The natural history of HIV-1 infection in young Thai men after seroconversion

Distinct genetic clusters in HIV-1 CRF01_AE-infected patients induced variable degrees of CD4+ T-cell loss

CRF01_AE strains have been shown to form multiple transmission clusters in China, and some clusters have disparate pathogenicity in Chinese men who have sex with men. This study focused on other CRF01_AE clusters prevalent in heterosexual populations. The CD4+ T-cell counts from both cross-section data in National HIV Molecular Epidemiology Survey and seropositive cohort data were used to evaluate the pathogenicity of the CRF01_AE clusters and other HIV-1 sub-types. Their mechanisms of pathogenicity were evaluated by co-receptor tropisms, predicted by genotyping and confirmed with virus isolate phenotyping, as well as inflammation parameters. Our research elucidated that individuals infected with CRF01_AE clusters 1 and 2 exhibited significantly lower baseline CD4+ T-cell counts and greater CD4+ T-cell loss in cohort follow-up, compared with other HIV-1 sub-types and CRF01_AE clusters. The increased pathogenesis of cluster 1 or 2 was associated with higher CXCR4 tropisms, higher inflammation/immune activation, and increased pyroptosis. The protein structure modeling analysis revealed that the envelope V3 loop of clusters 1 and 2 viruses is favorable for CXCR4 co-receptor usage. Imbedded with the most mutating reverse transcriptase, HIV-1 is one of the most variable viruses. CRF01_AE clusters 1 and 2 have been found to have evolved into more virulent strains in regions with predominant heterosexual infections. The virulent strains increased the pressure for early diagnosis and treatment in HIV patients. To save more lives, HIV-1 surveillance systems should be upgraded from serology and genotyping to phenotyping, which could support precision interventions for those infected by virulent viruses.

IMPORTANCE

Retroviruses swiftly adapt, employing error-prone enzymes for genetic and phenotypic evolution, optimizing survival strategies, and enhancing virulence levels. HIV-1 CRF01_AE has persistently undergone adaptive selection, and cluster 1 and 2 infections display lower counts and fast loss of CD4+ T cells than other HIV-1 sub-types and CRF01_AE clusters. Its mechanisms are associated with increased CXCR4 tropism due to an envelope structure change favoring a tropism shift from CCR5 to CXCR4, thereby shaping viral phenotype features and impacting pathogenicity. This underscores the significance of consistently monitoring HIV-1 genetic evolution and phenotypic transfer to see whether selection bias across risk groups alters the delicate balance of transmissible versus toxic trade-offs, since virulent strains such as CRF01_AE clusters 1 and 2 could seriously compromise the efficacy of antiviral treatment. Only through such early warning and diagnostic services can precise antiviral treatments be administered to those infected with more virulent HIV-1 strains.

Association of aflatoxin B1 levels with mean CD4 cell count and uptake of ART among HIV infected patients: A prospective study

Background

Aflatoxin suppresses cellular immunity and accentuates HIV-associated changes in T- cell phenotypes and B- cells.

Objective

This prospective study was conducted to examine the association of aflatoxin levels with CD4 T-cell count and antiretroviral therapy uptake over time.

Methods

Sociodemographic and food data were collected from antiretroviral therapy naïve HIV-infected patients. CD4+ counts were collected from participants’ medical records. Plasma samples were tested for aflatoxin B₁ albumin adducts, hepatitis B surface antigen, and HIV viral load. Participants were separated into high and low aflatoxin groups based on the median aflatoxin B₁ albumin adduct level of 10.4 pg/ml for data analysis.

Results

Participants with high aflatoxin B₁ albumin adduct levels had lower mean CD4 at baseline and at each follow-up period. Adjusted multivariable logistic regression analysis showed that higher baseline aflatoxin B₁ adduct levels were associated with statistically significant lower CD4 counts (est = -66.5, p = 0.043). Not starting ART and low/middle socioeconomic status were associated with higher CD4 counts (est = 152.2, p<0.001) and (est = 86.3, p = 0.027), respectively.

Conclusion

Consistent correlations of higher aflatoxin B₁ adduct levels with lower CD4 over time indicate that there is an independent early and prolonged effect of aflatoxin on CD4 even with the initiation of antiretroviral therapy. The prospective study design, evaluation of baseline and follow-up measures, extensive control for potential confounders, and utilization of objective measures of aflatoxin exposure and CD4 count provide compelling evidence for a strong epidemiologic association that deserves careful attention in HIV care and treatment programs.

Disease progression and mortality with untreated HIV infection: evidence synthesis of HIV seroconverter cohorts, antiretroviral treatment clinical cohorts and population-based survey data

Introduction

Model‐based estimates of key HIV indicators depend on past epidemic trends that are derived based on assumptions about HIV disease progression and mortality in the absence of antiretroviral treatment (ART). Population‐based HIV Impact Assessment (PHIA) household surveys conducted between 2015 and 2018 found substantial numbers of respondents living with untreated HIV infection. CD4 cell counts measured in these individuals provide novel information to estimate HIV disease progression and mortality rates off ART.

Methods

We used Bayesian multi‐parameter evidence synthesis to combine data on (1) cross‐sectional CD4 cell counts among untreated adults living with HIV from 10 PHIA surveys, (2) survival after HIV seroconversion in East African seroconverter cohorts, (3) post‐seroconversion CD4 counts and (4) mortality rates by CD4 count predominantly from European, North American and Australian seroconverter cohorts. We used incremental mixture importance sampling to estimate HIV natural history and ART uptake parameters used in the Spectrum software. We validated modelled trends in CD4 count at ART initiation against ART initiator cohorts in sub‐Saharan Africa.

Results

Median untreated HIV survival decreased with increasing age at seroconversion, from 12.5 years [95% credible interval (CrI): 12.1–12.7] at ages 15–24 to 7.2 years (95% CrI: 7.1–7.7) at ages 45–54. Older age was associated with lower initial CD4 counts, faster CD4 count decline and higher HIV‐related mortality rates. Our estimates suggested a weaker association between ART uptake and HIV‐related mortality rates than previously assumed in Spectrum. Modelled CD4 counts in untreated people living with HIV matched recent household survey data well, though some intercountry variation in frequencies of CD4 counts above 500 cells/mm³ was not explained. Trends in CD4 counts at ART initiation were comparable to data from ART initiator cohorts. An alternate model that stratified progression and mortality rates by sex did not improve model fit appreciably.

Conclusions

Synthesis of multiple data sources results in similar overall survival as previous Spectrum parameter assumptions but implies more rapid progression and longer survival in lower CD4 categories. New natural history parameter values improve consistency of model estimates with recent cross‐sectional CD4 data and trends in CD4 counts at ART initiation.

Disparate impact on CD4 T cell count by two distinct HIV-1 phylogenetic clusters from the same clade

Past studies on HIV-1 evolution were mainly at the genetic level. This study provides well-matched genotype and phenotype data and demonstrates the disparate pathogenicity of two major CRF01_AE clusters. While CRF01_AE cluster 4 and cluster 5 are associated with the men-who-have-sex-with-men (MSM) route of transmission, cluster 4 but not cluster 5 causes a low CD4 count, which is associated with the higher prevalence CXCR4 viruses in cluster 4. The higher CXCR4 use tendency in cluster 4 is derived from its unique V3 loop favoring CXCR4 binding. This study demonstrates disparate HIV-1 phenotypes between different phylogenetic clusters. It is important to monitor HIV-1 evolution at both the genotype and phenotype level to identify and control more pathogenic HIV-1 strains.

HIV-1 evolved into various genetic subtypes and circulating recombinant forms (CRFs) in the global epidemic. The same subtype or CRF is usually considered to have similar phenotype. Being one of the world’s major CRFs, CRF01_AE infection was reported to associate with higher prevalence of CXCR4 (X4) viruses and faster CD4 decline. However, the underlying mechanisms remain unclear. We identified eight phylogenetic clusters of CRF01_AE in China and hypothesized that they may have different phenotypes. In the National HIV Molecular Epidemiology Survey, we discovered that people infected by CRF01_AE cluster 4 had significantly lower CD4 counts (391 vs. 470, P < 0.0001) and higher prevalence of X4-using viruses (17.1% vs. 4.4%, P < 0.0001) compared with those infected by cluster 5. In an MSM cohort, X4-using viruses were only isolated from seroconvertors in cluster 4, which was associated with low a CD4 count within the first year of infection (141 vs. 440, P = 0.003). Using a coreceptor binding model, we identified unique V3 signatures in cluster 4 that favor CXCR4 use. We demonstrate that the HIV-1 phenotype and pathogenicity can be determined at the phylogenetic cluster level in the same subtype. Since its initial spread to humans from chimpanzees, estimated to be the first half of the 20th century, HIV-1 continues to undergo rapid evolution in larger and more diverse populations. The divergent phenotype evolution of two major CRF01_AE clusters highlights the importance of monitoring the genetic evolution and phenotypic shift of HIV-1 to provide early warning of the appearance of more pathogenic strains.

Association between HIV genotype, viral load and disease progression in a cohort of Thai men who have sex with men with estimated dates of HIV infection

BACKGROUND

Differences between HIV genotypes may affect HIV disease progression. We examined infecting HIV genotypes and their association with disease progression in a cohort of men who have sex with men with incident HIV infection in Bangkok, Thailand.

METHODS

We characterized the viral genotype of 189 new HIV infections among MSM identified between 2006-2014 using hybridization and sequencing. Plasma viral load (PVL) was determined by PCR, and CD4+ T-cell counts were measured by flow cytometry. We used Generalized Estimating Equations to examine factors associated with changes in CD4+ T-cell counts. Factors associated with immunologic failure were analyzed using Cox proportional hazard models.

RESULTS

Among 189 MSM, 84% were infected with CRF01_AE, 11% with recombinant B/CRF01_AE and 5% with subtype B. CD4+ T-cell decline rates were 68, 65, and 46 cells/μL/year for CRF01_AE, recombinants, and subtype B, respectively, and were not significantly different between HIV subtypes. CD4+ T-cell decline rate was significantly associated with baseline PVL and CD4+ T-cell counts (p <0.001). Progression to immunologic failure was associated with baseline CD4+ T-cell ≤ 500 cells/μL (AHR 1.97; 95% CI 1.14-3.40, p = 0.015) and PVL > 50,000 copies/ml (AHR 2.03; 1.14-3.63, p = 0.017). There was no difference in time to immunologic failure between HIV subtypes.

CONCLUSION

Among HIV-infected Thai MSM, low baseline CD4+ T-cell and high PVL are associated with rapid progression. In this cohort, no significant difference in CD4+ T-cell decline rate or time to immunologic failure was seen between CRF01_AE and other infecting HIV subtypes.

Patient-Initiated Repackaging of Antiretroviral Therapy, Viral Suppression and Drug Resistance

Patient-initiated repackaging of antiretroviral therapy (ART) refers to removal of ART medications from their original manufacturer's containers, and putting them into alternative containers. This behavior may be triggered by stigma associated with HIV infection, and may impact patient outcomes. We assessed association between patient initiated repackaging of ART and failure to achieve viral suppression (FVS) in a sample of 450 HIV-infected adults (≥8 years) on first line ART for ≥6 months. FVS was defined as a plasma HIV RNA level ≥400 copies/mL. A total of 197 (43.7%) patients reported repackaging their ART medications. One hundred ninety-one patients (42.4%) failed to suppress and FVS was associated with medication repackaging [adjusted odds ratio (aOR), 2.2; 95% CI 1.4-3.3.] Adherence to ART was also associated with FVS (aOR; 0.4; 95% CI 0.2-0.6.). Benefits of retaining drugs in their original packaging along with adherence to ART should be emphasized to reduce the risk of FVS.

Joint estimation of CD4+ cell progression and survival in untreated individuals with HIV-1 infection

Objective:

We compiled the largest dataset of seroconverter cohorts to date from 25 countries across Africa, North America, Europe, and Southeast/East (SE/E) Asia to simultaneously estimate transition rates between CD4⁺ cell stages and death, in antiretroviral therapy (ART)-naive HIV-1-infected individuals.

Design:

A hidden Markov model incorporating a misclassification matrix was used to represent natural short-term fluctuations and measurement errors in CD4⁺ cell counts. Covariates were included to estimate the transition rates and survival probabilities for each subgroup.

Results:

The median follow-up time for 16 373 eligible individuals was 4.1 years (interquartile range 1.7–7.1), and the mean age at seroconversion was 31.1 years (SD 8.8). A total of 14 525 individuals had recorded CD4⁺ cell counts pre-ART, 1885 died, and 6947 initiated ART. Median (interquartile range) survival for men aged 20 years at seroconversion was 13.0 (12.4–13.4), 11.6 (10.9–12.3), and 8.3 years (7.9–8.9) in Europe/North America, Africa, and SE/E Asia, respectively. Mortality rates increase with age (hazard ratio 2.22, 95% confidence interval 1.84–2.67 for >45 years compared with <25 years) and vary by region (hazard ratio 2.68, 1.75–4.12 for Africa and 1.88, 1.50–2.35 for Asia compared with Europe/North America). CD4⁺ cell decline was significantly faster in Asian cohorts compared with Europe/North America (hazard ratio 1.45, 1.36–1.54).

Conclusion:

Mortality and CD4⁺ cell progression rates exhibited regional and age-specific differences, with decreased survival in African and SE/E Asian cohorts compared with Europe/North America and in older age groups. This extensive dataset reveals heterogeneities between regions and ages, which should be incorporated into future HIV models.

The impact of HCV therapy in a high HIV-HCV prevalence population: A modeling study on people who inject drugs in Ho Chi Minh City, Vietnam

BACKGROUND

Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) coinfection is a major global health problem especially among people who inject drugs (PWID), with significant clinical implications. Mathematical models have been used to great effect to shape HIV care, but few have been proposed for HIV/HCV.

METHODS

We constructed a deterministic compartmental ODE model that incorporated layers for HIV disease progression, HCV disease progression and PWID demography. Antiretroviral therapy (ART) and Methadone Maintenance Therapy (MMT) scale-ups were modeled as from 2016 and projected forward 10 years. HCV treatment roll-out was modeled beginning in 2026, after a variety of MMT scale-up scenarios, and projected forward 10 years.

RESULTS

Our results indicate that scale-up of ART has a major impact on HIV though not on HCV burden. MMT scale-up has an impact on incidence of both infections. HCV treatment roll-out has a measurable impact on reductions of deaths, increasing multifold the mortality reductions afforded by just ART/MMT scale-ups.

CONCLUSION

HCV treatment roll-out can have major and long-lasting effects on averting PWID deaths on top of those averted by ART/MMT scale-up. Efficient intervention scale-up of HCV alongside HIV interventions is critical in Vietnam.

Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses

HIV-1-infected cells presenting envelope glycoproteins (Env) in the CD4-bound conformation on their surface are preferentially targeted by antibody-dependent cellular-mediated cytotoxicity (ADCC). HIV-1 has evolved sophisticated mechanisms to avoid the exposure of Env ADCC epitopes by downregulating CD4 and by limiting the overall amount of Env on the cell surface. In HIV-1, substitution of large residues such as histidine or tryptophan for serine 375 (S375H/W) in the gp120 Phe 43 cavity, where Phe 43 of CD4 contacts gp120, results in the spontaneous sampling of an Env conformation closer to the CD4-bound state. While residue S375 is well conserved in the majority of group M HIV-1 isolates, CRF01_AE strains have a naturally occurring histidine at this position (H375). Interestingly, CRF01_AE is the predominant circulating strain in Thailand, where the RV144 trial took place. In this trial, which resulted in a modest degree of protection, ADCC responses were identified as being part of the correlate of protection. Here we investigate the influence of the Phe 43 cavity on ADCC responses. Filling this cavity with a histidine or tryptophan residue in Env with a natural serine residue at this position (S375H/W) increased the susceptibility of HIV-1-infected cells to ADCC. Conversely, the replacement of His 375 by a serine residue (H375S) within HIV-1 CRF01_AE decreased the efficiency of the ADCC response. Our results raise the intriguing possibility that the presence of His 375 in the circulating strain where the RV144 trial was held contributed to the observed vaccine efficacy.IMPORTANCE HIV-1-infected cells presenting Env in the CD4-bound conformation on their surface are preferentially targeted by ADCC mediated by HIV-positive (HIV⁺) sera. Here we show that the gp120 Phe 43 cavity modulates the propensity of Env to sample this conformation and therefore affects the susceptibility of infected cells to ADCC. CRF01_AE HIV-1 strains have an unusual Phe 43 cavity-filling His 375 residue, which increases the propensity of Env to sample the CD4-bound conformation, thereby increasing susceptibility to ADCC.

Histidine 375 Modulates CD4 Binding in HIV-1 CRF01_AE Envelope Glycoproteins

The envelope glycoproteins (Envs) from human immunodeficiency virus type 1 (HIV-1) mediate viral entry. The binding of the HIV-1 gp120 glycoprotein to CD4 triggers conformational changes in gp120 that allow high-affinity binding to its coreceptors. In contrast to all other Envs from the same phylogenetic group, M, which possess a serine (S) at position 375, those from CRF01_AE strains possess a histidine (H) at this location. This residue is part of the Phe43 cavity, where residue 43 of CD4 (a phenylalanine) engages with gp120. Here we evaluated the functional consequences of replacing this residue in two CRF01_AE Envs (CM244 and 92TH023) by a serine. We observed that reversion of amino acid 375 to a serine (H375S) resulted in a loss of functionality of both CRF01_AE Envs as measured by a dramatic loss in infectivity and ability to mediate cell-to-cell fusion. While no effects on processing or trimer stability of these variants were observed, decreased functionality could be linked to a major defect in CD4 binding induced by the replacement of H375 by a serine. Importantly, mutations of residues 61 (layer 1), 105 and 108 (layer 2), and 474 to 476 (layer 3) of the CRF01_AE gp120 inner domain layers to the consensus residues present in group M restored CD4 binding and wild-type levels of infectivity and cell-to-cell fusion. These results suggest a functional coevolution between the Phe43 cavity and the gp120 inner domain layers. Altogether, our observations describe the functional importance of amino acid 375H in CRF01_AE envelopes.

IMPORTANCE

A highly conserved serine located at position 375 in group M is replaced by a histidine in CRF01_AE Envs. Here we show that H375 is required for efficient CRF01_AE Env binding to CD4. Moreover, this work suggests that specific residues of the gp120 inner domain layers have coevolved with H375 in order to maintain its ability to mediate viral entry.

Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

HLA Class I Alleles Associated with Mortality in Thai Military Recruits with HIV-1 CRF01_AE Infection

In HIV-1-infected patients, variation at the HLA class I locus is associated with disease progression, but few studies have assessed the influence of HLA alleles on HIV-1 CRF01_AE infection, which is dominant in Thailand. We hypothesized that alleles predicted to confer more effective immune responses, such as HLA-B*46, would protect against disease progression. HLA typing was performed on HIV-1 incident cases surviving until 1998-1999 and HIV-1-negative matched controls from Thai army cohorts enrolled between 1991 and 1995. We assessed associations between class I alleles and disease progression subsequent to HLA typing. Ninety-nine HIV-1-incident cases were followed for a median of 3.7 years after HLA typing; during this time, 58 participants died. Two alleles were associated with mortality: HLA B*51 was protective (3-year survival B*51(pos) vs. B*51(neg): 75% vs. 52%; p = 0.034) whereas Cw*04 was deleterious (3-year survival Cw*04(pos) vs. Cw*04(neg): 39% vs. 60%; p = 0.027). HLA-B*46 was not associated with disease progression. Alleles present at different frequencies in HIV-1-incident compared with HIV-1-negative men included HLA-A*02:03, B*35, B*15, and C*08. 1. In conclusion in this Thai army cohort, HLA-B*51 was associated with lower mortality, confirming that this allele, which is protective in clade B HIV-1 infection, has a similar effect on HIV CRF01_AE infection. The deleterious effect of HLA-Cw*04 must be interpreted with caution because it may be in linkage disequilibrium with disease-susceptible HLA-B alleles. We did not find that HLA-B*46 was protective. These findings may inform vaccine development for areas of the world in which HIV-1 CRF01_AE infection is prevalent.

Disease progression of HIV-1 infection in symptomatic and asymptomatic seroconverters in Osaka, Japan: a retrospective observational study

Background

Estimates of the interval from HIV-1 infection to disease progression may be affected by selection bias, and data concerning asymptomatic early seroconverters are limited. We examined the interval until disease progression in HIV-1 seroconverters in whom the timing of infection could be estimated within 1 year before diagnosis.

Methods

Subjects included newly diagnosed patients at Osaka National Hospital between 2003 and 2010 who had either (1) symptomatic acute HIV-1 infection with a negative or intermediate reaction on Western blotting and a positive reaction on an HIV RNA test (symptomatic acute group) or (2) a positive reaction on Western blotting at diagnosis and a <1-year interval from the last negative HIV test until the first positive test. The latter was divided into symptomatic recent or asymptomatic recent groups based on the presence or absence, respectively, of any transient fever between the last negative and first positive tests. Disease progression was defined as a fall in the CD4 count to <350 cells/microL on 2 consecutive tests, the start of anti-HIV therapy, or the onset of AIDS-indicator diseases. Information was retrospectively collected from medical records.

Results

Subjects included 210 patients: 91 in the symptomatic acute group, 72 in the symptomatic recent group, and 47 in the asymptomatic recent group. In the symptomatic acute (0.8 years) and symptomatic recent (2.2 years) groups, the Kaplan-Meier estimate of median interval until disease progression was significantly shorter than that in the asymptomatic recent group (2.9 years). Multivariate analysis by Cox’s proportional hazards test showed that the symptomatic acute group (vs. asymptomatic recent group: hazard ratio: 1.93; 95% confidence interval: 1.14–3.36; p = 0.0140) and a baseline CD4 count of <400 cells/microL (hazard ratio: 3.88; 95% confidence interval: 2.57–5.96; p < 0.0001) were independent prognostic factors associated with early disease progression.

Conclusions

Symptomatic seroconversion was associated with early disease progression. Furthermore, the estimated median interval until the CD4 count was <350 cells/microL was only 2.9 years even in patients with asymptomatic seroconversion. These results suggest the importance of early diagnosis in early seroconverters.

CRF01_AE subtype is associated with X4 tropism and fast HIV progression in Chinese patients infected through sexual transmission

BACKGROUND

The molecular epidemiology of the HIV-1 CRF01_AE subtype as a risk factor for fast HIV-1 progression remains poorly understood.

METHODS

We analyzed HIV-1 tropism by utilizing samples from 201 treatment-naive patients in our multicenter cohort (12 research centers in different provinces of China). Tropism was determined by V3 loop sequencing. Data from 235 treatment-naive patients infected sexually (including aforementioned 201 patients) in this cohort with date of estimated seroconversion (EDS) were retrospectively evaluated. Median time from EDS to AIDS was analyzed by Kaplan-Meier curves. Hazard ratios were determined by Cox proportional model.

RESULTS

CRF01_AE subtype was predominant (46.0%), especially in the MSM group. Further analysis revealed that the proportion of X4 tropism was higher in the CRF01_AE subtype (45.5%) than in others (C/CRF07_BC/CRF08_BC, 4.3%; B, 6.1%; P <0.001). CRF01_AE subtype was associated with faster progression from EDS to AIDS (4.8 vs. 6.4 years, P = 0.018) compared with non-CRF01_AE subtypes. In a multivariate model, the adjusted hazard ratio (aHR) of CRF01_AE was 1.42 (95% confidence interval, CI 0.99-2.03, P = 0.057), independent of HIV-1 viral load; it was also associated with fast progression to advanced immunodeficiency (aHR, 1.81, 95% CI 1.03-3.18, P = 0.038).

CONCLUSION

CRF01_AE, a predominant HIV-1 subtype in Chinese HIV-1 sexually infected patients, tends to be associated with fast progression to AIDS and advanced immunodeficiency, which might be ascribed to high proportion of X4 tropism. Further investigation of these risk factors may have significant implications to clinical practice and policy-making.

Biomedical HIV prevention research and epidemic control in Thailand: two sides of the same coin

For a country with a moderate adult HIV prevalence of just over 1% in 2012, Thailand is widely perceived as having made some extraordinary contributions to the global management of the HIV/AIDS pandemic. It has been promoted as a model of effective HIV control and applauded for its leadership in providing access to antiretroviral treatment. Thailand has also received international recognition for its contribution to biomedical HIV prevention research, which is generally perceived as exceptional. In this paper, Thailand's global role model function as an example of effective HIV/AIDS control and high-quality biomedical HIV prevention research is re-evaluated against the background of currently available data and more recent insights. The results indicate that Thailand's initial response in raising the level of the political significance of HIV/AIDS was indeed extraordinary, which probably prevented a much larger epidemic from occurring. However, this response transpired in unusual extraconstitutional circumstances and its effectiveness declined once the country returned to political normalcy. Available data confirm the country's more than exceptional contribution to biomedical HIV prevention research. Thailand has made a huge contribution to the global management and control of the HIV/AIDS pandemic.

Comparison of the health-related quality of life, CD4 count and viral load of AIDS patients and people with HIV who have been on treatment for 12 months in rural South Africa

This study compared the level of CD4 count, viral load and health-related quality of life (HRQOL) between treatment-naïve AIDS patients and a cohort of people living with HIV who have been on treatment for 12 months. This study is based on a secondary data analysis of the records of 642 people with HIV consisting of 311 treatment-naïve AIDS patients and 331 people with HIV who have been on treatment for 12 months. The study findings are mostly presented in tables and analysed using the t-test to compare HRQOL scores, CD4 count and viral load in the two groups. The study generally noted poor financial capacity and low activity tolerance among the participants. Significant changes were noted in all the domains of HRQOL compared between the treatment-naïve patients and the 12 months treatment cohort. In the same manner, the median CD4 cell count and viral load differed significantly between both groups. The treatment-naïve and the 12 months treatment cohorts consistently reported much lower quality of life scores in the level of dependence domain which includes the measures of mobility, activity of daily living, dependence on medication and work capacity. There were little or no associations between the biomedical markers (CD4 count and viral load) and HRQOL indicators. However, the quality of life tended to increase with increase in the CD4 cell count. The poor to no association between the biomedical markers and HRQOL indicators show that these cannot be direct proxies of each other and that the CD4 cell count and viral load alone may be inadequate eligibility criteria for social support.

Human immunodeficiency virus type 1 in Ireland: phylogenetic evidence for risk group-specific subepidemics

HIV genetic diversity may have an impact on viral pathogenesis, transmission, response to treatment, and vaccine development. Public health surveillance that monitors the frequency and variety of HIV subtypes in a particular region or patient group is vital to successfully control the pandemic. We present the first comprehensive report on HIV diversity in Ireland. This study comprised all new HIV-1 diagnoses that were confirmed in the National Virus Reference Laboratory, University College Dublin, from January 2004 to December 2008. HIV 1 protease and reverse transcriptase sequences were generated using the Siemens Trugene HIV 1 Genotyping System. Subtypes were determined using web-based genotyping tools. There were 1579 new diagnoses [615 (39%) female and 964 (61%) male], of which 1060 had HIV-1 RNA specimens available for sequencing. Of sequenced samples, HIV-1 subtype B accounted for 50% overall, decreasing from 55.1% in 2004 to 49.5% in 2008. In addition, subtype B accounted for more than 80% of Irish-born individuals and more than 90% of Irish-born injection drug users and men who have sex with men. Subtype C was the second most prevalent in the overall cohort, accounting for 25%, although it accounted for only 6.1% of Irish-born individuals, with no evidence of in country transmission. The prevalence of non-subtype B HIV-1 infection in Ireland is increasing. However, these appear primarily to be imported infections not yet circulating within traditional Irish risk groups. Enhanced HIV-1 molecular epidemiology surveillance is required to monitor the spread of HIV-1, to inform future public health policy, and to ultimately control the HIV-1 epidemic in Ireland.

Will changes in gay men's sexual behavior reduce syphilis rates?

BACKGROUND

Reducing rates of partner change and increasing condom usage among gay men are obvious targets for potentially reducing syphilis transmission among gay men.

METHODS

We developed an agent-based stochastic model to examine syphilis transmission among a population of gay men, representative of gay men in Australia. This model was used to explore the potential impact of changes in sexual behavior over 1 month, 3 month, and indefinite time frames on syphilis epidemics.

RESULTS

Simulations of interventions showed that short-term reductions in rates of partner change and increased condom use would have negligible impact on the long-term trends of syphilis epidemics. If no interventions are introduced, then the model forecasts that the syphilis prevalence in the population could continue to rise, with an increase of 80% in the number of men infected with syphilis during the next decade. However, if changes in sexual behavior are maintained in the long-term, then syphilis epidemics can be mitigated. If condom use is sustained at 80% in partnerships that are HIV discordant or of unknown status, then the prevalence of syphilis is estimated to decrease by 9% over 10 years. Similarly, if partner acquisition rates decrease by 25%, then there will be a 22% reduction in syphilis prevalence.

CONCLUSIONS

Interventions promoting partner reduction or increased condom use would be ineffective in the short-term, and would have limited prospects for success in the long-term unless very large changes in behavior are sustained. Complementary social research indicates that such long-term changes in behavior are unlikely to be adopted, and therefore other intervention strategies need to be developed to reduce syphilis among gay men.

Acute retroviral syndrome and high baseline viral load are predictors of rapid HIV progression among untreated Argentinean seroconverters

Background

Diagnosis of primary HIV infection (PHI) has important clinical and public health implications. HAART initiation at this stage remains controversial.

Methods

Our objective was to identify predictors of disease progression among Argentinean seroconverters during the first year of infection, within a multicentre registry of PHI-patients diagnosed between 1997 and 2008. Cox regression was used to analyze predictors of progression (LT-CD4 < 350 cells/mm³, B, C events or death) at 12 months among untreated patients.

Results

Among 134 subjects, 74% presented with acute retroviral syndrome (ARS). Seven opportunistic infections (one death), nine B events, and 10 non-AIDS defining serious events were observed. Among the 92 untreated patients, 24 (26%) progressed at 12 months versus three (7%) in the treated group (p = 0.01). The 12-month progression rate among untreated patients with ARS was 34% (95% CI 22.5-46.3) versus 13% (95% CI 1.1-24.7) in asymptomatic patients (p = 0.04). In univariate analysis, ARS, baseline LT-CD4 < 350 cells/mm³, and baseline and six-month viral load (VL) > 100,000 copies/mL were associated with progression. In multivariate analysis, only ARS and baseline VL > 100,000 copies/mL remained independently associated; HR: 8.44 (95% CI 0.97-73.42) and 9.44 (95% CI 1.38-64.68), respectively.

Conclusions

In Argentina, PHI is associated with significant morbidity. HAART should be considered in PHI patients with ARS and high baseline VL to prevent disease progression.

Changes in the distribution of HIV type 1 subtypes D and A in Rakai District, Uganda between 1994 and 2002

HIV-1 subtype D (HIV-1D) progresses to disease faster and has lower transmissibility than subtype A (HIV-1A). We examined whether these differences could lead to a population level change in the distribution of these subtypes over time. HIV-1 viral RNA was extracted from stored serum samples from HIV-positive subjects participating in a population-based cohort study in Rakai, Uganda in 1994 and 2002. Portions of the viral proteins gag and gp41 were sequenced and subtyped. HIV-1 subtype assignments were generated for 773 subjects in 1994 and 812 subjects in 2002. The change in subtype distribution of the population as a whole as well as quartile age groups were examined for significant changes using a linear model. There was a significant decrease in the proportion of subjects infected with HIV-1D from 70.2% to 62.4% and a significant increase in subjects infected with HIV-1A from 16.7% to 23.3% over the 8-year period (p = 0.005). The most marked changes in proportion of HIV-1D and A were seen in the younger individuals (<25 and 25-30 years; p < 0.05). The percentages of subjects infected with HIV-1C and recombinant subtypes did not change significantly. Over this 8-year period, the overall viral population in this region evolved toward the less virulent HIV-1A strain, most likely as a consequence of the faster disease progression and lower transmissibility of HIV-1D.

The welfare costs of HIV/AIDS in eastern Europe: an empirical assessment using the economic value-of-life approach

Based on the aggregation of individual willingness-to-pay for a statistical life, we calibrate an inter-temporal optimisation model to determine the aggregate welfare loss from HIV/AIDS in 25 Eastern European countries. Assuming a discount rate of 3%, we find a total welfare loss for the whole region that exceeds US $800 billion, approximately 10% of the region's annual GDP between 1995 and 2001. Although prevalence and incidence rates diverge sharply between countries-with central Europe far less affected than major countries in the Commonwealth of Independent States and the Baltics-the epidemic is likely to spread to all countries unless a coherent strategy of prevention and treatment is backed up by substantial increases in healthcare investments. The sheer size of this task and the international nature of the epidemic render this one of the most important current challenges for all of Europe.

Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men

BACKGROUND

We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates?

METHODS

We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources.

RESULTS

We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14-0.28.

CONCLUSIONS

The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.

The Spectrum projection package: improvements in estimating mortality, ART needs, PMTCT impact and uncertainty bounds

BACKGROUND

The approach to national and global estimates of HIV/AIDS used by UNAIDS starts with estimates of adult HIV prevalence prepared from surveillance data using either the Estimation and Projection Package (EPP) or the Workbook. Time trends of prevalence are transferred to Spectrum to estimate the consequences of the HIV/AIDS epidemic, including the number of people living with HIV, new infections, AIDS deaths, AIDS orphans, treatment needs and the impact of treatment on survival.

METHODS

The UNAIDS Reference Group on Estimates, Modelling and Projections regularly reviews new data and information needs and recommends updates to the methodology and assumptions used in Spectrum. The latest update to Spectrum was used in the 2007 round of global estimates.

RESULTS

Several new features have been added to Spectrum in the past two years. The structure of the population was reorganised to track populations by HIV status and treatment status. Mortality estimates were improved by the adoption of new approaches to estimating non-AIDS mortality by single age, and the use of new information on survival with HIV in non-treated cohorts and on the survival of patients on antiretroviral treatment (ART). A more detailed treatment of mother-to-child transmission of HIV now provides more prophylaxis and infant feeding options. New procedures were implemented to estimate the uncertainty around each of the key outputs.

CONCLUSIONS

The latest update to the Spectrum program is intended to incorporate the latest research findings and provide new outputs needed by national and international planners.

Duration from seroconversion to eligibility for antiretroviral therapy and from ART eligibility to death in adult HIV-infected patients from low and middle-income countries: collaborative analysis of prospective studies

BACKGROUND

Estimation of the number of people in need of antiretroviral therapy (ART) in resource-limited settings requires information on the time from seroconversion to ART eligibility and from ART eligibility to death.

OBJECTIVES

To estimate duration from seroconversion to different ART eligibility criteria and from ART eligibility to death in HIV-infected adults in low-income and middle-income countries.

METHODS

Participants with documented seroconversion from five cohorts (two cohorts from Uganda, two from Thailand and one from Côte d'Ivoire) were analysed. We used Weibull survival models and Bayesian simulation methods to model true (unobserved) first time of treatment eligibility. We set a consistency constraint so that the mean duration from seroconversion to death was equal to the mean from seroconversion to ART eligibility plus the mean from eligibility to death.

RESULTS

We analysed data from 2072 participants, 16 157 person-years of follow-up and 794 deaths. For the criterion CD4 T-lymphocyte count <200 cells x10(6)/l, the median duration from seroconversion to ART eligibility was 6.1 years (95% credibility interval 3.3-10.4) for all studies and 7.6 years (95% credibility interval 3.4-15.2) for all but the Thai cohorts. Corresponding estimates for the time from CD4 T-lymphocyte count <200 cells x10(6)/l to death were 2.1 years (0.7-4.8) and 2.7 years (0.8-8.4). When including all cohorts, the mean time from serconversion to CD4 T-lymphocyte count <200 cells x10(6)/l and from CD4 T-lymphocyte count <200 cells x10(6)/l to death represented 66% (38-87%) and 34% (13-62%), respectively of the total survival time.

CONCLUSIONS

The duration of different ART eligibility criteria to death was longer than the estimates used in previous calculations of the number of people needing ART. However, uncertainty in estimates was considerable and heterogeneity across cohorts important.

Relation between HIV viral load and infectiousness: a model-based analysis

BACKGROUND

A consensus statement released on behalf of the Swiss Federal Commission for HIV/AIDS suggests that people receiving effective antiretroviral therapy-ie, those with undetectable plasma HIV RNA (<40 copies per mL)-are sexually non-infectious. We analysed the implications of this statement at a population level.

METHODS

We used a simple mathematical model to estimate the cumulative risk of HIV transmission from effectively treated HIV-infected patients (HIV RNA <10 copies per mL) over a prolonged period. We investigated the risk of unprotected sexual transmission per act and cumulatively over many exposures, within couples initially discordant for HIV status.

FINDINGS

Assuming that each couple had 100 sexual encounters per year, the cumulative probability of transmission to the serodiscordant partner each year is 0.0022 (uncertainty bounds 0.0008-0.0058) for female-to-male transmission, 0.0043 (0.0016-0.0115) for male-to-female transmission, and 0.043 (0.0159-0.1097) for male-to-male transmission. In a population of 10 000 serodiscordant partnerships, over 10 years the expected number of seroconversions would be 215 (80-564) for female-to-male transmission, 425 (159-1096) for male-to-female transmission, and 3524 (1477-6871) for male-to-male transmission, corresponding to an increase in incidence of four times compared with incidence under current rates of condom use.

INTERPRETATION

Our analyses suggest that the risk of HIV transmission in heterosexual partnerships in the presence of effective treatment is low but non-zero and that the transmission risk in male homosexual partnerships is high over repeated exposures. If the claim of non-infectiousness in effectively treated patients was widely accepted, and condom use subsequently declined, then there is the potential for substantial increases in HIV incidence.

FUNDING

Australian Research Council.

Estimating incidence from prevalence in generalised HIV epidemics: methods and validation

BACKGROUND

HIV surveillance of generalised epidemics in Africa primarily relies on prevalence at antenatal clinics, but estimates of incidence in the general population would be more useful. Repeated cross-sectional measures of HIV prevalence are now becoming available for general populations in many countries, and we aim to develop and validate methods that use these data to estimate HIV incidence.

METHODS AND FINDINGS

Two methods were developed that decompose observed changes in prevalence between two serosurveys into the contributions of new infections and mortality. Method 1 uses cohort mortality rates, and method 2 uses information on survival after infection. The performance of these two methods was assessed using simulated data from a mathematical model and actual data from three community-based cohort studies in Africa. Comparison with simulated data indicated that these methods can accurately estimates incidence rates and changes in incidence in a variety of epidemic conditions. Method 1 is simple to implement but relies on locally appropriate mortality data, whilst method 2 can make use of the same survival distribution in a wide range of scenarios. The estimates from both methods are within the 95% confidence intervals of almost all actual measurements of HIV incidence in adults and young people, and the patterns of incidence over age are correctly captured.

CONCLUSIONS

It is possible to estimate incidence from cross-sectional prevalence data with sufficient accuracy to monitor the HIV epidemic. Although these methods will theoretically work in any context, we have able to test them only in southern and eastern Africa, where HIV epidemics are mature and generalised. The choice of method will depend on the local availability of HIV mortality data.

Using mathematical modelling to help explain the differential increase in HIV incidence in New South Wales, Victoria and Queensland: importance of other sexually transmissible infections

Background: Since 1999 there has been an increase in the number of HIV diagnoses in Australia, predominantly among men who have sex with men (MSM), but the magnitude of increase differs between states: ~7% rise in New South Wales, ~96% rise in Victoria, and ~68% rise in Queensland. Methods: Epidemiological, clinical, behavioural and biological data were collated into a mechanistic mathematical model to explore possible reasons for this increase in HIV notifications in MSM. The model was then used to make projections to 2015 under various scenarios. Results: The model suggests that trends in clinical and behavioural parameters, including increases in unprotected anal intercourse, cannot explain the magnitude of the observed rise in HIV notifications, without a substantial increase in a ‘transmission-increasing’ factor. We suggest that a highly plausible biological factor is an increase in the prevalence of other sexually transmissible infections (STI). It was found that New South Wales required an ~2-fold increase in other STI to match the data, Victoria needed an ~11-fold increase, and Queensland required an ~9-fold increase. This is consistent with observed trends in Australia for some STI in recent years. Future projections also indicate that the best way to control the current rise in HIV notifications is to reduce the prevalence of other STI and to promote condom use, testing for HIV, and initiation of early treatment in MSM diagnosed during primary infection. Conclusions: Our model can explain the recent rise in HIV notifications with an increase in the prevalence of other STI. This analysis highlights that further investigation into the causes and impact of other STI is warranted in Australia, particularly in Victoria.

Estimating 'net' HIV-related mortality and the importance of background mortality rates

OBJECTIVES

To estimate mortality directly attributable to HIV in HIV-infected adults in low and middle income countries and discuss appropriate methodology.

DESIGN

: Illustrative analysis of pooled data from six studies across sub-Saharan Africa and Thailand with data on individuals with known dates of seroconversion to HIV.

METHODS

Five of the studies also had data from HIV-negative subjects and one had verbal autopsies. Data for HIV-negative cohorts were weighted by the initial age and sex distribution of the seroconverters. Using the survival of the HIV-negative group to represent the background mortality, net survival from HIV was calculated for the seroconverters using competing risk methods. Mortality from all causes and 'net' mortality were modelled using piecewise exponential regression. Alternative approaches are explored in the dataset without information on mortality of uninfected individuals.

RESULTS

The overall effect of the net mortality adjustment was to increase survivorship proportionately by 2 to 5% at 6 years post-infection. The increase ranged from 2% at ages 15-24 to 22% in those 55 and over. Mortality rate ratios between sites were similar to corresponding ratios for all-cause mortality.

CONCLUSION

Differences between HIV mortality in different populations and age groups are not explained by differences in background mortality, although this does appear to contribute to the excess at older ages. In the absence of data from uninfected individuals in the same population, model life tables can be used to calculate background rates.

HIV-infected Rwandan women have a high frequency of long-term survival

OBJECTIVES

To evaluate rates of long-term survival in a prospective, longitudinal, closed HIV cohort in Africa between 1986 and 2006.

METHODS

A total of 548 HIV-infected Rwandan women were recruited from prenatal clinics in Kigali and followed at 3-6 month intervals to February 2006. Overall, 401 women (73%) were HIV positive at initial cross-sectional testing in 1986 (seroprevalent cohort) and 147 women (27%) were initially HIV negative but seroconverted during follow-up from 1986 to 1993 (seroincident cohort). Kaplan-Meier survival methods were used to calculate survival times censored in mid-2003.

RESULTS

In February 2006, 109 women (20%) remained alive in the cohort. Time to 50% non-genocide mortality was 11.9 years among seroincident women and 8.9 years among seroprevalent women. Smoothed mortality rates increased with duration of follow-up to a peak of 0.12 deaths per person-year at 9.5 years of follow-up but subsequently declined. After 15 years of follow-up (pre-HAART introduction), the survival probability was 36% for seroincident women and 26% for seroprevalent women. Most survivors had virological and immunological evidence of disease progression. The median CD4 cell count of survivors declined from 447 cells/mul in 1998 to 268 cells/mul in 2003. Among survivors, 57 women (52%) met treatment criteria and initiated antiretroviral treatment by 2006.

CONCLUSION

Although median survival times in this cohort were similar to those observed in high-income countries, the rates of long-term survival after 15 years of follow-up were higher than expected. A levelling off of mortality rates during the late stages of follow-up may explain this high rate of long-term survival.

The natural history of HIV-1 subtype E infection in young men in Thailand with up to 14 years of follow-up

OBJECTIVE

We evaluated the progression to AIDS and death among 228 men who seroconverted within a 6-month window when in the Royal Thai Army between 1991 and 1995.

DESIGN AND METHODS

Men (N = 228) who seroconverted to HIV at 21-23 years of age between 1991 and 1995 were evaluated up to 14 years after HIV seroconversion. The seroconverters were matched with men who were seronegative when they were discharged from the military. In 2005-2006, the vital status was determined through the national mortality database and survivors were contacted for follow-up clinical and immunological assessment. Death certificates, medical records and next of kin interviews were used to evaluate the causes of death.

RESULTS

As of March 2006, among 228 seroconverters, 56 (24.6%) were alive, 171 (75.0%) had died and one (0.4%) had undetermined status. Among 255 HIV-seronegative individuals at baseline, 15 (5.9%) had died. The median time from HIV seroconversion to death was 7.8 years. The median time to AIDS death was 8.4 years. The median times from seroconversion to clinical AIDS and a CD4 cell count less than 200 cells/mul were 7.2 years and 6.5 years, respectively. The median time from seroconversion to World Health Organization criteria for antiretroviral therapy was 6.3 years.

CONCLUSION

Our data indicate a more rapid progression to AIDS and death after HIV-1 infection among young Thai men than has been reported in similar aged men who were HAART-naive in western high income countries.

Time from HIV seroconversion to death: a collaborative analysis of eight studies in six low and middle-income countries before highly active antiretroviral therapy

OBJECTIVES

To estimate survival patterns after HIV infection in adults in low and middle-income countries.

DESIGN

An analysis of pooled data from eight different studies in six countries.

METHODS

HIV seroconverters were included from eight studies (three population-based, two occupational, and three clinic cohorts) if they were at least 15 years of age, and had no more than 4 years between the last HIV-negative and subsequent HIV-positive test. Four strata were defined: East African cohorts; South African miners cohort; Thai cohorts; Haitian clinic cohort. Kaplan-Meier functions were used to estimate survival patterns, and Weibull distributions were used to model and extend survival estimates. Analyses examined the effect of site, age, and sex on survival.

RESULTS

From 3823 eligible seroconverters, 1079 deaths were observed in 19 671 person-years of follow-up. Survival times varied by age and by study site. Adjusting to age 25-29 years at seroconversion, the median survival was longer in South African miners: 11.6 years [95% confidence interval (CI) 9.8-13.7] and East African cohorts: 11.1 years (95% CI 8.7-14.2) than in Haiti: 8.3 years (95% CI 3.2-21.4) and Thailand: 7.5 years (95% CI 5.4-10.4). Survival was similar for men and women, after adjustment for age at seroconversion and site.

CONCLUSION

Without antiretroviral therapy, overall survival after HIV infection in African cohorts was similar to survival in high-income countries, with a similar pattern of faster progression at older ages at seroconversion. Survival appears to be significantly worse in Thailand where other, unmeasured factors may affect progression.

Survival of HIV-infected treatment-naive individuals with documented dates of seroconversion in Rakai, Uganda

OBJECTIVE

To estimate the survival time from HIV infection to death.

METHODS

A community cohort in Rakai district, Uganda, identified 837 seroconverters followed annually between 1995 and 2003 until they died, were censored by outmigration or truncated on 31 December 2003 because antiretroviral treatment became available. HIV-1 subtype was determined by multiple hybridization assay for 396 seroconverters. The median interval from infection to death was estimated by Kaplan-Meier survival analyses and Weibull models. Hazard ratios (HR) and their 95% confidence intervals (CI) associated with survival were estimated using Cox proportional hazards modeling

RESULTS

There were 122 deaths over 2330 person-years (py), an average mortality of 5.2/100 py. The median survival time was 8.7 years (95% CI 8.1-9.3), and did not differ by sex, place of residence or time period of seroconversion. Survival time decreased significantly with older age at infection (P = 0.01). Survival was shorter with subtypes D, AD recombinant or multiple infections compared with subtype A (log rank P = 0.04), but this was of borderline significance after adjustment (adjusted HR 3.47, 95% CI 0.89-15.44, P = 0.07). Non-A subtypes constituted 84.6% of all identifiable infections and had a median survival time of 7.5 years (95% CI 6.4-8.5), whereas over 90% of those infected with subtype A were still alive 7 years post-infection.

CONCLUSION

The median survival time in Rakai was shorter than reported in other African populations, and we hypothesize that this may be a result of the predominance of non-A subtypes with faster disease progression in this population.

HIV-1 disease progression and mortality before the introduction of highly active antiretroviral therapy in rural Uganda

OBJECTIVE

To provide estimates of survival and progression to different HIV disease endpoints after HIV infection among adults in a rural Ugandan setting.

DESIGN

A prospective population-based cohort study.

METHODS

Eligible individuals at least 15 years of age with documented HIV seroconversion were recruited from a general population cohort in rural Uganda, along with a randomly selected proportion of HIV-prevalent and HIV-negative individuals. All participants were followed up every 3 months, and CD4 cell counts taken every 6 months in HIV-positive participants. Life tables and Kaplan-Meier functions were used to estimate survival patterns for all endpoints [death, time to World Health Organization (WHO) stage 2, 3, AIDS and CD4 cell count < 200 cells/mul]. Analysis of follow-up time was truncated when antiretroviral therapy (ART) became available in the area in January 2004.

RESULTS

We recruited 240 HIV incident cases, 108 prevalent cases and 257 HIV-negative controls. Crude mortality rates were 70.0 per 1000 person-years in HIV-positive, and 12.1 per 1000 person-years in HIV-negative individuals. The median time from seroconversion to death was 9.0 years (N = 240) and 6.2 years to a CD4 cell count less than 200 cells/mul or WHO stage 4 (N = 229). The median time from ART eligibility (CD4 cell count < 200 cells/mul, < 350 cells/mul and WHO stage 3, or WHO stage 4) to death was 34.7 months. Older age at seroconversion was a risk factor for faster progression to death and ART eligibility.

CONCLUSION

HIV progression in this African cohort is similar to that reported in industrialized countries before the widespread introduction of ART.

Survival of blood donors and their spouses with HIV-1 subtype E (CRF01 A_E) infection in northern Thailand, 1992-2007

OBJECTIVES

To evaluate the survival patterns among adults in Thailand 8-14 years after HIV-1 subtype E (CRF01 A_E) infection.

DESIGN

Follow-up for the current vital status of adults who were estimated to have had incident HIV-1 subtype E infection 8-14 years previously.

METHODS

Data on the survival of a population of HIV-1-infected male blood donors and their seropositive wives was obtained during March-April 2007. These subjects were identified from a subpopulation of 150 individuals whose seroconversion interval was estimated to be less than 2 years and who were enrolled in 1992-1997. National registration, vital records, and death certificates, as appropriate, were obtained and Kaplan-Meier survival curves were constructed for the entire population, for males and females, and for individuals above and equal to or below the median age at infection.

RESULTS

The vital status was obtained for 138 of 150 subjects (92%). The overall median survival was 8.2 [95% confidence interval (CI) 7.1-9.4] years. The median survival did not differ significantly between men and women or in those above or below the median age.

CONCLUSION

The median survival of 8.2 years in this population of young adults in Thailand was significantly less than that reported among persons of similar age in high-income countries or in eastern or southern Africa. The survival among individuals in Thailand infected with HIV-1 subtype E appears to be similar to that reported among individuals in Africa infected with HIV-1 subtype D.

The importance of militaries from developing countries in global infectious disease surveillance

Military forces from developing countries have become increasingly important as facilitators of their government's foreign policy, taking part in peacekeeping operations, military exercises and humanitarian relief missions. Deployment of these forces presents both challenges and opportunities for infectious disease surveillance and control. Troop movements may cause or extend epidemics by introducing novel agents to susceptible populations. Conversely, military units with disease surveillance and response capabilities can extend those capabilities to civilian populations not served by civilian public health programmes, such as those in remote or post-disaster settings. In Peru and Thailand, military health organizations in partnership with the military of the United States use their laboratory, epidemiological, communications and logistical resources to support civilian ministry of health efforts. As their role in international affairs expands, surveillance capabilities of militaries from developing countries should be enhanced, perhaps through partnerships with militaries from high-income countries. Military-to-military and military-to-civilian partnerships, with the support of national and international civilian health organizations, could also greatly strengthen global infectious disease surveillance, particularly in remote and post-disaster areas where military forces are present.

Predictors of disease progression in HIV infection: a review

During the extended clinically latent period associated with Human Immunodeficiency Virus (HIV) infection the virus itself is far from latent. This phase of infection generally comes to an end with the development of symptomatic illness. Understanding the factors affecting disease progression can aid treatment commencement and therapeutic monitoring decisions. An example of this is the clear utility of CD4+ T-cell count and HIV-RNA for disease stage and progression assessment. Elements of the immune response such as the diversity of HIV-specific cytotoxic lymphocyte responses and cell-surface CD38 expression correlate significantly with the control of viral replication. However, the relationship between soluble markers of immune activation and disease progression remains inconclusive. In patients on treatment, sustained virological rebound to >10,000 copies/mL is associated with poor clinical outcome. However, the same is not true of transient elevations of HIV RNA (blips). Another virological factor, drug resistance, is becoming a growing problem around the globe and monitoring must play a part in the surveillance and control of the epidemic worldwide. The links between chemokine receptor tropism and rate of disease progression remain uncertain and the clinical utility of monitoring viral strain is yet to be determined. The large number of confounding factors has made investigation of the roles of race and viral subtype difficult, and further research is needed to elucidate their significance. Host factors such as age, HLA and CYP polymorphisms and psychosocial factors remain important, though often unalterable, predictors of disease progression. Although gender and mode of transmission have a lesser role in disease progression, they may impact other markers such as viral load. Finally, readily measurable markers of disease such as total lymphocyte count, haemoglobin, body mass index and delayed type hypersensitivity may come into favour as ART becomes increasingly available in resource-limited parts of the world. The influence of these, and other factors, on the clinical progression of HIV infection are reviewed in detail, both preceding and following treatment initiation.

Survival from HIV-1 seroconversion in Southern Africa: a retrospective cohort study in nearly 2000 gold-miners over 10 years of follow-up

OBJECTIVE

To obtain robust estimates of survival with HIV in individuals with known dates of seroconversion in Africa in the pre-antiretroviral era.

DESIGN AND METHODS

Mortality rates were estimated in men from four South African gold mines in a retrospective cohort study with 10-year follow-up. HIV testing was carried out with counselling and consent, in random surveys in the early 1990s and in clinics. A total of 1950 HIV-positive men with seroconversion intervals < 3 years were compared with 6164 HIV-negative men with no subsequent evidence of HIV. Unique industry numbers were used to link medical records to demographic and occupational information. Follow-up after leaving the mine was conducted through employment offices across southern Africa, and using South African death registration data.

RESULTS

Follow-up was complete for 85% of those who seroconverted. Median survival was 10.5 years overall: 11.5 years for those aged 15-24 at seroconversion, 10.5 years for those aged 25-34, 9.5 years for those aged 35-44, and 6.3 years for those aged 45+ years. The relative mortality rate in comparison with HIV-uninfected miners increased quickly, reaching 13 for those HIV-infected for at least 9 years, and did not vary by age group. Excess mortality increased with age and duration of infection to > 10% per year. Adjusted to age 25-29 years at seroconversion, 5-year survival was 89% and 10-year 62%.

DISCUSSION

This study reports by far the largest cohort of individuals with known dates of seroconversion available in Africa. After adjusting for age, the survival pattern was similar to that seen in the West before antiretroviral therapy was available.

Progression to WHO criteria for antiretroviral therapy in a 7-year cohort of adult HIV-1 seroconverters in Abidjan, Côte d'Ivoire

OBJECTIVE

To estimate the probability of reaching the criteria for starting highly active antiretroviral therapy (HAART) in a prospective cohort of adult HIV-1 seroconverters in Abidjan, Côte d'Ivoire.

METHODS

We recruited participants from HIV-positive donors at the blood bank of Abidjan for whom the delay since the estimated date of seroconversion (midpoint between last negative and first positive HIV-1 test) was < 36 months. Participants were offered early trimethoprim-sulfamethoxazole (cotrimoxazole) prophylaxis, twice-yearly measurement of CD4 count and we made standardized records of morbidity. We used the Kaplan-Meier method to estimate the probability of reaching the criteria for starting HAART according to WHO 2006 guidelines.

FINDINGS

217 adults (77 women (35%)) were followed up during 668 person-years (PY). The most frequent diseases recorded were mild bacterial diseases (6.0 per 100 PY), malaria (3.6/100 PY), herpes zoster (3.4/100 PY), severe bacterial diseases (3.1/100 PY) and tuberculosis (2.1/100 PY). The probability of reaching the WHO 2006 criteria for HAART initiation was estimated at 0.09, 0.16, 0.24, 0.36 and 0.44 at 1, 2, 3, 4 and 5 years, respectively.

CONCLUSION

Our data underline the incidence of the early HIV morbidity in an Ivorian adult population and provide support for HIV testing to be made more readily available and for early follow-up of HIV-infected adults in West Africa.

Viral load and CD4 count dynamics after HIV-1 seroconversion in homosexual and bisexual men in Rio de Janeiro, Brazil

PURPOSE

Reliable predictors of HIV disease progression are scarce in developing countries, where most HIV infections occur. We describe early virologic and immunologic events among men who have sex with men in Rio de Janeiro, Brazil.

METHODS

Seroconverters from 2 high-risk cohorts were followed for up to 36 months with periodic laboratory evaluations, plasma viral load, and CD4 count assessments. Viral load and CD4 count mean trajectories were computed. For the modeled viral loads, mean and median values were 24,480 (4.36 log10) and 19,720 (4.29 log10) copies/mL (range 14,880-58,090), respectively. Median CD4 count was 373 cells/microL (range 260-508). Overall variation on viral loads ranged from 4.3 to 5.2 log10 copies/mL with a visible increase in the viral load starting at approximately 600 days (n = 12) after estimated time of seroconversion. The initial period of HIV infection was characterized by an increase in CD4 count (n = 29) followed by a steep decline starting at approximately 200 days (508 cells, 95% CI: 425 to 569). A gradual decrease was observed in the median CD4 count thereafter, reaching 281 (95% CI: 100 to 466) at 1000 days after the estimated date of seroconversion.

CONCLUSIONS

Although viral load dynamics resembled those observed in developed countries, CD4 counts seem to decline at a faster rate than in the Multicenter AIDS Cohort Study (MACS) cohort. Clinical and survival data are needed to assess the impact of interventions, such as antiretroviral therapy, on the clinical course of HIV infection in Brazil.

The potential impact of enhanced diagnostic techniques for tuberculosis driven by HIV: a mathematical model

OBJECTIVE

To explore the potential impact of enhanced tuberculosis (TB) diagnostic techniques as a TB control strategy in an adult population with high HIV prevalence.

DESIGN

A compartmental difference-equation model of TB/HIV was developed using parameter estimates from the literature.

METHODS

The impact of five TB control interventions (rapid molecular testing, mycobacterial culture, community-wide and HIV-targeted active case finding, and highly active antiretroviral therapy) on TB incidence, prevalence, and mortality was modeled in a steady-state population with an HIV prevalence of 17% and annual TB incidence of 409 per 100 000. Sensitivity analyses assessed the influence of each model parameter on the interventions' mortality impact.

RESULTS

Enhanced diagnostic techniques (rapid molecular testing or culture) are each projected to reduce TB prevalence and mortality by 20% or more, an impact similar to that of active case-finding in 33% of the general community and greater than the effect achievable by case-finding or antiretroviral treatment efforts in HIV-positive patients alone. The projected impact of enhanced diagnostics on TB incidence (< 10% reduction) is smaller. The impact of TB diagnostics is sensitive to the quality of existing diagnostic standards and the level of access to diagnostic services, but is robust across a wide range of population parameters including HIV and TB incidence.

CONCLUSIONS

Enhanced TB diagnostic techniques may have substantial impact on TB morbidity and mortality in HIV-endemic regions. As TB rates continue to increase in these areas, enhanced diagnostic techniques merit further consideration as TB control strategies.

HIV-1 subtype E progression among northern Thai couples: traditional and non-traditional predictors of survival

BACKGROUND

In the continuing effort to introduce antiretroviral therapy in resource-limited settings, there is a need to understand differences between natural history of HIV in different populations and to identify feasible clinical measures predictive of survival.

METHODS

We examined predictors of survival among 836 heterosexuals who were infected with HIV subtype CRF01_AE in Thailand.

RESULTS

From 1993 to 1999, 269 (49.4%) men and 65 (25.7%) women died. The median time from the estimated seroconversion to death was 7.8 years (95% confidence interval 7.0-9.1). Men and women with enrolment CD4 counts <200 cells/microl had about 2 and 11 times greater risk of death than those with CD4 counts of 200-500 and >500, respectively. Measurements available in resource-limited settings, including total lymphocyte count (TLC), anaemia, and low body mass index (BMI), also predicted survival. Men with two or more of these predictors had a median survival of 0.8 (0.5-1.8) years, compared with 2.7 (1.9-3.3) years for one predictor and 4.9 (4.1-5.2) years for no predictors.

CONCLUSIONS

The time from HIV infection to death appears shorter among this Thai population than among antiretroviral naive Western populations. CD4 count and viral load (VL) were strong, independent predictors of survival. When CD4 count and VL are unavailable, individuals at high risk for shortened HIV survival may be identified by a combination of low TLC, anaemia, and low BMI. This combination of accessible clinical measures of the disease stage may be useful for medical management in resource-limited settings.

HIV/AIDS in Asia

HIV (ie, HIV-1) epidemics in Asia show great diversity, both in severity and timing. But epidemics in Asia are far from over and several countries including China, Indonesia, and Vietnam have growing epidemics. Several factors affect the rate and magnitude of growth of HIV prevalence, but two of the most important are the size of the sex worker population and the frequency with which commercial sex occurs. In view of the present state of knowledge, even countries with low prevalence of infection might still have epidemics affecting a small percentage of the population. Once HIV infection has become established, growing needs for care and treatment are unavoidable and even the so-called prevention-successful countries of Thailand and Cambodia are seeing burgeoning care needs. The manifestations of HIV disease in the region are discussed with the aim of identifying key issues in medical management and care of HIV/AIDS. In particular, issues relevant to developing appropriate highly active antiretroviral treatment programmes in the region are discussed. Although access to antiretroviral therapy is increasing globally, making it work effectively while simultaneously expanding prevention programmes to stem the flow of new infections remains a real challenge in Asia. Genuine political interest and commitment are essential foundations for success, demanding advocacy at all levels to drive policy, mobilise sufficient resources, and take effective action.

Lymphocyte homeostasis in HIV-infected northern Thais

Cross-sectional laboratory data were used to model the patterns of total lymphocyte count and lymphocyte subpopulation counts among persons with chronic HIV-1 subtype E (CRF01_AE) infection during the 6.5 years preceding death. The data cover 331 HIV-infected decedents from a heterosexual HIV transmission study of 590 northern Thai couples enrolled in 1992-1998. From blood collected at enrollment, the lymphocyte phenotypes (CD3, CD8, CD4, natural killer, and B cells) were stained using two-color monoclonal antibody combinations and quantified by flow cytometry. Piecewise linear splines modeled the associations between lymphocyte levels and time before death. Mean CD3, CD8, and B cell levels showed no temporal associations from 6.5 to 2 years before death, but each declined significantly during the 2 years before death. CD3 levels declined 31.0% [95% confidence interval (-40.3%, -19.8%)] and CD8 levels declined 24.6% (-35.4%, -13.5%) annually in the 2 years prior to death. In contrast, CD4 and NK cell levels declined little from 6.5 to 4.5 years before death but declined significantly over the 4.5 years prior to death. CD4 levels declined 22.1% (-29.2%, -12.0%) annually from 4.5 to 2 years prior to death and 63.7% (-72.3%, -53.6%) annually over the remaining 2 years. Similar lymphocyte patterns have been reported in U. S. and European populations with HIV-1 subtype B infection.