acute morbidity and mortality worldwide. There is now a growing recognition of the post-acute sequela of COVID-19, termed long COVID. However, the risk factors contributing to this condition remain unclear. Here, we address the growing controversy in the literature of whether hospitalization is a risk factor for long COVID. We found that hospitalization is associated with worse pulmonary restriction and reduction in diffusion capacity at 3 months post-infection. However, the impact on mental health, functional and quality of life is equally severe in those who have and have not been hospitalized during the acute infection. These findings suggest that hospitalization is a risk factor for pulmonary complications of long COVID but not the overall severity of long COVID.

Darunavir 800 mg once daily (QD) is indicated for HIV-1-infected treatment-naïve and treatment-experienced (without darunavir resistance-associated mutations [RAMs]) individuals, and has been evaluated in phase 2/3 studies with durations between 48 and 192 weeks.To summarize the development (or identification) of post-baseline resistance (RAMs and antiretroviral phenotypic susceptibility) among patients receiving darunavir QD dosing.Seven phase 2/3 studies with available genotypes/phenotypes for subjects treated with ritonavir- or cobicistat-boosted darunavir 800 mg QD regimens were assessed: ARTEMIS (NCT00258557; n = 343), GS-US-299-0102 (NCT01565850; n = 153), GS-US-216-0130 (NCT01440569; n = 313), ODIN (NCT00524368; n = 294), INROADS (NCT01199939; n = 54), MONET (NCT00458302; n = 256), and PROTEA (NCT01448707; n = 273). Genotypic analyses were conducted at baseline (except switch studies enrolling virologically suppressed subjects [MONET, PROTEA]). Criteria for post-baseline resistance testing and evaluation of the development (or identification [switch studies]) of RAMs (respective IAS-USA mutations) varied slightly across studies.Among 1686 subjects treated with darunavir 800 mg QD regimens, 184 had protocol-defined virologic failure; 182 had post-baseline genotypes analyzed. Overall, 4/1686 (0.2%) developed (or had identified [switch studies]) primary protease inhibitor and/or darunavir RAMs (ARTEMIS, n = 1; GS-US-216-0130, n = 1; ODIN, n = 1; MONET, n = 1). Only 1/1686 (0.1%) subject lost darunavir phenotypic susceptibility (ODIN; possibly related to prior ritonavir-boosted lopinavir virologic failure). Among 1103 subjects using a nucleos(t)ide reverse transcriptase inhibitor (N[t]RTI) backbone, 10 (0.9%) developed ≥ 1 N(t)RTI RAM (8 had the emtricitabine RAM M184I/V).Darunavir has a high genetic barrier to resistance. Across a diverse population of HIV-1-infected subjects treated with darunavir 800 mg QD regimens, the development of darunavir resistance was rare (0.1%).

The efficacy and high barrier to resistance of darunavir have been demonstrated across diverse populations with HIV-1 infection. To evaluate post-baseline resistance among patients in studies of once-daily (QD) darunavir-based regimens and formulations. The analysis included treatment-naïve and virologically failing or suppressed patients from 10 phase 2/3 studies (48–192 weeks in duration) of boosted darunavir 800 mg QD-based regimens. Three were phase 3 studies of the QD darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg single-tablet regimen. Post-baseline resistance was evaluated upon protocol-defined virologic failure (PDVF). Resistance-associated mutations (RAMs) were identified using International Antiviral Society-USA mutation lists. Phenotypic analyses varied across studies. Overall, 250 of 3635 patients in the analysis met PDVF criteria; 205 had post-baseline genotypes/phenotypes. In total, four (0.1%) patients developed (or had identified) ≥1 darunavir and/or primary protease inhibitor (PI) RAM; only one (n = 1949), none had post-baseline darunavir, primary PI, or tenofovir RAMs; only two (0.1%) patients developed an emtricitabine RAM, M184V/I. Across a large, diverse population using darunavir 800 mg QD-based regimens and formulations, resistance development remains rare. After clinical trials that span >10 years, loss of phenotypic susceptibility to darunavir was only observed once in a PI-experienced patient and has never been observed in treatment-naïve patients, treatment-experienced PI-naïve patients, or treatment-experienced virologically suppressed patients.

Background DRV has demonstrated high efficacy and barrier to resistance development across diverse populations, from TN to heavily TE patients. We evaluated resistance data from 10 clinical studies of different DRV 800 mg QD–based antiretroviral regimens and formulations. Methods The analysis included patients from 10 phase 2/3 studies (48–192 weeks in duration) of ritonavir- and cobicistat-boosted DRV 800 mg QD–based regimens in TN and virologically failing or suppressed TE patients with HIV-1 (table). Three were phase 3 studies of the DRV/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg single-tablet regimen (STR). Post-baseline resistance was evaluated in patients experiencing protocol-defined virologic failure (PDVF); definitions and criteria for resistance testing varied slightly among studies. Resistance-associated mutations (RAMs) were based on respective International Antiviral Society–USA mutation lists over time. Results Of the 3,635 patients evaluated, 250 met PDVF criteria and 205 had post-baseline genotypes/phenotypes. Overall, 4 (0.1%) patients developed (or had identified [switch studies]) ≥1 DRV and/or primary protease inhibitor (PI) RAM (table), and only 1 (< 0.1%, ODIN) patient lost DRV phenotypic susceptibility; this TE patient had prior VF with lopinavir. Among those who used a nucleos(t)ide reverse transcriptase inhibitor (NRTI) backbone (mostly emtricitabine [FTC] + tenofovir [TFV]), 12 (0.4%) patients had ≥1 NRTI RAM, including 10 with M184I/V associated with FTC resistance. No TFV RAMs were observed. Among patients receiving D/C/F/TAF (n = 1,949), none had post-baseline DRV, primary PI, or TFV RAMs; only 2 (0.1%) patients developed an FTC RAM. Conclusion Across a large, diverse population using DRV 800 mg QD–based regimens and formulations, resistance development remains rare; 0.1% of patients had ≥1 DRV and/or primary PI RAM post-baseline. Among 3 trials of the D/C/F/TAF STR, no patients developed a DRV or primary PI RAM. After > 10 years of investigating DRV 800 mg QD–based regimens in clinical trials, loss of phenotypic susceptibility to DRV has never been observed in TN or TE virologically suppressed patients and was only once observed in a TE patient with prior VF on multiple antiretrovirals, including a PI. Disclosures All authors: No reported disclosures.

Background Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg is a once-daily, single-tablet regimen approved in Europe and under regulatory review in the United States for the treatment of HIV-1 infection. In the pivotal AMBER trial in antiretroviral treatment (ART)-naïve, HIV-1–infected adults, D/C/F/TAF achieved a high virologic response rate at Week 48 that was noninferior to control (D/C+F/tenofovir disoproxil fumarate); favorable renal/bone outcomes were seen with D/C/F/TAF vs. control. These results were consistent across age, gender, and race subgroups. Here we report Week 48 results in subgroups based on viral load (VL), CD4+ count, and WHO clinical staging of HIV/AIDS at baseline. Methods The phase 3, randomized (1:1), blinded, noninferiority AMBER trial enrolled ART-naïve, HIV-1–infected adults. The primary endpoint was the proportion of patients with virologic response (VL 100,000 copies/mL), CD4+ count (< vs. ≥350 cells/µL), and WHO clinical stage (1 vs. 2 vs. 3 vs. 4) at baseline. Results Of the 725 patients randomized and treated, the majority had VL ≤100,000 copies/mL (82% of patients), CD4+ count ≥350 cells/µL (72%), and WHO clinical stage 1 (84%) at baseline. Overall virologic response rates were 91.4% with D/C/F/TAF and 88.4% with control; results were similar across baseline VL, CD4+ count, and WHO clinical stage subgroups (figure). Overall rates of serious AEs, grade 3–4 AEs, and AE-related discontinuations were similar for D/C/F/TAF (n = 17 [4.7%], n = 19 [5.2%], and n = 7 [1.9%], respectively) and control (n = 21 [5.8%], n = 22 [6.1%], and n = 16 [4.4%]), as well as across subgroups (table). Conclusion D/C/F/TAF achieved high (91.4%), noninferior virologic response rates vs. control (88.4%) in ART-naïve, HIV-1–infected adults. Consistent and robust efficacy and safety results were found with D/C/F/TAF vs. control based on VL, CD4+ count, and WHO clinical stage at baseline. Disclosures B. Rashbaum, Gilead: Shareholder and Speaker’s Bureau: Any financial benefit related to being a shareholder and Speaker honorarium. C. Mcdonald, Gilead: Various, Personal fees. Merck: Various, Personal fees. ViiV: Various, Personal fees. Janssen: Various, Personal fees. D. Luo, Janssen: Employee, Salary. J. Jezorwski, Janssen: Employee, Salary. K. Brown, Janssen: Employee, Salary. E. Y. Wong, Janssen: Employee, Salary.

Non-medical, community-based workers play a critical role in supporting people living with (or at risk of acquiring) HIV along the care continuum. The biomedical nature of promising advances in HIV prevention, such as pre-exposure prophylaxis and treatment-as-prevention, requires frontline workers to be knowledgeable about HIV science and treatment. This study was developed to: measure knowledge of HIV science and treatment within the HIV non-medical workforce, evaluate workers' familiarity with and attitudes toward recent biomedical interventions, and identify factors that may affect HIV knowledge and attitudes. A 62-question, web-based survey was completed in English or Spanish between 2012 and 2014 by 3663 US-based employees, contractors, and volunteers working in AIDS service organizations, state/local health departments, and other community-based organizations in a non-medical capacity. Survey items captured the following: respondent demographics, HIV science and treatment knowledge, and familiarity with and attitudes toward biomedical interventions. An average of 61% of HIV knowledge questions were answered correctly. Higher knowledge scores were associated with higher education levels, work at organizations that serve people living with HIV/AIDS or who are at a high risk of acquiring HIV, and longer tenure in the field. Lower knowledge scores were associated with non-Hispanic Black or Black race/ethnicity and taking the survey in Spanish. Similarly, subgroup analyses showed that respondents who were non-Hispanic Black or Hispanic (versus non-Hispanic white), as well as those located in the South (versus other regions) scored significantly lower. These subpopulations were also less familiar with and had less positive attitudes toward newer biomedical prevention interventions. Respondents who took the survey in Spanish (versus English) had lower knowledge scores and higher familiarity with, but generally less positive attitudes toward, biomedical interventions. In summary, low knowledge scores suggest the need for additional capacity-building efforts and training for non-medical HIV workers, particularly those who provide services in the communities most affected by HIV.

Accurate HIV diagnostic testing continues to pose challenges, but there are also opportunities for assay performance improvements in key areas for specific intended-use settings. The genetic diversity of HIV can result in false and discordant results in assays that fail to detect new variant strains. The use of antiretroviral therapies has resulted in drug-resistant variants that require monitoring by sequencing and genotyping methods. Nucleic acid testing is the most sensitive and reliable platform for detection, but it is costly and limited to centralized testing facilities, making implementation difficult in resource-limited settings where HIV has hit the hardest. Rapid antibody tests suitable for point-of-care use are becoming more accessible in resource-limited settings, but these tests may not detect HIV during the acute infection stage. Emerging antigen/antibody combination assays are viable alternatives to nucleic acid testing for diagnosis of recent infections. Although patient monitoring (e.g., via CD4+T-cell count and viral load determination) and infant diagnoses still rely on clinical laboratory-based testing, point-of-care options are being developed. There are other technical challenges to HIV diagnostic testing and emerging biodetection technologies that may be able to address them, but they are not yet proven.

Mammalian sterile 20 (MST1) kinase, a member of the sterile 20 (Ste-20) family of proteins, is a proapoptotic cytosolic kinase that plays an important role in the cellular response to oxidative stress. In this study, we report on the development of a potent and selective MST1 kinase inhibitor based on a ruthenium half-sandwich scaffold. We show that the enantiopure organoruthenium inhibitor, 9E1, has an IC50 value of 45 nM for MST1 and a greater than 25-fold inhibitor selectivity over the related Ste-20 kinases, p21 activated kinase 1 (PAK1), and p21 activated kinase 4 (PAK4) and an almost 10-fold selectivity over the related thousand-and-one amino acids kinase 2 (TAO2). Compound 9E1 also displays a promising selectivity profile against unrelated protein kinases; however, the proto-oncogene serine/threonine protein kinase PIM1 (PIM-1) and glycogen synthase kinase 3 (GSK-3beta) are inhibited with IC50 values in the low nanomolar range. We also show that 9E1 can inhibit MST1 function in cells. A cocrystal structure of a related compound with PIM-1 and a homology model with MST1 reveals the binding mode of this scaffold to MST1 and provides a starting point for the development of improved MST1 kinase inhibitors for possible therapeutic application.

Miniaturizing bioassays to the nanoliter scale for high-throughput screening reduces the consumption of reagents that are expensive or difficult to handle. Through the use of acoustic dispensing technology, nanodroplets containing 10 microM ATP (3 microCi/microL (32)P) and reaction buffer in 10% glycerol were positionally dispensed to the surface of glass slides to form 40-nL compartments (100 droplets/slide) for Pim1 (proviral integration site 1) kinase reactions. The reactions were activated by dispensing 4 nL of various levels of a pyridocarbazolo-cyclopentadienyl ruthenium complex Pim1 inhibitor, followed by dispensing 4 nL of a Pim1 kinase and peptide substrate solution to achieve final concentrations of 150 nM enzyme and 10 microM substrate. The microarray was incubated at 30 degrees C (97% R(h)) for 1.5 h. The spots were then blotted to phosphocellulose membranes to capture phosphorylated substrate. With phosphor imaging to quantify the washed membranes, the assay showed that, for doses of inhibitor from 0.75 to 3 microM, Pim1 was increasingly inhibited. Signal-to-background ratios were as high as 165, and average coefficients of variation for the assay were approximately 20%. Coefficients of variation for dispensing typical working buffers were under 5%. Thus, microarrays assembled by acoustic dispensing are promising as cost-effective tools that can be used in protein assay development.

Doping is a process in which atomic impurities are intentionally added to a host material to modify its properties. It has had a revolutionary impact in altering or introducing electronic, magnetic, luminescent, and catalytic properties for several applications, for example in semiconductors. Here we explore and demonstrate the extension of the concept of substitutional atomic doping to nanometre-scale crystal doping, in which one nanocrystal is used to replace another to form doped self-assembled superlattices. Towards this goal, we show that gold nanocrystals act as substitutional dopants in superlattices of cadmium selenide or lead selenide nanocrystals when the size of the gold nanocrystal is very close to that of the host. The gold nanocrystals occupy random positions in the superlattice and their density is readily and widely controllable, analogous to the case of atomic doping, but here through nanocrystal self-assembly. We also show that the electronic properties of the superlattices are highly tunable and strongly affected by the presence and density of the gold nanocrystal dopants. The conductivity of lead selenide films, for example, can be manipulated over at least six orders of magnitude by the addition of gold nanocrystals and is explained by a percolation model. As this process relies on the self-assembly of uniform nanocrystals, it can be generally applied to assemble a wide variety of nanocrystal-doped structures for electronic, optical, magnetic, and catalytic materials.

A model has been developed to examine, on a local scale, the reactions of rocket exhaust from solid rocket motors with stratospheric ozone. The effects were examined at two different altitudes. Results of the modeling study indicate that afterburning chemistry of reactive exhaust products can cause local but transient (on the order of several minutes) loss of ozone. The modeling study included potential heterogeneous reactions at aluminum oxide surfaces. Results indicate that these potential heterogeneous reactions do not have a major impact on the local plume chemistry. Homogeneous reactions appear to be of more consequence during the early dispersion of the plume. It has also been found that the rate of plume dispersion has a very significant effect on local ozone loss.

Background For more than a decade there has been increasing interest in the use of nanotechnology and microarray platforms for diagnostic applications. In this report, we describe a rapid and simple gold nanoparticle (NP)-based genomic microarray assay for specific identification of avian influenza virus H5N1 and its discrimination from other major influenza A virus strains (H1N1, H3N2). Results Capture and intermediate oligonucleotides were designed based on the consensus sequences of the matrix (M) gene of H1N1, H3N2 and H5N1 viruses, and sequences specific for the hemaglutinin (HA) and neuraminidase (NA) genes of the H5N1 virus. Viral RNA was detected within 2.5 hours using capture-target-intermediate oligonucleotide hybridization and gold NP-mediated silver staining in the absence of RNA fragmentation, target amplification, and enzymatic reactions. The lower limit of detection (LOD) of the assay was less than 100 fM for purified PCR fragments and 103 TCID50 units for H5N1 viral RNA. Conclusions The NP-based microarray assay was able to detect and distinguish H5N1 sequences from those of major influenza A viruses (H1N1, H3N2). The new method described here may be useful for simultaneous detection and subtyping of major influenza A viruses.

The HIV-1 capsid protein, p24 antigen, is of considerable diagnostic interest because following HIV exposure it is detectable several days earlier than host-generated HIV antibodies (which are the target of almost all current tests used in the field) and can be used to design very sensitive assays without the need for PCR. Here, we present an ultrasensitive capacitive immunosensor that is capable of detecting subattogram per milliliter concentrations of p24 antigen, which to our knowledge is the lowest level of detection ever reported. Dilution studies using p24-spiked human plasma samples indicate that the immunosensor is robust against the interfering effects of a complex biological matrix. Moreover, the capacitive immunosensor assay is rapid (

To further refine our current nanoparticle-based HIV-1 p24 antigen assay, we investigated immune responses to p24 to identify diagnostically significant immune dominant epitopes (IDEs) in HIV-infected human sera, to address cross-reactivity of anti-p24 antibodies to different subtypes, and to identify new biomarkers that distinguish acute from chronic HIV infection for more accurate incidence estimation. We identified two major linear epitope regions, located in the CypA binding loop and adjacent helices and at the end of the C-terminal domain. Most sera (86%) from acutely HIV-1-infected individuals reacted with multiple peptides, while 60% and 30% of AIDS patient samples reacted with multiple and single peptides, respectively. In contrast, 46% and 43% of chronically HIV-1-infected individuals reacted with one and none of the peptides, respectively, and only 11% reacted with multiple p24 peptides, indicating a progression of immune responses from polyclone-like during acute infection to monoclone-like or a nonresponse to linear epitopes during chronic infection. Anti-p24 antibodies (subtype B) show broad cross-reactivity to different HIV-1 subtypes, and the synergistic action of different combinations of anti-HIV antibodies improves capture and detection of divergent HIV-1 subtypes. Our results indicate that the modified peptide immunoassay is sensitive and specific for the rapid identification of HIV-1 p24 IDEs and for investigation of immune responses to p24 during natural HIV-1 infection. The data provide the foundation for development and refinement of new assays for improved p24 antigen testing as future tools for rapid and accurate diagnosis as part of early intervention strategies and estimations of incidence.

Organometallic pyridocarbazole scaffolds are investigated as protein kinase inhibitors. Whereas our previous designs employed solely a maleimide pharmacophore for achieving the two crucial canonical hydrogen bonds to the hinge region of the ATP binding site, we have now extended our investigations to include the related lactam metallo-pyridocarbazoles. The synthetic access of the two regioisomeric lactam pyridocarbazoles is described, and the distinct biological properties of the two lactam scaffolds are revealed by employing a ruthenium half sandwich complex as a model system, resulting in organometallic lead structures for the inhibition of the protein kinases TrkA and CLK2. These new lactam metallo-pyridocarbazoles expand our existing molecular toolbox and assist toward the generation of metal complex scaffolds as lead structures for the design of selective inhibitors for numerous kinases of the human kinome.

Helium-hyperoxia (HH) reduces dyspnea and increases exercise tolerance in patients with COPD. We investigated whether breathing HH would allow patients to perform a greater intensity of exercise and improve the benefits of a pulmonary rehabilitation program.Thirty-eight nonhypoxemic patients with COPD (FEV(1)=47 +/- 17%(pred)) were randomized to rehabilitation breathing HH (60:40 He:O(2); n = 19) or air (n = 19). Patients cycled for 30 min, 3 days/week for 6 weeks breathing the assigned gas. Exercise intensity was prescribed from baseline, gas-specific, incremental exercise tests and was advanced as tolerated. The primary outcome was exercise tolerance assessed as a change in constant-load exercise time (CLT) following rehabilitation. Secondary outcomes were changes in exertional symptoms, health related quality of life (as assessed by the Short-form 36 and St George respiratory questionnaires), and peak oxygen consumption during an incremental exercise test.The HH group had a greater change in CLT following rehabilitation compared to the air group (9.5 +/- 9.1 vs 4.3 +/- 6.3 min, p0.05). At an exercise isotime, dyspnea was significantly reduced in both groups, while leg discomfort only decreased in the HH group. The changes in exertional symptoms and peak oxygen consumption were not different between groups. Health-related quality of life significantly improved in both groups; however, the change in St. George respiratory questionnaire total score was greater with HH (-7.6 +/- 6.4 vs -3.6 +/- 5.6, p0.05). During rehabilitation, the HH group achieved a higher exercise intensity and training duration throughout the program (p0.05).Breathing HH during pulmonary rehabilitation increases the intensity and duration of exercise training that can be performed and results in greater improvements in CLT for patients with COPD.

There is continuing concern about the depletion of the ozone layer. Recently it has been determined that effluents from rockets exhausts contain chemical species that can be classified as Potentially Ozone Reactive Chemicals (PORCs). Calculations on the destruction of ozone layer suggest that rockets contribute about 1% to the overall depletion on a yearly basis. This has motivated studies to determine methods and processes which can reduce the amount of ozone depletion. This study examines the use of alternate propellants to reduce the production of PORCs. The methodology is straightforward. The composition of a current solid rocket is examined and those chemical species which are classified as PORCs are identified. Alternate propellants are identified which reduce or eliminate the production of those PORCs. Not surprisingly, some of the exhaust species produced by the alternate propellants are classified as PORCs. The amounts of the species are quantified and found to be acceptably small. The technology status of these propellants and the rocket engines that would utilize them is briefly summarized. The safety, handling and toxicity characteristics of alternate propellants are presented.

The Environmental Management of the Space and Missile Systems Command has set out to evaluate the depletion of stratospheric ozone caused by Air Force activities in space. Potential destruction of ozone by launch vehicle exhaust is one item of concern (Ref. 1.1). The use of advanced propellants to minimize launch-induced ozone destruction is discussed in a companion report. The present report describes a quantitative assessment of another potential destroyer of stratospheric ozone: deorbiting space debris. The results of the present study lead to the conclusion that deorbiting space debris has very little impact on stratospheric ozone.

Grad's thirteen-moment equations are applied to the flow behind a bow shock under the formalism of a thin shock layer. Comparison of this version of the theory with Direct Simulation Monte Carlo calculations of flows about a flat plate at finite attack angle has lent support to the approach as a useful extension of the continuum model for studying translational nonequilibrium in the shock layer. This paper reassesses the physical basis and limitations of the development with additional calculations and comparisons. The streamline correlation principle, which allows transformation of the 13-moment based system to one based on the Navier-Stokes equations, is extended to a three-dimensional formulation. The development yields a strip theory for planar lifting surfaces at finite incidences. Examples reveal that the lift-to-drag ratio is little influenced by planform geometry and varies with altitudes according to a 'bridging function' determined by correlated two-dimensional calculations.

The concept of a viscous shock-layer and several related versions of continuum theories/methods are examined for their adequacy as a viable framework to study flow physics and aerothermodynamics of relevance to sustained hypersonic flights. Considering the flat plate at angle of attack, or the wedge, as a generic example for the major aerodynamic component of a hypersonic vehicle, the relative importance of the molecular-transport effects behind the shock (in the form of the 'shock slip') and the wall-slip effects are studied. In the flow regime where the shock-transition-zone thickness remains small compared to the shock radius of curvature, a quasi-one-dimensional shock structure under the Burnett/thirteen-moment approximation, as well as particulate/collisional models, can be consistently developed. The fully viscous version of the shock-layer model is shown to provide the crucial boundary condition downstream the shock in this case. The gas-kinetic basis of the continuum description for the flow behind the bow shock, and certain features affecting the non-equilibrium flow chemistry, are also discussed.

Background The Centers for Disease Control and Prevention recommends routine HIV testing in all healthcare settings, but it is unclear how consistently physicians adopt the recommendation. Making the most of each interaction between black physicians and their patients is extremely important to address the HIV health disparities that disproportionately afflict the black community. The goal of this survey-based study was to evaluate the perceptions and practices of black, primary care physicians regarding HIV testing. Methods A physician survey was administered at the 2010 National Medical Association Annual Convention, via online physician panels, and by email. Physician eligibility criteria: black race; practicing at least 1 year in the US; practice comprised of at least 60% adults and 20% black patients. Contingency tables and ordinary least squares regression were used for comparisons and statistical analyses. A Chi-square test compared percentages of physicians who gave a particular response and a t-test compared the means of values provided by physicians. Results Physicians over-estimated HIV prevalence and believed that HIV is a crisis in the black community, yet reported that only 34% of patients were HIV tested in the past year. Physicians reported that 67% of those patients tested did so due to a physician recommendation. Physicians who were younger, female, obstetricians/gynecologists, and had a higher proportion of black, low-socioeconomic status, and Medicaid patients reported higher testing rates. Most testing was risk-based rather than routine, and three of the five most commonly reported barriers to testing were related to disease stigma and perceived value judgments. Physicians reported that in-office patient informational materials, increased media attention, additional education and training on HIV testing, government mandates requiring routine testing, and accurate pre-packed tests would most help them test more frequently for HIV. Conclusions In this sample of black, primary care physicians, HIV testing practices differed according to physician characteristics and practice demographics, and overall reported testing rates were low. More physician education and training around testing guidelines is needed to enable more routine testing, treatment, and long-term management of patients with HIV.