Number Of HIV-infected Individuals Research Articles

Stability and optimal control of a delayed HIV/AIDS-PrEP model

<p style='text-indent:20px;'>In this paper, we propose a time-delayed HIV/AIDS-PrEP model which takes into account the delay on pre-exposure prophylaxis (PrEP) distribution and adherence by uninfected persons that are in high risk of HIV infection, and analyze the impact of this delay on the number of individuals with HIV infection. We prove the existence and stability of two equilibrium points, for any positive time delay. After, an optimal control problem with state and control delays is proposed and analyzed, where the aim is to find the optimal strategy for PrEP implementation that minimizes the number of individuals with HIV infection, with minimal costs. Different scenarios are studied, for which the solutions derived from the Minimum Principle for Multiple Delayed Optimal Control Problems change depending on the values of the time delays and the weights constants associated with the number of HIV infected individuals and PrEP. We observe that changes on the weights constants can lead to a passage from <i>bang-singular-bang</i> to <i>bang-bang</i> extremal controls.</p>

Model-free based control of a HIV/AIDS prevention model.

Controlling an epidemiological model is often performed using optimal control theory techniques for which the solution depends on the equations of the controlled system, objective functional and possible state and/or control constraints. In this paper, we propose a model-free control approach based on an algorithm that operates in 'real-time' and drives the state solution according to a direct feedback on the state solution that is aimed to be minimized, and without knowing explicitly the equations of the controlled system. We consider a concrete epidemic problem of minimizing the number of HIV infected individuals, through the preventive measure pre-exposure prophylaxis (PrEP) given to susceptible individuals. The solutions must satisfy control and mixed state-control constraints that represent the limitations on PrEP implementation. Our model-free based control algorithm allows to close the loop between the number of infected individuals with HIV and the supply of PrEP medication 'in real time', in such a manner that the number of infected individuals is asymptotically reduced and the number of individuals under PrEP medication remains below a fixed constant value. We prove the efficiency of our approach and compare the model-free control solutions with the ones obtained using a classical optimal control approach via Pontryagin maximum principle. The performed numerical simulations allow us to conclude that the model-free based control strategy highlights new and interesting performances compared with the classical optimal control approach.

Temporal trends in sexual behaviours and their impacts on HIV incidence among South African women: 2002–2016

ABSTRACT South Africa has the highest number of HIV infected individuals in the world. The primary objective of the current study was to describe temporal changes in HIV incidence rates using the data from 9,948 women who enrolled in one of the six HIV prevention trials conducted in KwaZulu-Natal, South Africa. Characteristics of the study population were presented and compared across the four study periods: 2002–2004, 2005–2008, 2009–2011 and 2012–2016. HIV infection rates increased from 6.2 to 9.3 per 100 person-year over the 15 years. These rates were as high as 14 per 100 person-year among women younger than 20 years age. Being single/not cohabiting, using injectable contraceptives, having less than two children, and diagnosed with STI(s) were associated with increased risk of HIV infection. These four factors were associated with 71%, 75%, 80% and 88% of the HIV seroconversions in four study periods. As the research continues to find ways of controlling the spread of the infections, quantifying the temporal trends in risk factors and their population-level impacts on HIV infection may have significant implications. This information may assist in developing effective counselling and education programs by targeting the sexually active single women and delivering more realistic messages.

Strategies of optimal control for HIV spreads prevention with health campaign

In the present paper, we discuss an HIV (Human Immunodeficiency Virus) transmission model with health information campaign about HIV control policies. The reason behind the conception of this model is the idea to divide the human population that gains awareness of HIV, due to this campaign. We assume that HIV will not infect people who are aware about the dangers of HIV. We analyze the existence and local stability of the equilibrium points. We found that the disease-free equilibrium point will be locally asymptotically stable (LAS) if the basic reproduction number (R0) is less than one, and unstable otherwise. A forward bifurcation of the system is shown numerically, depending on the intervention parameters. Some numerical simulations for the autonomous system are given to see the evolution of the system, with respect to some scenarios that might appear in the field. To accommodate the limitation of budget issue for implementation in the field, the model is reconstructed as an optimal control problem with two control variables. Numerical simulations for optimal control problems are presented for five different scenarios. Numerical simulation results suggest that controlling strategies by providing health campaigns is better, if they precede an endemic prevention strategy than endemic reduction, since the cost needed for endemic reduction is five times higher, compared with the endemic prevention. Optimal intervention should also note the value of R0. Larger control levels are needed when R0 > 1 if compared with when R0 < 1. The results of numerical simulation also show that the lower the cost of the health campaign, the more health campaigns can be provided. Based on the numerical simulation calculations, the optimal intervention of health campaign can raise public awareness about HIV, in order to reduce the number of HIV-infected individuals.

A portrait of risk behavior towards HIV infection among Brazilian Army conscripts by geographic regions, 2016.

Knowledge about risky sexual behavior among young people has been widely acknowledged as a key tool to controlling the spread of HIV. This article aimed at presenting the risk behavior of Brazilian Army conscripts toward HIV infection according to the country's geographic regions. . We collected data from 37,282 conscripts, aged 17 to 22, during enlistment in the Brazilian Army in 2016. The prevalence of HIV infection, both self-reported and measured through laboratory results, and risk behavior factors were estimated by region. 75% of the sample of conscripts reported to have already started sexual activity, and the average age of their sexual initiation was 15. Condom use varied according to the type of sexual relationship, being lower among steady partners and greater among less stable relationships. HIV prevalence assessed by laboratory tests was 0.12% across the country and the highest prevalence was observed in the North region (0.24%). Alcohol and illicit drug usage was higher in the South region. The study allowed the observation of risk behavior monitoring for HIV infection among young Brazilians. Lower condom usage among steady partners may be contributing to an increase in the number of HIV-infected individuals. Results suggest the need to intensify prevention campaigns to disseminate safe sex practices among young people, in addition to the expansion of testing offer to this population.

Spontaneous HIV controllers

HIV A small number of HIV-infected individuals (<1%) can spontaneously control HIV in the absence of antiretroviral therapy. Because CD4+ and CD8+ T cell responses are thought to contribute to protection, HIV-responsive T cell receptors (TCRs) from these individuals are of considerable interest. Galperin et al. examined how three class II–restricted TCRs observed in spontaneous controllers are capable of binding a Gag peptide in the context of multiple HLA-DR molecules (HLA, human leukocyte antigen). The authors solved the structures of several TCR–peptide–HLA-DR complexes. The findings suggest that the ability of these TCRs to recognize the Gag peptide in the context of multiple HLA-DR allomorphs is shaped by extensive contacts between the TCRs and the peptide itself. Sci. Immunol. 3 , eaat0687 (2018).

Mucocutaneous infections in HIV positive patients attending a tertiary care institution: a descriptive study

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;AIDS is characterized by the waning of body’s immunity leaving the victim to the multitude of life threatening opportunistic infections, neurological disorders or malignancies. Dermatologic manifestations occur in more than 90% of patients with HIV infection most often due to infections. The awareness of the varied patterns of these skin lesions would help in early diagnosis and management of these in HIV infection, which in turn reduce the morbidity and improve quality of life.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Observational study from 1&lt;sup&gt;st&lt;/sup&gt; April 2012 to 31&lt;sup&gt;st&lt;/sup&gt; March 2013 in a tertiary care institution of North Kerala. HIV positive patients attending sexually transmitted infection clinic of Dermato venereology department, anti-retroviral treatment clinic (ART clinic) and infectious diseases ward of Department of Medicine of a tertiary care centre were examined after consent for mucocutaneous infections. &lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The study population comprised of 206 HIV infected patients with mucocutaneous infections. The male to female ratio was 2.07:1. Most of the affected belong to 30-50 years age group. Majority were manual laborers(49.3%) and in stage3 HIV disease. 107 patients had CD4 Count below 350 at the time of study(51.9%) whereas 40 cases (19.4%) had CD4Count above 500.&lt;strong&gt; &lt;/strong&gt;Most common mucocutaneous infection was oral candidiasis (51%), followed by onychomycosis (16.5%). Out of 29 patients with dermatophytosis majority had tinea cruris (18 patients). Bacterial was second commonest infection. Only 3 patients had tuberculoid leprosy, one with type 1 reaction.&lt;strong&gt; &lt;/strong&gt;Common viral infection was herpes zoster followed by herpes genitalis and conyloma accuminata. 11 patients had verruca vulgaris, one with extensive lesions.&lt;strong&gt; &lt;/strong&gt;Out of 206 patients 28 had sexually transmitted infections (STIs) other than HIV, herpes genitalis being the commonest. Syphilis observed in 4 patients (1.9%). 162 patients (78.6%) were on HAART. The response to treatment was better in patients with CD4 Count above 500cells/mm&lt;sup&gt;3&lt;/sup&gt;. &lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt;Oral candidiasis, onychomycosis, pyoderma and ulcerative STIs were noted in significant number of HIV infected individuals. These were more common in those with CD4Count below 300 cells/ mm&lt;sup&gt;3&lt;/sup&gt;. &lt;sup&gt;.&lt;/sup&gt;Those patients with CD4 Count above 500 cells/ mm&lt;sup&gt;3&lt;/sup&gt; responded well to treatment. &lt;/p&gt;

Ethnicity predicts viral rebound after travel to the tropics in HIV-infected travelers to the tropics in the Swiss HIV Cohort Study.

The number of HIV-infected individuals from developed countries travelling to tropical and subtropical areas has increased as a result of the clinical and survival benefits of combination antiretroviral therapy. The aim of our study was to describe the traveler population in the SHCS and to determine the frequency of viral rebound in virologically suppressed individuals after a travel episode to the tropics compared to non-travelers. Swiss HIV Cohort Study participants with at least one follow-up visit between 1 January 1989 and 28 February 2015 were eligible for inclusion in the study. The primary outcome was the occurrence of viral rebound (viral load > 200 HIV-1 RNA copies/mL) after a travel episode compared with a nontravel episode in previously suppressed individuals (≤ 200 copies/mL). All virologically suppressed patients contributed multiple travel or nontravel episodes to the analysis. Logistic regression was performed including factors associated with viral rebound. We included 16 635 patients in the study, of whom 6084 (36.5%) had ever travelled to the tropics. Travel frequency increased over time, with travellers showing better HIV parameters than nontravellers [less advanced Centers for Disease Control and Prevention (CDC) stage and higher CD4 count nadir]. Viral rebound was seen in 477 (3.9%) of 12 265 travel episodes and in 5121 (4.5%) of 114 884 nontravel episodes [unadjusted odds ratio (OR) 0.87; 95% confidence interval (CI) 0.78-0.97]. Among these 477 post-travel viral rebounds, 115 had a resistance test performed and 51 (44%) of these showed new resistance mutations. Compared with European and North American patients, the odds for viral rebound were significantly lower in Southeast Asian (OR 0.67; 95% CI 0.51-0.88) and higher in sub-Saharan African (SSA) patients (OR 1.41; 95% CI 1.22-1.62). Travel further increased the odds of viral rebound in SSA patients (OR 2.00; 95% CI 1.53-2.61). Region of origin is the main risk factor for viral rebound rather than travel per se. Pre-travel adherence counselling should focus on patients of SSA origin.

ACOUIRED IMMUNE DEFICIENCY SYNDROME

HIV/AIDS is one of the most important problems of world health care. Number of HIV infected individuals in the world are about 40 millions and continue rising. Fight against HIV/AIDS is one of United Nations’ «Millenium Goals». Efforts of many research institutions and unprecedented financial resources are mobilized for counteraction of the disease. Despite intensive investigations there are no radical treatment or effective preventive vaccine, which is able to protect vulnerable populations from HIV infection. The key steps of HIV/AIDS investigations, development of drugs and strategies of prevention and treatment of the disease, and also perspectives of epidemic control are reviewed.

Identifying Factors Associated with Low-Adherence and Subsequent HIV Seroconversions Among South African Women Enrolled in a Biomedical Intervention Trial.

Sub-Saharan Africa has the highest number of HIV infected individuals in the world. Developing and implementing effective biomedical interventions still remains urgent. Poor adherence has been commonly identified as one of the major barriers for the success of HIV prevention trials. A better understanding of how to improve adherence remains a research priority. In this analysis, younger age (<35years), number of children≤2, being single/not cohabiting and having a new partner during the study follow up were all significantly associated with poor adherence and subsequent HIV seroconversions. At population level, these three factors collectively associated with 56% of the low level adherence and 75% of the HIV seroconversions. Results highlighted the importance of effective adherence and comprehensive contraceptive counselling of women who enrol in HIV prevention trials. Culturally and socially appropriate methods are needed to achieve and maintain optimum adherence levels in future HIV prevention research.

High rate of missed HIV infections in individuals with indeterminate or negative HIV western blots based on current HIV testing algorithm in China.

It remains unclear if China's current HIV antibody testing algorithm misses a substantial number of HIV infected individuals. Of 196 specimens with indeterminate or negative results on HIV western blot (WB) retrospectively examined by HIV-1 nucleic acid test (NAT), 67.57% (75/111) of indeterminate WB samples, and 16.47% (14/85) of negative WB samples were identified as NAT positive. HIV-1 loads in negative WB samples were significantly higher than those in indeterminate WB samples. Notably, 86.67% (13/15) of samples with negative WB and double positive immunoassay results were NAT positive. The rate of HIV-1 infections missed by China's current HIV testing algorithm is unacceptably high. Thus, China should consider using NAT or integrating fourth generation ELISA into current only antibodies-based HIV confirmation. J. Med. Virol. 88:1462-1466, 2016. © 2016 Wiley Periodicals, Inc.

Trends and Characteristics of HIV Infection among Suspected Tuberculosis Cases in Public Health Centers in Korea: 2001–2013

ObjectivesThe Republic of Korea reports approximately 35,000 new tuberculosis (TB) patients each year, and the number of HIV-infected individuals is steadily increasing. Public health centers (PHCs) conduct TB diagnosis and treatment for risk groups in communities. This study aimed to identify possible trends and characteristics of HIV infection among suspected TB cases in PHCs. MethodsStudy subjects were suspected TB cases in PHCs who agreed to be tested for HIV from 2001 to 2013. Trends in HIV seroprevalence were assessed through a series of annual cross-sectional analyses. We analyzed suspected TB cases, and HIV-infected individuals among suspected TB cases, by gender, age, nationality, and region. ResultsThe number of suspected tuberculosis cases who took an HIV test in PHCs was approximately 6,000 each year from 2001 to 2013. Among the suspected TB cases who took an HIV test, the number of those aged 20–39 is gradually decreasing, while the number of those aged 50–69 is increasing. During this period, 32 HIV-infected individuals were identified; the majority were men (94%), aged 30–49 (68%), Korean (94%), and residents in a metropolitan area (53%). HIV seroprevalence decreased from 8.2 per 10,000 persons in 2001 to 1.9 per 10,000 persons in 2013. ConclusionThis study has identified trends and characteristics of HIV infection among suspected tuberculosis cases in PHCs. This national data provides a basis for public health policy for HIV and tuberculosis infections.

Developing Combined HIV Vaccine Strategies for a Functional Cure.

Increasing numbers of HIV-infected individuals have access to potent antiretroviral drugs that control viral replication and decrease the risk of transmission. However, there is no cure for HIV and new strategies have to be developed to reach an eradication of the virus or a natural control of viral replication in the absence of drugs (functional cure). Therapeutic vaccines against HIV have been evaluated in many trials over the last 20 years and important knowledge has been gained from these trials. However, the major obstacle to HIV eradication is the persistence of latent proviral reservoirs. Different molecules are currently tested in ART-treated subjects to reactivate these latent reservoirs. Such anti-latency agents should be combined with a vaccination regimen in order to control or eradicate reactivated latently-infected cells. New in vitro assays should also be developed to assess the success of tested therapeutic vaccines by measuring the immune-mediated killing of replication-competent HIV reservoir cells. This review provides an overview of the current strategies to combine HIV vaccines with anti-latency agents that could act as adjuvant on the vaccine-induced immune response as well as new tools to assess the efficacy of these approaches.

Disparities in the Burden of HIV/AIDS in Canada

BackgroundWe aimed to characterize changes in patterns of new HIV diagnoses, HIV-related mortality, and HAART use in Canada from 1995 to 2008.MethodsData on new HIV diagnoses were obtained from Health Canada, HIV-related mortality statistics were obtained from Statistics Canada, and information on the number of people on HAART was obtained from the single antiretroviral distribution site in British Columbia (BC), and the Intercontinental Marketing Services Health for Ontario and Quebec. Trends of new HIV-positive tests were assessed using Spearman rank correlations and the association between the number of individuals on HAART and new HIV diagnoses were estimated using generalized estimating equations (GEE).ResultsA total of 34,502 new HIV diagnoses were observed. Rates of death in BC are higher than those in Ontario and Quebec with the rate being 2.03 versus 1.06 and 1.21 per 100,000 population, respectively. The number of HIV infected individuals on HAART increased from 5,091 in 1996 to 20,481 in 2008 in the three provinces (4 fold increase). BC was the only province with a statistically significant decrease (trend test p<0.0001) in the rate of new HIV diagnoses from 18.05 to 7.94 new diagnoses per 100,000 population. Our analysis showed that for each 10% increment in HAART coverage the rate of new HIV diagnoses decreased by 8% (95% CI: 2.4%, 13.3%)InterpretationExcept for British Columbia, the number of new HIV diagnoses per year has remained relatively stable across Canada over the study period. The decline in the rate of new HIV diagnoses per year may be in part attributed to the greater expansion of HAART coverage in this province.

Low levels of anti-MPER antibodies are detectable in viremic HIV infected

Background Antibodies against the CD4 binding site (CD4bs) in gp120 and the membrane proximal extracellular region (MPER) of gp41 are associated with broadly neutralization capacity. While the former have been identified in a large number of HIV infected individuals, the latter show a much lower prevalence. Methods 31 HIV-infected individuals with detectable viremia were selected for the study. Two samples separated by at least one year were analyzed for each individual. The presence of anti-CD4bs was screened using a competitive flow cytometric assay with a CD4 IgG fusion protein. The presence of anti-MPER antibodies was screened using a sensitive flow cytometric assay that measures antibody binding to different cell lines stably expressing two different truncated forms of gp41. These molecules properly expose the MPER epitope, as assessed by staining with control antibodies 4E10 and 2F5. Results Detectable levels of both anti-CD4bs antibodies and antiMPER antibodies were observed in plasma samples from all groups. Of note, most samples showed recognition of MPER with a strong correlation between the recognition of the two different forms of truncated gp41 used (r=0.65, p<0.0001), suggesting that the assay was robust enough for the detection of these antibodies. However, no correlations were found between the level of anti-MPER antibodies, the neutralizing capacity of plasma samples, the viral load and the CD4 T-cell counts. Conclusion Anti-MPER antibodies can be detected in viremic chronic HIV infected individuals. The level of these antibodies does not appear to correlate with control of viremia or clinical progression. These data may suggest that anti-MPER antibodies are elicited in the course of HIV infection, but they do not reach the necessary threshold to be easily detectable or to impact infection.

Antiretroviral therapy (ART) adherence and correlates to non-adherence among people on ART in Estonia

There is limited data on antiretroviral therapy (ART) adherence among patients in Eastern Europe, despite the high incidence of HIV infection and the growing number of HIV-infected individuals who are being prescribed ART. We conducted a study to measure rates of adherence to ART and factors associated with non-adherence among patients receiving care at an outpatient HIV clinic in Estonia.

HIV and Reproduction: Fertility, Contraception, and Preconception Issues and Interventions

HIV and Reproduction: Fertility, Contraception, and Preconception Issues and Interventions

Gender, Race, and Geography: Do They Matter in Primary Human Immunodeficiency Virus Infection?

weeks, and by week 104 of follow-up, women had higher viral loads than men. Their data also suggest that women report fewer symptoms associated with the acute retroviral syndrome, which may delay or complicate early diagnosis in this population. These biologic differences between races and genders remain unexplained; however, there is little indication that these findings have major clinical significance. Nevertheless, a better understanding of the biologic factors leading to these differences may give insight into HIV pathogenesis. Although the lessons to be learned may be important, the likelihood is low that these will lead to interventions that will change disease course in the near future. The data of Meditz et al [4] also suggest that more immediate challenges lay at hand. The continued evidence of disparities in engagement in care and treatment based on race, gender, and geography is troubling, but not unexpected. In this era of ‘‘seek, test, and treat,’’ understanding these barriers to therapy is critically important, as appropriate interventions could have a rapid effect on disease course for significant numbers of HIV-infected individuals. This study focuses on individuals who receive appropriate HIV testing and are diagnosed in the early stages of infection, clearly a minority population among those living with HIV. Although the seek and test portions of the formula were performed optimally, the treat component proved not to be so easy. Women, nonwhites, and those living in the Southern United States were significantly less likely to start antiretroviral therapy and were

Health Promotion and Human Right Protection: Finding a Balance for HIV Testing Policies in U.S. State Prisons

In 2008, approximately 1.5 million people were reported to be incarcerated in a prison in the United States (Maruschak, 2009). Previous research has shown that many incarcerated individuals engage in high-risk sexual behaviors and/or have a history of substance abuse (Centers for Disease Control and Prevention [CDC], n.d., para. 2), thereby putting them in a high-risk group for contracting HIV infection. As one would expect, this high-risk behavior has translated into startling statistics. According to the most recent U.S. Bureau of Justice report, the number of HIV-infected individuals living in the United States who are incarcerated is approximately 2.5 times higher than that of the general population (Maruschak, 2009). What is even more alarming is the fact that many of the infected individuals are unaware of their HIV status at the time of incarceration (Desai, Latta, Spaulding, Rich, & Flanigan, 2002). In addition to the high-risk behaviors engaged in by many of those who enter prison before their incarceration, once an individual is established within the prison setting, high-risk behaviors often continue. Many studies have examined the incidence of sexual activity in prisons; however, the results have been far from conclusive. Saum, Surratt, Inciardi, and Bennett (1995) reported a rate of 2%, whereas an earlier survey that was conducted when HIV was a newly emerging and unknown infection estimated a much higher rate of 65% (Wooden & Parker, 1982).

Learning and doing: operational research and access to HIV treatment in Africa

Learning and doing: operational research and access to HIV treatment in Africa