Antiretroviral therapy in adults: updated recommendations of the International AIDS Society-USA Panel

OBJECTIVE

To update recommendations for antiretroviral therapy for adult human immunodeficiency virus type 1 (HIV-1) infection, based on new information and drugs that are available.

PARTICIPANTS

A 17-member international physician panel with antiretroviral research and HIV patient care experience initially convened by the International AIDS Society-USA in December 1995.

EVIDENCE

Available clinical and basic science data including phase 3 controlled trials; data on clinical, virologic, and immunologic end points; research conference reports; HIV pathogenesis data; and panel expert opinion. Recommendations were limited to therapies available (US Food and Drug Administration approved) in 1999.

CONSENSUS PROCESS

The panel assesses new research reports and interim results and regularly meets to consider how the new data affect therapy recommendations. Recommendations are updated via full-panel consensus. Guidelines are presented as recommendations if the supporting evidence warrants routine use in the particular situation and as considerations if data are preliminary or incomplete but suggestive.

CONCLUSIONS

The availability of new antiretroviral drugs has expanded treatment choices. The importance of adherence, emerging long-term complications of therapy, recognition and management of antiretroviral failure, and new monitoring tools are addressed. Optimal care requires individualized management and ongoing attention to relevant scientific and clinical information in the field.

Rifampin and pyrazinamide vs isoniazid for prevention of tuberculosis in HIV-infected persons: an international randomized trial. Terry Beirn Community Programs for Clinical Research on AIDS, the Adult AIDS Clinical Trials Group, the Pan American Health Organization, and the Centers for Disease Control and Prevention Study Group

CONTEXT

Because of problems with adherence, toxicity, and increasing resistance associated with 6- to 12-month isoniazid regimens, an alternative short-course tuberculosis preventive regimen is needed.

OBJECTIVE

To compare a 2-month regimen of daily rifampin and pyrazinamide with a 12-month regimen of daily isoniazid in preventing tuberculosis in persons with human immunodeficiency virus (HIV) infection.

DESIGN

Randomized, open-label controlled trial conducted from September 1991 to May 1996, with follow-up through October 1997.

SETTING

Outpatient clinics in the United States, Mexico, Haiti, and Brazil.

PARTICIPANTS

A total of 1583 HIV-positive persons aged 13 years or older with a positive tuberculin skin test result.

INTERVENTIONS

Patients were randomized to isoniazid, 300 mg/d, with pyridoxine hydrochloride for 12 months (n = 792) or rifampin, 600 mg/d, and pyrazinamide, 20 mg/kg per day, for 2 months (n = 791).

MAIN OUTCOME MEASURES

The primary end point was culture-confirmed tuberculosis; secondary end points were proven or probable tuberculosis, adverse events, and death, compared by treatment group.

RESULTS

Of patients assigned to rifampin and pyrazinamide, 80% completed the regimen compared with 69% assigned to isoniazid (P<.001). After a mean follow-up of 37 months, 19 patients (2.4%) assigned to rifampin and pyrazinamide and 26 (3.3%) assigned to isoniazid developed confirmed tuberculosis at rates of 0.8 and 1.1 per 100 person-years, respectively (risk ratio, 0.72 [95% confidence interval, 0.40-1.31]; P = .28). In multivariate analysis, there were no significant differences in rates for confirmed or probable tuberculosis (P = .83), HIV progression and/or death (P = .09), or overall adverse events (P = .27), although drug discontinuation was slightly higher in the rifampin and pyrazinamide group (P = .01). Neither regimen appeared to lead to the development of drug-resistant tuberculosis.

CONCLUSIONS

Our data suggest that for preventing tuberculosis in HIV-infected patients, a daily 2-month regimen of rifampin and pyrazinamide is similar in safety and efficacy to a daily 12-month regimen of isoniazid. This shorter regimen offers practical advantages to both patients and tuberculosis control programs.

Clinical interpretation of airway response to a bronchodilator. Epidemiologic considerations

Airways responsiveness to a bronchodilator is frequently measured to assist in determining the cause of respiratory symptoms. Clinically, a greater than 15% improvement in the FEV1 is often used to define the "increased" response indicative of asthma. However, unlike other tests of lung function, reference standards derived from "healthy" members of a general population sample have never been reported. As part of a health survey carried out in Alberta, Canada, 2,609 subjects completed a standardized respiratory symptom questionnaire and had FEV1 measured before and 20 min after inhaling terbutaline sulfate via a 750-ml spacer device. Among asymptomatic never-smoking subjects with a FEV1 greater than 80% of predicted, the upper 95th percentile of bronchodilator response (BDR), when expressed as 100 x (FEV1 postBDR - FEV1 preBDR)/predicted baseline FEV1 averaged 9%. This value remained remarkably stable across gender, age (7 to 75 yr), and height groups, and deviated to 6% only when baseline FEV1 was greater than 120% of predicted. Consistent with other respiratory function variables, in which the upper limit of normal is often defined as the upper 95th percentile, our population-derived reference values provide a conceptual definition of BDR that can easily be applied to define "increased" response in the clinical setting.

Dual and recombinant infections: an integral part of the HIV-1 epidemic in Brazil

We systematically evaluated multiple and recombinant infections in an HIV-infected population selected for vaccine trials. Seventy-nine HIV-1 infected persons in a clinical cohort study in Rio de Janeiro, Brazil, were evaluated for 1 year. A combination of molecular screening assays and DNA sequencing showed 3 dual infections (3.8%), 6 recombinant infections (7.6%), and 70 (88.6%) infections involving single viral subtypes. In the three dual infections, we identified HIV-1 subtypes F and B, F and D, and B and D; in contrast, the single and recombinant infections involved only HIV-1 subtypes B and F. The recombinants had five distinct B/F mosaic patterns: Bgag-p17/Bgag-p24/Fpol/Benv, Fgag-p17/Bgag-p24/Fpol/Fenv, Bgag-p17/B-Fgag-p24/Fpol/Fenv, Bgag-p17/B-Fgag-p24/Fpol/Benv, and Fgag-p17/B-Fgag-p24/Fpol/Fenv. No association was found between dual or recombinant infections and demographic or clinical variables. These findings indicate that dual and recombinant infections are emerging as an integral part of the HIV/AIDS epidemic in Brazil and emphasize the heterogenous character of epidemics emerging in countries where multiple viral subtypes coexist.

Effect of antiretroviral therapy on HIV shedding in semen

BACKGROUND

The effect of antiretroviral therapy on seminal HIV shedding in the community remains unknown.

OBJECTIVE

To evaluate the effect of antiretroviral therapy on HIV shedding in semen.

DESIGN

Prospective cohort study.

SETTING

University hospital in Rio de Janeiro, Brazil.

PATIENTS

93 HIV-infected men.

INTERVENTION

Antiretroviral therapy as prescribed by each patient's physician.

MEASUREMENT

HIV RNA in semen and blood plasma before and after introduction of therapy.

RESULTS

At baseline, HIV RNA was detected in 69 semen samples (74%) and 89 blood samples (96%). Six months after introduction of therapy, HIV RNA was detected in 29 semen samples (33%) and 33 blood samples (38%). The mean reduction in levels of HIV RNA in semen at 6 months was 1.65 log10 units.

CONCLUSIONS

Antiretroviral therapy reduces shedding of HIV in semen, which probably in tum reduces HIV transmissibility. However, a substantial proportion of patients may still be infectious and may have drug-resistant strains of the virus.

Identification of single and dual infections with distinct subtypes of human immunodeficiency virus type 1 by using restriction fragment length polymorphism analysis

The simultaneous presence of multiple HIV-1 subtypes has become common in communities with the growth of the pandemic. As a consequence, the potentiality for an increased frequency of HIV-1 mixed infections caused by viruses of distinct subtypes could be expected. Thus, there is a need to estimate the prevalence and geographic distribution of infections caused by viruses of a singular subtype as well as coinfections caused by two or more HIV-1 strains of distinct subtypes. To address this need, we have developed a genetic method based on restriction fragment length polymorphism (RFLP) to screen for these two types of infections within infected populations. In this assay, restriction enzymes may be used to predict the phylogroup of HIV-1 infected samples. A 297 bp pol fragment spanning the entire viral protease gene and a 311 bp fragment of the p24 gag region are used for this analysis. The viral regions are amplified by nested PCR using DNA templates from uncultured peripheral blood mononuclear cells (PBMC) or virus culture. Classification of HIV-1 strains to well defined subtypes B, D, F, and A/C is done by sequential endonuclease restriction analysis of a PCR amplified-protease gene followed by analysis of the p24 gag region. The electrophoretic migration patterns visualized by ethidium bromide staining or by radiolabeled probes are then determined on a 10% polyacrylamide gel. In infections caused by viruses of a singular subtype, a single restriction pattern is detected, whereas in multiple infections caused by two or more viral strains of different subtypes, the combination of different digestion patterns are observed in infected individuals. Using this methodology we have screened for genetic variations in HIV-1 proviral DNA from thirty-three Brazilian samples. Our RFLP procedure classified thirty-two samples as single infections caused by viruses of subtypes B (31) and F (1), and one sample as dual infection caused by distinct viral strains. Subsequent sequence and phylogenetic analysis of the viral protease gene in lymphocytes of all these patients confirmed our RFLP findings in single infections, and demonstrated the existence of two distinct HIV-1 strains of subtypes F and D in a patient which lymphocytes showed the simultaneous presence of two different digestion patterns. As up to now, single infections caused by subtype D variants were not identified in Brazil, our data provide the first evidence of subtype D HIV-1 in this country. Because sequencing of HIV proviral DNA is not particularly practical for large-scale molecular epidemiological studies, the protease/gag-based RFLP screening method will be useful to predict the phylogroup of HIV-1, and to identify multiple infections caused by HIV-1 strains of distinct subtypes. We believe that this information is crucial for both evaluation of the HIV-1/AIDS pandemic and intervention strategies.

CD4+ blood lymphocytes are rapidly killed in vitro by contact with autologous human immunodeficiency virus-infected cells

We have investigated the ability of human immunodeficiency virus (HIV)-infected cells to kill uninfected CD4+ lymphocytes. Infected peripheral blood mononuclear cells were cocultured with autologous 51Cr-labeled uninfected cells. Rapid death of the normal CD4-expressing target population was observed following a brief incubation. Death of blood CD4+ lymphocytes occurred before syncytium formation could be detected or productive viral infection established in the normal target cells. Cytolysis could not be induced by free virus, was dependent on gp120-CD4 binding, and occurred in resting, as well as activated, lymphocytes. CD8+ cells were not involved in this phenomenon, since HIV-infected CEMT4 cells (CD4+, CD8- cells) mediated the cytolysis of uninfected targets. Reciprocal isotope-labeling experiments demonstrated that infected CEMT4 cells did not die in parallel with their targets. The uninfected target cells manifested DNA fragmentation, followed by the release of the 51Cr label. Thus, in HIV patients, infected lymphocytes may cause the depletion of the much larger population of uninfected CD4+ cells without actually infecting them, by triggering an apoptotic death.

HIV prevention in developed countries

HIV prevention in developed countries is marked by impressive successes and dismal failures. The successes point the way to what works; the failures highlight obstacles that must be overcome. Successes include important behavioural changes among gay and bisexual men, antiviral use to prevent vertical transmission, and securing the safety of the blood supply. New strategies are needed to reach the residual of individuals continuing with unsafe practices (a special hazard in high-prevalence areas); to reach young people who are beginning to engage in sexual relations and injection drug use; and to overcome political opposition to prevention strategies.

Percutaneous cecostomy for Ogilvie syndrome: laboratory observations and clinical experience

Percutaneous cecostomy (PCC) was evaluated in dogs and cadavers and by means of review of intraperitoneal contrast material-enhanced computed tomographic (CT) scans and clinical experience in five patients with Ogilvie syndrome. It was shown that PCC can be accomplished with a variety of techniques (e.g. Seldinger or trocar puncture, tacking) and instruments (various types and sizes of retention and nonretention catheters). Anatomic studies revealed that the cecum is surrounded by the peritoneum for as much as 270 degrees of its circumference, so that a retroperitoneal approach to PCC would probably be unfeasible in most patients. PCC was effective in treating all five patients in this study, despite their advanced age and complicated medical conditions. Decompression of colonic gas was achieved with 8-12-F catheters, and no major complications occurred. Endoscopic decompression had been unsuccessfully attempted in four of the patients previously. It is concluded that PCC may be an important option in the treatment of Ogilvie syndrome and that the procedure may obviate surgery and be lifesaving in certain high-risk patients.

Myelopathy among Brazilians coinfected with human T-cell lymphotropic virus type I and HIV

OBJECTIVE

To determine whether subjects coinfected with HTLV-I and HIV have a higher frequency of myelopathy than subjects singly infected with HIV.

DESIGN

A prospective, nested case-control study of HTLV-I and HIV coinfected (cases) and HIV singly infected adults (controls) participating in a prospective HIV cohort study at a university hospital outpatient HIV clinic in Rio de Janeiro, Brazil.

MEASUREMENTS

Subjects were evaluated for evidence of myelopathy by a neurologist unaware of their HTLV serologic status. Patients with at least two pyramidal signs, such as paresis, hypertonicity or spasticity, hyperreflexia, clonus, diminished or absent superficial reflexes, or the presence of pathologic reflexes (e.g., Babinski or Hoffmann), were defined as having myelopathy. Myelopathy severity was quantified using the Kurtzke Functional Disability Scale (FDS); patients with FDS scores > or = 4 were considered to have significant myelopathy. Selected patients with myelopathy underwent lumbar puncture for the evaluation of intrathecal synthesis of HTLV-I antibodies.

RESULTS

Of 15 coinfected subjects, 11 (73%) had evidence of myelopathy versus 10 of 62 subjects (16%) with HIV single infection (adjusted odds ratio [OR] = 13.0, p = 0.00002). When only myelopathy patients with FDS scores of > or = 2 or > or = 4 were included, the association between coinfection and the presence of myelopathy remained (OR = 7.3, p = 0.0003 for scores > or = 2; and OR = 8.9 for scores > or = 4, p = 0.04). In addition, a higher proportion of coinfected subjects had peripheral neuropathy (40%) than controls (16%) (OR = 3.5, p = 0.07).

CONCLUSION

Coinfection with HTLV-I was strongly associated with myelopathy among subjects infected with HIV. The relative contribution of HTLV-I versus HIV in the pathogenesis of coinfection-associated myelopathy is not known. Coinfection may also be associated with peripheral neuropathy. Further studies are needed to elucidate the mechanisms of coinfection-associated neurologic conditions.

Horizontal and vertical transmission of human immunodeficiency virus type 1 dual infections caused by viruses of subtypes B and C

This article describes a case of horizontal (heterosexual) and subsequent vertical (mother to infant) transmission of 2 human immunodeficiency viruses type 1 (HIV-1) subtypes. Dual infection in a husband, his wife, and their child was initially detected by use of a restriction fragment length polymorphism assay of the proviral protease in peripheral blood mononuclear cells. The simultaneous presence of highly similar sets of HIV-1 subtypes B and C infecting the 3 family members was confirmed by DNA sequence analysis of pol, gag, and env genes. These data, together with available epidemiologic information, may indicate that the husband's high-risk sexual behavior was the source of dual infections. Because his wife did not report such activities, it was likely that he passed HIV-1 strains to his spouse, who subsequently transmitted them to their child.

Human T cell lymphotropic virus type I does not increase human immunodeficiency virus viral load in vivo

Human T lymphotropic virus type I (HTLV-I) can increase human immunodeficiency virus (HIV) replication in vitro, and several studies suggest that HTLV-I accelerates the progression of HIV infection. To determine whether HTLV-I enhances HIV replication in vivo, a case-control study was done of serum HIV viral load, using polymerase chain reaction, in 23 subjects with HTLV-I/HIV coinfection and 92 control subjects with HIV single infection. The geometric mean serum RNA level was 11,482 copies/mL in the coinfected group and 13,804 in the single-infection group (P = .57), a result that did not change after adjustment for zidovudine use and CD4 cell count. Among subjects with advanced HIV infection, there was a trend toward higher viral load among singly infected subjects. HTLV-I did not appear to increase HIV plasma RNA levels in subjects with coinfection. These results do not provide a biologic basis for the hypothesis that HTLV-I accelerates the course of HIV infection.

HIV viral load and CD4+ lymphocyte counts in subjects coinfected with HTLV-I and HIV-1

Reports indicate that there is a dissociation between markers of HIV disease progression and clinical stage among subjects coinfected with human T-cell lymphotropic virus type I (HTLV-I) and HIV. HTLV-I coinfection does not appear to affect HIV viral load, currently considered to be the best marker of HIV disease progression. We measured HIV RNA levels in stored serum samples from 23 subjects with coinfection and 92 subjects with HIV single infection and examined the correlation with the CD4+ lymphocyte count. Subjects were recruited from an ongoing HIV cohort study in Rio de Janeiro, Brazil. In both groups, CD4+ lymphocyte counts declined with increasing levels of HIV RNA. In a linear regression analysis adjusting for HIV RNA serum level, coinfected individuals had an estimated 78% higher CD4+ lymphocyte count than those with single infection. Simultaneous adjustment for beta2-microglobulin level increased the difference, with coinfected individuals having 146% (p = 0.005, 95% CI: 32% to 359%) higher CD4+ counts. These data suggest that the higher CD4+ lymphocyte counts associated with coinfection do not provide immunologic benefit and may reflect HTLV-I-associated nonspecific lymphocyte proliferation. The results of this and other studies suggest that the CD4+ count cutoff values used in making clinical decisions in HIV infection may not be appropriate in coinfection. As with HIV single infection, HIV virus load may be the optimal surrogate marker for subjects with coinfection.

Chemoprophylaxis for tuberculosis and survival of HIV-infected patients in Brazil

OBJECTIVE

To study the impact of chemoprophylaxis for tuberculosis on the survival of HIV-infected patients with a positive tuberculin skin test.

DESIGN

Prospective observational cohort study.

SETTING

Outpatient clinic of a university hospital, in Rio de Janeiro, Brazil.

PATIENTS

Two-hundred and ninety-seven patients with a positive tuberculin skin test (reaction > or = 5mm) who were admitted to the cohort between January 1991 and December 1994. Follow-up ended on September 30, 1998.

INTERVENTION

The use of chemoprophylaxis for tuberculosis.

MAIN OUTCOME MEASURES

Death was the primary outcome variable. The occurrence of tuberculosis was studied as a secondary outcome. Cox regression models were used in these analyses.

RESULTS

The median follow-up time was 43.6 months. Chemoprophylaxis was used by 128 (43%) of the patients. The use of chemoprophylaxis was associated with a reduction in risk for tuberculosis (hazard ratio, 0.38; 95% confidence interval, 0.14-1.04; P = 0.05). In a regression model adjusted for baseline CD4 cell count, chemoprophylaxis was associated with longer survival (hazard ratio, 0.24; 95% confidence interval, 0.09-0.65; P = 0.002).

CONCLUSIONS

Anti-tuberculosis chemoprophylaxis was associated with a substantially prolonged survival among purified protein derivative-positive HIV-infected patients in Brazil. These data have important implications for the clinical care of patients with HIV infection in areas of the world with a high prevalence of Mycobacterium tuberculosis infection.

HIV disease progression and V3 serotypes in Brazil: is B different from B-Br?

HIV-1 serotype B-Br (GWGR) is rare in the United States but predominates in Brazil. Differences in prognosis for patients infected with serotype B-Br or serotype B (GPGR) have not been addressed previously. In this prospective cohort study, we compared the rate of disease progression between patients infected with the HIV-1 V3 serotype B or B-Br in Brazil. Progression to AIDS or death was studied by the Kaplan-Meier and Cox proportional hazard methods. Among 445 HIV-infected patients who were tested with a specific enzyme immune assay, 204 (46%) had serotype B-Br infection and 127 (28%) had serotype B infection. Both groups were similar with regard to baseline CD4+ cell count, serum HIV RNA viral load, initial clinical stage, and the proportions who were treated with antiretroviral drugs. Patients with serotype B infection were significantly younger (p = 0.005) and tended to report homosexual behavior more frequently (p = 0.08). Mean follow-up was 30 +/- 13.5 months. During the study period, 41 (32%) patients infected with serotype B and 44 (22%) infected with serotype B-Br developed AIDS (p = 0.03). In a regression model adjusted for age and risk factor for HIV infection, progression to AIDS was faster in patients infected with serotype B (hazard ratio [HR] 1.59; 95% CI, 1.03-2.43; p = 0.03). A similar trend was observed in a model that considered AIDS or death as the outcome (HR, 1.43; 95% CI, 0.95-2.0; p = 0.09). These results suggest that patients infected with closely related HIV-1 serotypes may differ in the rate of progression to AIDS and indicate that serotype should be taken into account in HIV vaccine studies in Brazil.

Purified Trypanosoma cruzi specific glycoprotein for discriminative serological diagnosis of South American trypanosomiasis (Chagas' disease)

Chagas' disease, leishmaniasis, and Trypanosoma rangeli infection are endemic and their distributions overlap in vast regions of South and Central America. Serological cross-reactivities can confuse epidemiological studies of these infections, and their differential diagnosis has been assigned a high priority by the World Health Organisation. A lectin-affinity-purified, 90,000 molecular weight glycoprotein (GP90) is present in the known principal strains (zymodemes) of Trypanosoma cruzi and absent from Leishmania and T rangeli. Patients with T cruzi infection have antibody to GP90, whereas patients with leishmaniasis do not and the two infections can be distinguished in an ELISA system using this antigen. In a mouse model, the same test can differentiate between T cruzi and T rangeli infections. Antigens purified by affinity chromatography clearly provide a practical basis for very precise, even strain-specific, diagnostic tests.

Tuberculosis in HIV programmes in lower-income countries: practices and risk factors

BACKGROUND

Tuberculosis (TB) is a common diagnosis in human immunodeficiency virus (HIV) infected patients on antiretroviral treatment (ART).

OBJECTIVE

To describe TB-related practices in ART programmes in lower-income countries and identify risk factors for TB in the first year of ART.

METHODS

Programme characteristics were assessed using standardised electronic questionnaire. Patient data from 2003 to 2008 were analysed and incidence rate ratios (IRRs) calculated using Poisson regression models.

RESULTS

Fifteen ART programmes in 12 countries in Africa, South America and Asia were included. Chest X-ray, sputum microscopy and culture were available free of charge in respectively 13 (86.7%), 14 (93.3%) and eight (53.3%) programmes. Eight sites (53.3%) used directly observed treatment and five (33.3%) routinely administered isoniazid preventive treatment (IPT). A total of 19 413 patients aged ≥ 16 years contributed 13,227 person-years of follow-up; 1081 new TB events were diagnosed. Risk factors included CD4 cell count (>350 cells/μl vs. <25 cells/μl, adjusted IRR 0.46, 95%CI 0.33-0.64, P < 0.0001), sex (women vs. men, adjusted IRR 0.77, 95%CI 0.68-0.88, P = 0.0001) and use of IPT (IRR 0.24, 95%CI 0.19-0.31, P < 0.0001).

CONCLUSIONS

Diagnostic capacity and practices vary widely across ART programmes. IPT prevented TB, but was used in few programmes. More efforts are needed to reduce the burden of TB in HIV co-infected patients in lower income countries.

Zymodeme and species specificities of monoclonal antibodies raised against Trypanosoma cruzi

A series of hybrid cell lines was generated by the fusion of Sp2/0 myeloma cells with spleen cells from BALB/c mice that had been immunized or infected with Trypanosoma cruzi zymodemes (Z1, Z2, Z3 ). Four immunoglobulin isotypes, IgM, IgG1, IgG2a and IgG3 were represented amongst the monoclonal antibodies secreted by 22 hybridoma clones. On indirect immunofluorescence (IFAT) antibodies bound to flagellum, cytoplasm, cell membrane or stained the whole organism. Two antibodies were epimastigote-specific. Enzyme-linked immunosorbent assays (ELISA) and a dot immunobinding test were used to evaluate the zymodeme and species specificities of 13 antibodies: four reacted with all T. cruzi zymodemes tested, two reacted strongly with all except Z1, two predominantly with Z1, two predominantly with Z2, and three predominantly with Z3 . Two IgM antibodies cross reacted with Trypanosoma rangeli, T. brucei, Leishmania mexicana, L. braziliensis and L. donovani. Five antibodies were used in a preliminary immunobinding test, performed blindly, to compare monoclonal reactivities and zymodeme groups. The results suggested a correlation between the two methods of characterization. Anti-T. cruzi monoclonal antibodies are considered to have important applications to epidemiological studies and the improved diagnosis and prognosis of Chagas' disease.

Willingness to participate in HIV vaccine trials among men who have sex with men in Rio de Janeiro, Brazil. Projeto Praça Onze Study Group

Evaluation of HIV vaccines requires high-risk individuals willing to participate in a vaccine trial. We investigated the willingness to participate in HIV vaccine trials of initially HIV-seronegative homosexual men enrolled in an HIV seroincidence cohort study. Of 815 initially HIV-seronegative participants, 569 (69.8%) reported willingness to participate in an HIV vaccine trial. Altruism was the primary reason given for wanting to participate. Fear of HIV infection from the study's immunizations and a vaccine-induced positive HIV test result were the main reasons for not wanting to participate. Of the 34 study subjects who eventually had HIV seroconversion, 29 (85%) had indicated a willingness to participate. In a univariate analysis, factors associated with willingness to participate included HIV seroconversion during follow-up (odds ratio [OR]. 2.6; p =.04), low educational level (OR, 1.6; p =.005), low family income (p =.02), and exchanging sex for housing, food, or clothing (OR 6.1; p =.005). Students were less likely to be willing to participate in a trial (OR, 0.7; p = .03), as well as those who reported sex at the first encounter (OR, 0.7; p = .05). In a multivariate analysis, low education level, infection with Condyloma, and exchanging sex for housing, food, or clothing were positively associated with willingness to participate, whereas being a student and reporting sex at first encounter were negatively associated. In general, factors indicative of high-risk of HIV infection were associated with a higher willingness. These data demonstrate that this high-risk homosexual male cohort has a high willingness to participate in HIV vaccine trials.

Genetic variation and susceptibilities to protease inhibitors among subtype B and F isolates in Brazil

The genetic variation of the human immunodeficiency virus type 1 (HIV-1) protease gene (prt) permits the classification of HIV-1 strains into five distinct protease subtypes, which follow the gag subtyping patterns. The susceptibilities of non-B-subtype strains to protease inhibitors (PIs) and other antiretroviral drugs remain largely unknown. Subtype F is the main non-B strain contributing to the Brazilian epidemic, accounting for 15 to 20% of these infections. In this work, we report the findings on 81 isolates from PI-naive Brazilian patients collected between 1993 and 1997. In addition, the relevant PI resistance mutations and their phenotypes were determined in vitro for 15 of these patients (B = 9 and F = 6). Among these, the subtype F samples evidenced high sensitivities in vitro to ritonavir and indinavir, with MICs at which 50 and 90% of the isolates are inhibited similar to those of both the Brazilian and the U.S. subtype B isolates. Analysis of the 81 Brazilian prt sequences demonstrated that the subtype F consensus sequence differs from the U.S. and Brazilian subtype B consensus in eight positions (I15V, E35D, M36I, R41K, R57K, Q61N, L63P, and L89M). The frequency of critical PI resistance substitutions (amino acid changes D30N, V82A/F/T, I84V, N88D, and L90M) among Brazilian isolates is very low (mean, 2.5%), and the associated secondary substitutions (amino acid positions 10L, 20K, 36M, 46M, 48G, 54I, 63P, 71A, and 77A) are infrequent. These observations document the relative rarity of resistance to PIs in the treatment of patients infected with HIV-1 subtype F in South America.

Early prognostication of COVID-19 to guide hospitalisation versus outpatient monitoring using a point-of-test risk prediction score

INTRODUCTION

Risk factors of adverse outcomes in COVID-19 are defined but stratification of mortality using non-laboratory measured scores, particularly at the time of prehospital SARS-CoV-2 testing, is lacking.

METHODS

Multivariate regression with bootstrapping was used to identify independent mortality predictors in patients admitted to an acute hospital with a confirmed diagnosis of COVID-19. Predictions were externally validated in a large random sample of the ISARIC cohort (N=14 231) and a smaller cohort from Aintree (N=290).

RESULTS

983 patients (median age 70, IQR 53-83; in-hospital mortality 29.9%) were recruited over an 11-week study period. Through sequential modelling, a five-predictor score termed SOARS (SpO2, Obesity, Age, Respiratory rate, Stroke history) was developed to correlate COVID-19 severity across low, moderate and high strata of mortality risk. The score discriminated well for in-hospital death, with area under the receiver operating characteristic values of 0.82, 0.80 and 0.74 in the derivation, Aintree and ISARIC validation cohorts, respectively. Its predictive accuracy (calibration) in both external cohorts was consistently higher in patients with milder disease (SOARS 0-1), the same individuals who could be identified for safe outpatient monitoring. Prediction of a non-fatal outcome in this group was accompanied by high score sensitivity (99.2%) and negative predictive value (95.9%).

CONCLUSION

The SOARS score uses constitutive and readily assessed individual characteristics to predict the risk of COVID-19 death. Deployment of the score could potentially inform clinical triage in preadmission settings where expedient and reliable decision-making is key. The resurgence of SARS-CoV-2 transmission provides an opportunity to further validate and update its performance.

Significance of the hyperfine interactions in the phase diagram of LiHoxY1-xF4

We consider the quantum magnet at LiHo(x)Y(1-x)F(4) at x = 0.167. Experimentally the spin glass to paramagnet transition in this system was studied as a function of the transverse magnetic field and temperature, showing peculiar features: for example, (i) the spin glass order is destroyed much faster by thermal fluctuations than by the transverse field; and (ii) the cusp in the nonlinear susceptibility signaling the glass state decreases in size at lower temperature. Here we show that the hyperfine interactions of the Ho atom must dominate in this system, and that along with the transverse inter-Ho dipolar interactions they dictate the structure of the phase diagram. The experimental observations are shown to be natural consequences of this.

Gender and survival after AIDS in Rio de Janeiro, Brazil

The relation between gender and survival after a diagnosis of AIDS was studied in a cohort of patients with HIV infection in Rio de Janeiro, Brazil. During the study period, 124 of 617 patients (20%) developed AIDS. Of this group, 91 patients were men and 33 were women. There were no gender related differences regarding the access to antiretroviral therapy or to prophylaxis for Pneumocystis carinii pneumonia. Survival was shorter among women (hazard ratio [HR] = 4.43; p < .001) after adjustment for age and AIDS-defining condition. Adjusting for CD4+ and CD8+ counts reduced the difference between genders (HR = 3.33; p = .017). These results suggest that survival after an AIDS diagnosis may be shorter among women than men in Brazil. Further studies are needed to determine the factors that may be negatively influencing the prognosis of women with AIDS in Brazil.