Acute HIV revisited: new opportunities for treatment and prevention

Pooling strategies to reduce the cost of HIV-1 RNA load monitoring in a resource-limited setting

BACKGROUND

Quantitative human immunodeficiency virus (HIV) RNA load testing surpasses CD4 cell count and clinical monitoring in detecting antiretroviral therapy (ART) failure; however, its cost can be prohibitive. Recently, the use of pooling strategies with a clinically appropriate viral load threshold was shown to be accurate and efficient for monitoring when the prevalence of virologic failure is low.

METHODS

We used laboratory request form information to identify specimens with a low pretest probability of virologic failure. Patients aged ≥15 years who were receiving first-line ART had individual viral load results available were eligible. Blood plasma, dried blood spots, and dried plasma spots were evaluated. Two pooling strategies were compared: minipools of 5 samples and a 10 ×10 matrix platform (liquid plasma specimens only). A deconvolution algorithm was used to identify specimens(s) with detectable viral loads.

RESULTS

The virologic failure rate in the study sample was <10%. Specimens included were liquid plasma specimens tested in minipools(n = 400), of which 300 were available for testing by matrix, and specimens tested with minipools only: dried blood spots (n = 100) and dried plasma spots (n = 185). Pooling methods resulted in 30.5%-60% fewer HIV RNA tests required to screen the study sample. For plasma pooling, the matrix strategy had the better efficiency, but minipools of 5 dried blood spots had the best efficiency overall and were accurate at a >95% negative predictive value with minimal technical requirements.

CONCLUSIONS

In resource-constrained settings, a combination of preselection of patients with low pretest probability of virologic failure and pooled testing can reduce the cost of virologic monitoring without compromising accuracy.

Screening for acute HIV infection in South Africa: finding acute and chronic disease

BACKGROUND

The yield of screening for acute HIV infection among general medical patients in resource-scarce settings remains unclear. Our objective was to evaluate the strategy of using pooled HIV plasma RNA to diagnose acute HIV infection in patients with negative or discordant rapid HIV antibody tests in Durban, South Africa.

METHODS

We prospectively enrolled patients with negative or discordant rapid HIV antibody tests from a routine HIV screening programme in an out-patient department in Durban with an HIV prevalence of 48%. Study participants underwent venipuncture for pooled qualitative HIV RNA, and, if this was positive, quantitative RNA, enzyme immunoassay and Western blot (WB). Patients with negative or indeterminate WB and positive quantitative HIV RNA were considered acutely infected. Those with chronic infection (positive RNA and WB) despite negative or discordant rapid HIV tests were considered to have had false negative rapid antibody tests.

RESULTS

Nine hundred and ninety-four participants were enrolled with either negative (n=976) or discordant (n=18) rapid test results. Eleven [1.1%; 95% confidence interval (CI) 0.6-2.0%] had acute HIV infection, and an additional 20 (2.0%; 95% CI 1.3-3.1%) had chronic HIV infection (false negative rapid test).

CONCLUSIONS

One per cent of out-patients with negative or discordant rapid HIV tests in Durban, South Africa had acute HIV infection readily detectable through pooled serum HIV RNA screening. Pooled RNA testing also identified an additional 2% of patients with chronic HIV infection. HIV RNA screening has the potential to identify both acute and chronic HIV infections that are otherwise missed by standard HIV testing algorithms.

[37-year old patient with fever, diarrhea and lymphadenopathy]

A 37-year-old homosexual man was admitted because of oropharyngeal pain, fever, diarrhea, loss of weight and lymphadenopathy since one week. Acute retroviral syndrome (ARS) in primary HIV type 1 infection was diagnosed, associated with Giardia lamblia infection. Antiinfective and combined antiretroviral treatment was established, and the general condition of the patient rapidly improved. The presented report demonstrates that in case of acute HIV-infection with diarrhea other infections should be considered, particularly with regard to enteropathogens like Giardia lamblia.

Role of acute and early HIV infection in the sexual transmission of HIV

PURPOSE OF REVIEW

Acute HIV infection (AHI), the earliest period after HIV acquisition, is only a few weeks in duration. In this brief period, the concentration of HIV in blood and genital secretions is extremely high, increasing the probability of HIV transmission. Although a substantial role of AHI in the sexual transmission of HIV is biologically plausible, the significance of AHI in the epidemiological spread of HIV remains uncertain.

RECENT FINDINGS

AHI is diagnosed by detecting viral RNA or antigen in the blood of persons who are HIV seronegative. Depending on the setting, persons with AHI represent between 1 and 10% of persons with newly diagnosed HIV infection. The high concentration of virus during AHI leads to increased infectiousness, possibly as much as 26 times greater than during chronic infection. In mathematical models, the estimated proportion of transmission attributed to AHI has varied considerably, depending on model structure, model parameters, and the population. Key determinants include the stage of the HIV epidemic and the sexual risk profile of the population.

SUMMARY

Despite its brief duration, AHI plays a disproportionate role in the sexual transmission of HIV infection. Detection of persons with AHI may provide an important opportunity for transmission prevention.

PCR-based pooling of dried blood spots for detection of malaria parasites: optimization and application to a cohort of Ugandan children

Sensitive, high-throughput methods to detect malaria parasites in low-transmission settings are needed. PCR-based pooling strategies may offer a solution. We first used laboratory-prepared samples to compare 2 DNA extraction and 4 PCR detection methods across a range of pool sizes and parasite densities. Pooled Chelex extraction of DNA, followed by nested PCR of cytochrome b, was the optimal strategy, allowing reliable detection of a single low-parasitemic sample (100 parasites/μl) in pool sizes up to 50. This PCR-based pooling strategy was then compared with microscopy using 891 dried blood spots from a cohort of 77 Ugandan children followed for 2 years in an urban setting of low endemicity. Among 419 febrile episodes, 35 cases of malaria were detected using the PCR-based pooling strategy and 40 cases using microscopy. All five cases of malaria not detected by PCR were from samples stored for >2 years with parasitemia of <6,000/μl, highlighting the issue of possible DNA degradation with long-term storage of samples. Among 472 samples collected from asymptomatic children as part of routine surveillance, 15 (3.2%) were positive by PCR-based pooling compared to 4 (0.8%) by microscopy (P = 0.01). Thus, this PCR-based pooling strategy for detection of malaria parasites using dried blood spots offers a sensitive and efficient approach for malaria surveillance in low-transmission settings, enabling improved detection of asymptomatic submicroscopic infections and dramatic savings in labor and costs.

[AIDS Study Group/Spanish AIDS Plan consensus document on antiretroviral therapy in adults with human immunodeficiency virus infection (updated January 2010)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy recommendations for adult patients with human immunodeficiency virus infection.

METHODS

To formulate these recommendations a panel made up of members of the Grupo de Estudio de Sida (Gesida, AIDS Study Group) and the Plan Nacional sobre el Sida (PNS, Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of human immunodeficiency virus (HIV) infection, the efficacy and safety of clinical trials, and cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings. Three levels of evidence were defined according to the data source: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not to recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r), but other combinations are possible. Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts below 350 cells/microl; 2) When CD4 counts are between 350 and 500 cells/microl, therapy should be started in case of cirrhosis, chronic hepatitis C, high cardiovascular risk, HIV nephropathy, HIV viral load above 100,000 copies/ml, proportion of CD4 cells under 14%, and in people aged over 55; 3) Therapy should be deferred when CD4 are above 500 cells/microl, but could be considered if any of previous considerations concurs. Treatment should be initiated in case of hepatitis B requiring treatment and should be considered for reduce sexual transmission. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures but undetectable viral loads maybe possible with the new drugs even in highly drug experienced patients. Genotype studies are useful in these situations. Drug toxicity of ART therapy is losing importance as benefits exceed adverse effects. Criteria for antiretroviral treatment in acute infection, pregnancy and post-exposure prophylaxis are mentioned as well as the management of HIV co-infection with hepatitis B or C.

CONCLUSIONS

CD4 cells counts, viral load and patient co-morbidities are the most important reference factors to consider when initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized therapy approach in order to achieve undetectable viral load under any circumstances.

Treatment to prevent transmission of HIV-1

Antiretroviral therapy (ART) has the potential to prevent human immunodeficiency virus (HIV) transmission by reducing the concentration of HIV in blood and genital secretions. Indeed, mathematical models with favorable assumptions suggest the potential of ART to stop the spread of HIV infection. Empirical results from ecological and population-based studies and from several short-term observational studies involving HIV status-discordant heterosexual couples suggest that ART reduces the rate of HIV transmission. A multinational, randomized, controlled trial (National Institutes of Health HPTN052) examining the reliability and durability of ART as prevention of transmission in HIV status-discordant couples is under way. The latter and other studies also consider sexual risk-taking behavior and transmission of HIV-resistant variants when ART is used as prevention. Early HIV detection and treatment (ie, test and treat) are being considered as an important prevention strategy. In this article, we review the data supporting the use of ART to prevent HIV transmission and critically examine the public health implications of this strategy.

Nanotechnology-based systems for the treatment and prevention of HIV/AIDS

The HIV/AIDS pandemic is an increasing global burden with devastating health-related and socioeconomic effects. The widespread use of antiretroviral therapy has dramatically improved life quality and expectancy of infected individuals, but limitations of currently available drug regimens and dosage forms, alongside with the extraordinary adapting capacity of the virus, have impaired further success. Alongside, circumventing the escalating number of new infections can only be attained with effective and practical preventative strategies. Recent advances in the field of drug delivery are providing evidence that engineered nanosystems may contribute importantly for the enhancement of current antiretroviral therapy. Additionally, groundwork is also being carried out in the field nanotechnology-based systems for developing preventative solutions for HIV transmission. This manuscript reviews recent advances in the field of nanotechnology-based systems for the treatment and prevention of HIV/AIDS. Particular attention is given to antiretroviral drug targeting to HIV reservoirs and the usefulness of nanosystems for developing topical microbicides and vaccines.

A Qualitative Study of Providers' Perception of Adherence of Women Living with HIV/AIDS in Puerto Rico

This study examines healthcare providers' perceptions regarding experiences and factors that contribute to adherent and non-adherent behaviors to HIV treatment among women living with HIV infection in Puerto Rico and describes strategies implemented to improve adherence. Providers' accounts revealed that women with HIV infection are living "beyond their strengths" attempting to reconcile the burden of the illness and keep adherent. Factors putting women beyond their strengths and influencing non-adherence behavior were: gender-related demands, fear of disclosure, and treatment complexity. Strategies to improve adherence included: ongoing assessment, education, collaborative work, support groups, networking, disguising pills, readiness, and seeking medications outside their towns. Provider-patient interactions are critical for women's success and must assess all these factors in developing and providing health services.

Control of sexually transmitted infections and prevention of HIV transmission: mending a fractured paradigm

Control of sexually transmitted infections (STIs) is feasible, leads to improved sexual and reproductive health and contributes to preventing HIV transmission. The most advanced HIV epidemics have developed under conditions of poor STI control, particularly where ulcerative STIs were prevalent. Several countries that have successfully controlled STIs have documented stabilization or reversal of their HIV epidemics. STI control is a public health outcome measured by reduced incidence and prevalence. The means to achieve this include: (i) targeting and outreach to populations at greatest risk; (ii) promoting and providing condoms and other means of prevention; (iii) effective clinical interventions; (iv) an enabling environment; and (v) reliable data. Clinical services include STI case management, screening and management of STIs in sex partners. Syndromic case management is effective for most symptomatic curable STIs and screening strategies exist to detect some asymptomatic infections. Presumptive epidemiologic treatment of sex partners and sex workers complement efforts to interrupt transmission and reduce prevalence. Clinical services alone are insufficient for control since many people with STIs do not attend clinics. Outreach and peer education have been effectively used to reach such populations. STI control requires effective interventions with core populations whose rates of partner change are high enough to sustain transmission. Effective, appropriate targeting is thus necessary and often sufficient to reduce prevalence in the general population. Such efforts are most effective when combined with structural interventions to ensure an enabling environment for prevention. Reliable surveillance and related data are critical for designing and evaluating interventions and for assessing control efforts.

Strategies used in the detection of acute/early HIV infections. The NIMH Multisite Acute HIV Infection Study: I

Acute/early HIV infection plays a critical role in onward HIV transmission. Detection of HIV infections during this period provides an important early opportunity to offer interventions which may prevent further transmission. In six US cities, persons with acute/early HIV infection were identified using either HIV RNA testing of pooled sera from persons screened HIV antibody negative or through clinical referral of persons with acute or early infections. Fifty-one cases were identified and 34 (68%) were enrolled into the study; 28 (82%) were acute infections and 6 (18%) were early infections. Of those enrolled, 13 (38%) were identified through HIV pooled testing of 7,633 HIV antibody negative sera and 21 (62%) through referral. Both strategies identified cases that would have been missed under current HIV testing and counseling protocols. Efforts to identify newly infected persons should target specific populations and geographic areas based on knowledge of the local epidemiology of incident infections.

Lessons learned about behavioral science and acute/early HIV infection. The NIMH Multisite Acute HIV Infection Study: V

Acute/early HIV infection is a period of heightened HIV transmission and a window of opportunity for intervention to prevent onward disease transmission. The NIMH Multisite Acute HIV Infection (AHI) Study was an exploratory initiative aimed at determining the feasibility of recruiting persons with AHI into research, assessing their psychosocial and behavioral characteristics, and examining short-term changes in these characteristics. This paper reports on lessons learned in the study, including: (1) the need to establish the cost-effectiveness of AHI testing; (2) challenges to identifying persons with AHI; (3) the need to increase awareness of acute-phase HIV transmission risks; (4) determining the goals of behavioral interventions following AHI diagnosis; and (5) the need for "rapid response" public health systems that can move quickly enough to intervene while persons are still in the AHI stage. There are untapped opportunities for behavioral and medical science collaborations in these areas that could reduce the incidence of HIV infection.

The use of pooled viral load testing to identify antiretroviral treatment failure

BACKGROUND

To develop less costly methods to virologically monitor patients receiving antiretroviral therapy, we evaluated methods that use pooled blood samples and quantitative information available from viral load assays to monitor a cohort of patients on first-line antiretroviral therapy for virologic failure.

METHODS

We evaluated 150 blood samples collected after 6 months of therapy from participants enrolled in a San Diego primary infection program between January 1998 and January 2007. Samples were screened for virologic failure with individual viral load testing, 10 x 10 matrix pools and minipools of five samples. For the pooled platforms (matrix and minipools), we used a search and retest algorithm based on the quantitative viral load data to resolve samples that remained ambiguous for virologic failure. Viral load thresholds were more than 500 and more than 1500 copies/ml for the matrix and more than 250 and more than 500 copies/ml for the minipool. Efficiency, accuracy and result turnaround times were evaluated.

RESULTS

Twenty-three percent of cohort samples were detectable at more than 50 HIV RNA copies/ml. At an algorithm threshold of more than 500 HIV RNA copies/ml, both minipool and matrix methods used less than half the number of viral load assays to screen the cohort, compared with testing samples individually. Both pooling platforms had negative predictive values of 100% for viral loads of more than 500 HIV RNA copies/ml and at least 94% for viral loads of more than 250 HIV RNA copies/ml.

CONCLUSION

In this cohort, both pooling methods improved the efficiency of virologic monitoring over individual testing with a minimal decrease in accuracy. These methods may allow for the induction and sustainability of the virologic monitoring of patients receiving antiretroviral therapy in resource-limited settings.

Detection of individuals with acute HIV-1 infection using the ARCHITECT HIV Ag/Ab Combo assay

BACKGROUND

We evaluated use of the ARCHITECT HIV Ag/Ab Combo assay (HIV Combo; Abbott Diagnostics; available for sale outside the United States only) for detection of acute HIV infection.

METHODS

Samples were obtained from a behavioral intervention study (EXPLORE). HIV-uninfected men who have sex with men were enrolled and tested for HIV infection every 6 months. Samples from seroconverters collected at their last seronegative visit (n = 217) were tested individually using 2 HIV RNA assays. Samples with detectable HIV RNA were classified as acute and were tested with HIV Combo. Samples from the enrollment visit (n = 83) and the time of HIV seroconversion (n = 219) were tested with HIV Combo as controls.

RESULTS

Twenty-one samples (9.7%) from the last seronegative visit had detectable HIV RNA and were classified as acute. HIV Combo was positive for 13 of the acute samples (61.9%). Samples not detected by HIV Combo had viral loads of 724-15,130 copies per milliliter. Expected results were obtained for positive and negative controls tested with HIV Combo.

CONCLUSIONS

HIV Combo detected nearly two thirds of acute HIV infections identified in this high-risk population by non-pooled HIV RNA assays. HIV Combo may be useful for high-throughput screening to identify individuals with acute HIV infection.

The potential role of biomarkers in HIV preventive vaccine trials

BACKGROUND

Successful conduct of HIV vaccine efficacy trials entails identification and enrollment of at-risk populations, assessment of appropriate end points as measures of vaccine efficacy for prevention of HIV acquisition, and amelioration of disease course among infected vaccinees, as well as identification of potential confounders or effect modifiers. Although not invariably useful and bringing their own cost in terms of measurement and validation, a variety of biomarkers may aid at each stage of trial conduct.

METHODS

A review of selected articles, chosen based on quality, relevance of the biomarker to HIV vaccine trials, and availability of the publication, was conducted. The authors also drew experience from current trials and other planned or ongoing trials.

CONCLUSIONS

Biomarkers are available to assess HIV incidence in potential study populations, but care is needed in interpreting results of these assays. During trial conduct, sexually transmitted infections such as herpes simplex virus type 2 may act as effect modifiers on primary and secondary end points, including HIV incidence and set point viral load. The utility of sexually transmitted infection biomarkers will likely depend heavily on local epidemiology at clinical trial sites. Analyses from recent large HIV vaccine efficacy trials point to the complexities in interpreting trial results and underscore the potential utility of biomarkers in evaluating confounding and effect modification.

Targeted testing for acute HIV infection in North Carolina

BACKGROUND

Persons with acute HIV infection contribute disproportionately to HIV transmission. The identification of these persons is a critical public health challenge. We developed targeted approaches for detecting HIV RNA in persons with negative serological tests.

METHODS

Persons undergoing publicly funded HIV testing in North Carolina between October 2002 and April 2005 were included in this cross-sectional study. We used logistic regression to develop targeted testing approaches. We also assessed simple approaches based on clinic type and geography. Algorithm development used persons with recent HIV infection, determined by a detuned enzyme-linked immunosorbent assay. Validation used persons with acute HIV infection, identified with an HIV RNA pooling procedure.

RESULTS

Among 215 528 eligible persons, 232 persons had recent HIV infection and 44 had acute HIV infection. A combination of five indicators (testing site, sexual preference, sex with a person with HIV infection, county HIV incidence, and race) identified 92% of recent infections when testing 50% of the population. In validation among persons with acute HIV infection, this indicator combination had sensitivities of 98% in years 1 and 2 and 88% in year 3. A simple combination of testing site and county performed nearly as well [development (recent infections): sensitivity = 95%; validation (acute infections): sensitivity = 86% in years 1 and 2; 81% in year 3; cut-off established for testing 50% of population.]

CONCLUSION

Acute HIV infection can be identified accurately using targeted testing. Simple approaches for identifying the types of clinics and geographical areas where infections are concentrated may be logistically feasible and cost-efficient.

Identification of primary HIV-1C infection in Botswana

Methods for identification of primary HIV infections seem increasingly important to understand pathogenesis, and to prevent transmission, which is particularly efficient during acute infection. Most current algorithms for HIV testing are based on detection of HIV antibodies and are unable to identify early infections before seroconversion. The efficiency of prospective cohorts, which is a standard approach for identifying primary HIV-1 infection, depends on a variety of epidemiological and cultural factors including HIV incidence and stigma and, not surprisingly, varies significantly in different geographical areas. We report a voluntary counseling and testing (VCT)-based approach to identifying primary HIV-1C infection that was developed as part of a primary HIV-1 subtype C infection study in Botswana. The referral strategy was based on: (1) collaboration with VCT centers at city clinics operated by the Ministry of Health; (2) partnering with the busiest non-government VCT center; (3) educating healthcare workers and the community about primary HIV infection; and (4) pairing with diverse VCT providers, including NGOs and private-sector organizations. Acute HIV-1 infections were defined by a negative HIV-1 serology combined with a positive HIV-1 RT-PCR test. Recent HIV-1 infections were identified by detuned EIA testing according to the classic STARTH algorithm. The VCT-based referral strategy resulted in the successful identification of 57 cases of acute and early HIV infection. A referral strategy of expanded VCT with viral RNA (Ribonucleic acid) testing to a national program in Botswana may be a promising approach for identification of primary HIV infections on a countrywide level. The program should offer VCT with viral RNA testing to the general public, facilitate proper counseling and risk reduction, and allow initiation of early HAART, and may reduce new viral transmissions.

Three-dimensional array-based group testing algorithms

We derive the operating characteristics of three-dimensional array-based testing algorithms for case identification in the presence of testing error. The operating characteristics investigated include efficiency (i.e., expected number of tests per specimen) and error rates (e.g., sensitivity, specificity, positive, and negative predictive values). The methods are illustrated by comparing the proposed algorithms with previously studied hierarchical and two-dimensional array algorithms for detecting recent HIV infections in North Carolina. Our results indicate that three-dimensional array-based algorithms can be more efficient and accurate than previously proposed algorithms in settings with test error and low prevalence.

Prevention of the sexual transmission of HIV-1: preparing for success

There are four opportunities for HIV prevention: before exposure, at the moment of exposure, immediately after exposure, and as secondary prevention focused on infected subjects. Until recently, most resources have been directed toward behavioral strategies aimed at preventing exposure entirely. Recognizing that these strategies are not enough to contain the epidemic, investigators are turning their attention to post-exposure prevention opportunities. There is increasing focus on the use of ART–either systemic or topical (microbicides)–to prevent infection at the moment of exposure. Likewise, there is growing evidence that ART treatment of infected people could serve as prevention as well. A number of ongoing clinical trials will shed some light on the potential of these approaches. Above all, prevention of HIV requires decision-makers to focus resources on strategies that are most effective. Finally, treatment of HIV and prevention of HIV must be considered and deployed together.

New challenges for mathematical and statistical modeling of HIV and hepatitis C virus in injecting drug users

Injecting drug users are not only driving blood-borne transmission of HIV and hepatitis C virus but also likely drive sexual transmission of HIV in large parts of the world. Mathematical and statistical modeling can provide important insights in these epidemiological processes and on the potential impact of interventions but have been little used to date. This review aims to discuss the potential areas of application of modeling in the field of viral infections in injecting drug users. After reviewing key examples of published modeling work on HIV and hepatitis C virus in injecting drug users, we discuss recent developments in the epidemiology, diagnosis, treatment and prevention of these infections. In particular, new methods for the diagnosis of early HIV infection, new antivirals for a more effective treatment of HIV, hepatitis B and hepatitis C virus infections, new concepts in design and surveillance of interventions for drug users and increasing possibilities of molecular typing of pathogens are changing the questions and decisions for public health policy makers who deal with drug-related infectious diseases. Research including mathematical modeling is needed to understand the impact of new diagnostic tools, new treatment options and combined intervention strategies on the epidemiology of viral infections in injecting drug users. Methodological advances in mathematical modeling are required to adequately approach some of the ensuing research questions. Modeling has much to offer for solving urgent policy questions, but current levels of funding in modeling research are insufficient and need to be scaled up to make better use of these possibilities.

Rapid detection of HIV-1 by reverse-transcription, loop-mediated isothermal amplification (RT-LAMP)

A rapid, cost-effective diagnostic or confirmatory test for the detection of early HIV-1 infection is highly desired, especially for use in resource-poor or point-of-care settings. The reverse-transcription loop-mediated isothermal amplification (RT-LAMP) technology has been evaluated for the detection of HIV-1 DNA and RNA, using six RT-LAMP primers designed against highly conserved sequences located within the protease and p24 gene regions. Amplification from lab-adapted HIV-1 DNA and RNA was detected as early as 30 min, with maximum sensitivity of 10 and 100 copies per reaction, respectively, reached at 60 min. Comparable sensitivity was observed with extracted nucleic acid from plasma and blood samples of HIV-1-infected individuals. Furthermore, the RT-LAMP procedure was modified for the direct detection of HIV-1 nucleic acid in plasma and blood samples, eliminating the need for an additional nucleic acid extraction step and reducing the overall procedure time to approximately 90 min.

Integrating multidimensional HIV prevention programs into healthcare settings

Effective secondary prevention programs to reduce HIV transmission risk-relevant behaviors among HIV-infected individuals must go beyond the traditional, common sense prevention components to develop biomedically and epidemiologically informed behavioral interventions as part of comprehensive, integrated, multidisciplinary HIV care. Incorporating and expanding on the Serostatus Approach to Fighting the Epidemic, a five-pronged strategy set forth by the Centers for Disease Control and Prevention in 2001, we discuss recent findings from the biomedical sciences on viral and host factors that influence infectiousness to support the idea that the most proactive prevention programs will explicitly integrate biomedical interventions and approaches designed to reduce infectiousness, and thus the sexual transmission of HIV. Based on studies of emerging and spreading drug-resistant HIV variants, we have posited the potential development of biodisparity as the biological entrenchment of disparities in socioeconomic status, access to care, and HIV risk-relevant behaviors that differentially affect minorities living with HIV in the US. It is clear that creative approaches based on an expanded behavioral medicine interface with the latest HIV biomedical and epidemiological research are needed to enhance the efficacy of HIV secondary prevention.

Critical issues in mucosal immunity for HIV-1 vaccine development

Development of a safe and effective vaccine for HIV-1 infection is a critical global priority. However, the nature of host-virus interactions that lead to early immunosuppression and CD4 depletion, HIV-1 diversity, and the inability of the immune system to eliminate the latently infected CD4 pool of cells has to date thwarted successful vaccine development. Moreover, both the initial antibody-inducing vaccine (protein envelope gp120) and cell-mediated vaccine (recombinant adenovirus containing HIV-1 genes) strategies have failed in efficacy trials, and the latter cell-mediated vaccine appeared to have caused enhanced HIV-1 acquisition. Thus basic and translational research to understand why current vaccines have failed and elucidation of new mechanisms of virus control at mucosal surfaces is essential for eventual successful development of a preventive HIV-1 vaccine.

Treatment response in acute/early infection versus advanced AIDS: equivalent first and second phases of HIV RNA decline

OBJECTIVE

Compare the initial phases of virologic decay when acute/early and advanced HIV-infected adults are administered the same treatment regimen.

DESIGN

Mathematical modeling of a previously completed prospective treatment pilot study involving treatment-naive patients with early and advanced immunosuppression.

METHODS

We analyzed data from a treatment protocol in which 18 individuals with acute or recent HIV-1 seroconversion and six patients with advanced AIDS were administered the same four-drug antiretroviral regimen. Initial treatment responses were compared by fitting a mathematical model to frequent viral load measurements in order to calculate the first and second phase kinetics of viral clearance, and also by comparing viral load suppression over 24 weeks. Patients were also comprehensively compared in terms of protease inhibitor drug levels, HIV-specific immune responses at baseline, and the presence of drug resistance-conferring mutations.

RESULTS

There was no statistically meaningful difference in first phase clearance of comparable high-level viremia in the two groups, whether protease inhibitor levels were inserted into the model or 100% antiviral drug effectiveness was assumed. In contrast, acute/early patients had inferior sustained responses than advanced patients, reflecting erratic adherence.

CONCLUSIONS

Despite many years of intervening immune destruction, the initial virologic decay on therapy appears to be the same at the extremes of the HIV disease spectrum.

Genetic variation in mother-child acute seroconverter pairs from Zambia

OBJECTIVE

To characterize the envelope (Env) glycoprotein of HIV-1 in mother-infant pairs (MIP) that underwent near simultaneous or acute-phase seroconversion, we examined the Env sequence of the transmitted viruses and compare viral evolution within the pair.

DESIGN

Three MIP from a Zambian cohort that seroconverted at the same sampling time were identified and followed longitudinally.

METHODS

The V1-V5 region of the HIV-1 Env gene was sequenced for each sample collected. Phylogenetic and population genetics analyses were carried out to subtype the viruses, estimate relationships among viral genotypes, and compare molecular evolution between the viral populations.

RESULTS

Genetic analyses demonstrated a close intrapair relationship between viral sequences from each MIP. Transmission involved several closely related viral genotypes and did not result in a reduction in viral diversity. Amino acid changes were not evenly distributed along Env V1-V5 but concentrated in concordant areas within each MIP. Several positions under positive selection were shared between the MIP viruses. Interestingly, selective pressure on the virus was higher in the infants than in the mothers.

CONCLUSIONS

In contrast to most cases of perinatal transmission of HIV-1 from chronically infected mothers, there is no evidence of a genetic bottleneck in the transmitted viruses in these three instances of acute seroconversion. The longitudinal changes in the amino acids are in similar positions in Env for the MIP, suggesting shared evolutionary constrains among the closely related viruses infecting the MIP; such constrains may lead to similar genetic changes in the virus in two different hosts.

The spread, treatment, and prevention of HIV-1: evolution of a global pandemic

The most up-to-date estimates demonstrate very heterogeneous spread of HIV-1, and more than 30 million people are now living with HIV-1 infection, most of them in sub-Saharan Africa. The efficiency of transmission of HIV-1 depends primarily on the concentration of the virus in the infectious host. Although treatment with antiviral agents has proven a very effective way to improve the health and survival of infected individuals, as we discuss here, the epidemic will continue to grow unless greatly improved prevention strategies can be developed and implemented. No prophylactic vaccine is on the horizon. However, several behavioral and structural strategies have made a difference--male circumcision provides substantial protection from sexually transmitted diseases, including HIV-1, and the application of antiretroviral agents for prevention holds great promise.

Population prevalence of reported and unreported HIV and related behaviors among the household adult population in New York City, 2004

BACKGROUND

Surveillance for HIV likely underestimates infection among the general population: 25% of US residents are estimated to be unaware of their HIV infection.

OBJECTIVE

To determine the prevalence of HIV infection and risk behaviors among New York City (NYC) adults and compare these with surveillance findings.

METHODS

The NYC Health and Nutrition Examination Survey (HANES) provided the first opportunity to estimate population-based HIV prevalence among NYC adults. It was conducted in 2004 among a representative sample of adults > 20 years. Previously reported HIV infection was identified from the NYC HIV/AIDS Surveillance Registry. A blinded HIV serosurvey was conducted on archived blood samples of 1626 NYC HANES participants. Data were used to estimate prevalence for HIV infection, unreported infections, high-risk activities, and self-perceived risk.

RESULTS

Overall, 18.1% engaged in one or more risky sexual/needle-use behaviors, of which 92.2% considered themselves at low or no risk of HIV or another sexually transmitted disease. HIV occurred in 21 individuals (prevalence 1.4%; 95% confidence interval (CI), 0.8-2.5]; one infection (5%; 95% CI, 0.7-29.9) was not reported previously and possibly undiagnosed. HIV infection was significantly elevated in those with herpes simplex virus 2 (4%), men who have sex with men (14%), and needle-users (21%) (P < 0.01).

CONCLUSIONS

Among NYC adults, HIV prevalence was consistent with surveillance findings overall. The proportion of unreported HIV was less than estimated nationally, but findings were limited by sample size. Most adults with risky behaviors perceived themselves to be at minimal risk, highlighting the need for risk reduction and routine HIV screening.

HIV testing and counselling for women attending child health clinics: an opportunity for entry to prevent mother-to-child transmission and HIV treatment

This study assessed the potential for HIV testing at child health clinics to increase knowledge of HIV status, and entry to infant feeding counselling and HIV treatment. At a provincial hospital in Mombasa, Kenya, HIV testing and counselling were offered to women bringing their child for immunization or acute care services. Most women said HIV testing should be offered in these clinics (472/493, 95.7%), with many citing the benefits of regular testing and entry to prevent mother-to-child transmission. Of 500 women, 416 (83.4%) received test results, 97.6% on the same day. After 50 participants, point-of-care testing replaced laboratory-based rapid testing. Uptake increased 2.6 times with point-of-care testing (95% confidence interval = 1.4–5.1; P = 0.003). Of 124 women who had not accessed HIV testing during pregnancy, 98 tested in the study (79.0%). Measured by uptake and attitudes, HIV testing in child health clinics is acceptable. This could optimize entry into HIV treatment, infant feeding counselling and family planning services.

Improved detection of acute HIV-1 infection in sub-Saharan Africa: development of a risk score algorithm

OBJECTIVE

Individuals with acute (preseroconversion) HIV infection (AHI) are important in the spread of HIV. The identification of AHI requires the detection of viral proteins or nucleic acids with techniques that are often unaffordable for routine use. To facilitate the efficient use of these tests, we sought to develop a risk score algorithm for identifying likely AHI cases and targeting the tests towards those individuals.

DESIGN

A cross-sectional study of 1448 adults attending a sexually transmitted infections (STI) clinic in Malawi.

METHODS

Using logistic regression, we identified risk behaviors, symptoms, HIV rapid test results, and STI syndromes that were predictive of AHI. We assigned a model-based score to each predictor and calculated a risk score for each participant.

RESULTS

Twenty-one participants (1.45%) had AHI, 588 had established HIV infection, and 839 were HIV-negative. AHI was strongly associated with discordant rapid HIV tests and genital ulcer disease (GUD). The algorithm also included diarrhea, more than one sexual partner in 2 months, body ache, and fever. Corresponding predictor scores were 1 for fever, body ache, and more than one partner; 2 for diarrhea and GUD; and 4 for discordant rapid tests. A risk score of 2 or greater was 95.2% sensitive and 60.5% specific in detecting AHI.

CONCLUSION

Using this algorithm, we could identify 95% of AHI cases by performing nucleic acid or protein tests in only 40% of patients. Risk score algorithms could enable rapid, reliable AHI detection in resource-limited settings.

Amplified transmission of HIV-1: comparison of HIV-1 concentrations in semen and blood during acute and chronic infection

OBJECTIVES

This study was conducted to compare viral dynamics in blood and semen between subjects with antibody negative, acute HIV-1 infection and other subjects with later stages of infection.

DESIGN

A prospective cohort study was embedded within a cross-sectional study of HIV screening in a Lilongwe, Malawi STD clinic.

METHODS

Blood samples from HIV antibody negative or indeterminate volunteers were used to detect HIV RNA in plasma using a pooling strategy. Blood and seminal plasma HIV-1 RNA concentrations were measured over 16 weeks.

RESULTS

Sixteen men with acute HIV infection and 25 men with chronic HIV infection were studied. Blood viral load in subjects with acute HIV infection was highest about 17 days after infection (mean +/- SE, 6.9 +/- 0.5 log10 copies/ml), while semen viral load peaked about 30 days after infection (4.5 +/- 0.4 log10 copies/ml). Semen viral load declined by 1.7 log10 to a nadir by week 10 of HIV infection. Semen and blood viral loads were more stable in chronically infected subjects over 16 weeks. Higher semen levels of HIV RNA were noted in subjects with low CD4 cell counts.

CONCLUSIONS

These results provide a biological explanation for reported increases in HIV transmission during the very early (acute) and late stages of infection. Recognizing temporal differences in HIV shedding in the genital tract is important in the development of effective HIV prevention strategies.

Coma as a presenting symptom of primary HIV infection

Primary HIV infection (PHI) is symptomatic in 50-90% of patients. The diagnosis, however, is seldom made at first presentation. This is probably because of the multifaceted and unspecific manifestations, the omission to perform adequate diagnostic testing and the failure to assess risks for PHI. Meningoencephalitis has been described as a fairly common presenting condition in PHI, with nuchal rigidity, fatigue, photophobia and headache; therefore, PHI should be considered in the differential diagnosis of aseptic meningitis. We present the case of a man with acute coma and a presumptive diagnosis of viral encephalitis in whom serological testing showed HIV encephalitis during PHI.

[Recommendations from the GESIDA/Spanish AIDS Plan regarding antiretroviral treatment in adults with human immunodeficiency virus infection (update January 2007)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy (ART) recommendations for adult patients infected with the human immunodeficiency virus (HIV-1).

METHODS

To formulate these recommendations, a panel composed of members of the Grupo de Estudio de Sida (GESIDA; AIDS Study Group) and the Plan Nacional sobre el Sida (PNS; Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of HIV, the safety and efficacy findings from clinical trials, and the results from cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings over the last years. Three levels of evidence were defined according to the source of the data: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r). Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4+ lymphocyte counts and plasma viral load, as follows: 1) therapy should be started in patients with CD4+ counts of < 200 cells/microl; 2) therapy should be started in most patients with CD4+ counts of 200-350 cells/microl, although it can be delayed when CD41 count persists at around 350 cells/microL and viral load is low, and 3) initiation of therapy can be delayed in patients with CD4+ counts of > 350 cells/microL. The initial objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining the antiviral response. Therapeutic options are limited with the development of cross resistance and ART failure. Genotype studies are useful in these cases. More information regarding the studies analyzed and the panel recommendations for adherence, toxicity, treatment during pregnancy, patients with hepatitis B or C virus co-infection, and post-exposure prophylaxis can be accessed at www.gesida.seimc.org.

CONCLUSIONS

CD4+ lymphocyte count is the most important reference factor for initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized approach to therapy.

When to start antiretroviral therapy

The current literature is controversial in providing evidence to determine the optimal time to initiate therapy among patients with HIV. However, there is evidence that initiating early treatment might provide benefits by treating primary HIV infection, preserving normal immune function, suppressing HIV viral replication, deferring clinical progression, and reducing HIV transmission. The biggest challenges in initiating treatment early are issues related with long-term management, including toxicities, adherence, and drug resistance. However, the availability of superior new antiretroviral drugs and simplified regimens, the development of effective treatment strategy, and further improvement of adherence through directly observed treatment are addressing the issues and changing the balance towards earlier treatment.

Is HIV-1 evolving to a less virulent form in humans?

During the rapid spread of HIV-1 in humans, the main (M) group of HIV-1 has evolved into ten distinct subtypes, undergone countless recombination events and diversified extensively. The impact of this extreme genetic diversity on the phenotype of HIV-1 has only recently become a research focus, but early findings indicate that the dominance of HIV-1 subtype C in the current epidemic might be related to the lower virulence of this subtype compared with other subtypes. Here, we explore whether HIV-1 has reached peak virulence or has already started the slow path to attenuation.

Virological characterization of patients treated early is able to control HIV-1 replication after multiple cycles of structured therapy interruption

This study aimed to define clinical and virological parameters associated with spontaneous control of HIV replication in patients having initiated HAART during primary HIV infection, who underwent structured therapy interruption by two protocols with either fixed or HIV viremia-guided scheme. At the end of the protocol all patients were changed to viremia-guided scheme and observed for 12 months (follow-up). Patients maintaining HIV viremia below the indications for resumption of HAART during the follow-up, were defined controllers, those who had to resume HAART were defined non-controllers. The following parameters were examined: pre-interruption therapy duration, CD4(+), HIV RNA, proviral DNA, evolution of viral quasispecies. No specific advantage was conferred by either interruption of structured therapy in the proportion of controllers and non-controllers. Pre-HAART and zenith CD4(+), pre-therapy interruption, HAART duration, but not pre-HAART HIV RNA, were significantly higher in controllers as compared to non-controllers. HIV RNA levels after the first interruption cycle of therapy were significantly lower in controllers than in non-controllers. Proviral DNA levels were also lower in controllers at this time point. HIV RNA and proviral DNA levels associated with the last interruption of therapy cycle were not different from those associated with the first cycle, and, in spite of multiple waves of virus rebound, very few gag quasispecies variants emerged in each patient. The data suggest that pre-treatment clinical parameters and virological events associated with the first viral rebound are crucial factors in determining the ability to control viral replication after multiple cycles of interruption of treatment.

Approaching "HIV elimination": Interventions for acute HIV infection

Recent observations from several groups suggest that individuals with acute (antibody negative) HIV infections (AHI) may present for "routine" HIV testing in unanticipated numbers. Most of these papers have highlighted the use of group testing strategies to screen antibody negative testing sera for HIV RNA using nucleic acid amplification tests. At the same time, accumulating evidence indicates that AHI is a time of briefly, but substantially elevated risk for transmission of HIV. In this paper, we review these new data with attention to their implications for HIV prevention strategies. By calling attention to a subset of patients that are both recently infected and at transiently very high risk of transmitting their new infection to partners, AHI detection makes it possible to use traditional, network notification-based public health strategies effectively in the fight against HIV.

Primary human immunodeficiency virus type 1 infection: clinical, virological and immunological characteristics of 75 patients (1997-2003)

OBJECTIVES

To describe the epidemiological and clinical characteristics and the evolution of a cohort of patients with primary HIV-1 infection from the Barcelona area.

METHODS

Prospective cohort study of HIV-infected patients diagnosed with primary HIV infection in a tertiary hospital in Barcelona (Spain) from 1997 through 2003. Descriptive analysis of epidemiological and clinical characteristics and effect of highly active antiretroviral treatment (HAART) on outcome.

RESULTS

A total of 75 patients were diagnosed, accounting for 2.9% of the total of newly diagnosed HIV patients during the same time period. Eighty-one percent of the patients were males and the median age was 30 years (IQR 26-38). The most frequent transmission route was homosexual (72%), followed by heterosexual (17%) and intravenous drug abuse (11%). Seventy-seven percent of patients presented symptoms, the most frequent being fever (98%), asthenia (86%), arthralgia-myalgia (65%), lymphadenopathy (55%), night sweats (48%) and rash. Sixty-five percent started HAART, although the proportion of patients that received HAART decreased from 79% during the period 1997-2000 to 49% during the period 2001-2003 (p < 0.01). After a median follow-up of 37 months (IQR 26-66), one patient died and eight cases were lost to follow-up. The patients who did not receive HAART had a higher probability of immunological or clinical deterioration during the follow-up when compared to the group that received HAART (42.3% versus 12.3%; p < 0.001). In treated patients, dyslipidemia and lipodystrophy were diagnosed in 58% and 37% of cases, respectively.

CONCLUSIONS

Primary HIV-1 infection was diagnosed more frequently in homosexual males, and its clinical characteristics were similar to those observed in previous studies. HAART given during primary HIV infection was effective, but was associated with a high percentage of adverse effects.

Containing HIV/AIDS in India: the unfinished agenda

India's HIV epidemic is not yet contained and prevention in populations most at risk (high-risk groups) needs to be enhanced and expanded. HIV prevalence as measured through surveillance of antenatal and sexually transmitted disease clinics is the chief source of information on HIV in India, but these data cannot provide real insight into where transmission is occurring or guide programme strategy. The factors that influence the Indian epidemic are the size, behaviours, and disease burdens of high-risk groups, their interaction with bridge populations and general population sexual networks, and migration and mobility of both bridge populations and high-risk groups. The interplay of these forces has resulted in substantial epidemics in several pockets of many Indian states that could potentially ignite subepidemics in other, currently low prevalence, parts of the country. The growth of HIV, unless contained, could have serious consequences for India's development. India's national response to HIV began in 1992 and has shown early success in some states. The priority is to build on those successes by increasing prevention coverage of high-risk groups to saturation level, enhancing access and uptake of care and treatment services, ensuring systems and capacity for evidence-based programming, and building in-country technical and managerial capacity.

The development and utility of a clinical algorithm to predict early HIV-1 infection

The association between self-reported clinical factors and recent HIV-1 seroconversion was evaluated in a prospective cohort of 4652 high-risk participants in the HIV Network for Prevention Trials (HIVNET) Vaccine Preparedness Study. Eighty-six individuals seroconverted, with an overall annual seroconversion rate of 1.3 per 100 person-years. Four self-reported clinical factors were significantly associated with HIV-1 seroconversion in multivariate analyses: recent history of chlamydia infection or gonorrhea, recent fever or night sweats, belief of recent HIV exposure, and recent illness lasting > or =3 days. Two scoring systems, based on the presence of either 4 or 11 clinical factors, were developed. Sensitivity ranged from 2.3% (with a positive predictive value of 12.5%) to 72.1% (with a positive predictive value of 1%). Seroconversion rates were directly associated with the number of these clinical factors. The use of scoring systems comprised of clinical factors may aid in detecting early and acute HIV-1 infection in vaccine and microbicide trials. Organizers can educate high-risk trial participants to return for testing during interim visits if they develop these clinical factors. Studying individuals during early and acute HIV-1 infection would allow scientists to investigate the impact of the intervention being studied on early transmission or pathogenesis of HIV-1 infection.

Amplified transmission of HIV-1: missing link in the HIV pandemic

Sexual transmission of HIV most closely reflects the concentration of HIV in the genital tract; HIV in the genital tract of subjects with acute HIV and some "classical" STDS is 8-10 times greater than in control subjects. It seems likely that these latter subjects lead to spread of HIV. Accordingly, the state of North Carolina committed to HIV testing that detects subjects with acute, recent, and established infection. We tested 109,500 samples over 9 months. We found 563 people with undiagnosed HIV infection. The majority of subjects were in STD clinics. This included 23 subjects with (pre-seroconversion) acute HIV infection (HIV RNA positive, antibody negative). The median blood HIV was 209,000 copies/ml, more than 10 times higher than in subjects with established HIV infection. Recognizing the increased number of subjects with unrecognized acute HIV infection in STD clinics, we conducted similar studies in STD Clinics in Malawi and South Africa. Between 1 and 2% of subjects had undetected acute HIV infection. The median viral burden in blood of subjects in Malawi was greater than 1,000,000 copies/ml. STDS and HIV are often co-transmitted, and STDS set the stage for subsequent HIV transmission. Prevention of sexual transmission of HIV likely requires maximal suppression of genital tract HIV viral burden, either through treatment of STDS or use of antiretroviral agents.

Primary HIV-1 infection sets the stage for important B lymphocyte dysfunctions

OBJECTIVES

To investigate the effects of primary HIV-1 infection (PHI) and of two antiretroviral therapies [highly active antiretroviral therapy (HAART) or reverse transcriptase inhibitors (RTI)] on activation, differentiation and survival of B cells.

METHODS

Naive and memory B cells from three groups [PHI (31), chronic infection (26) and healthy donors (12)] were studied for surface expression of Fas, LAIR-1, CD70, intracellular expression of Bcl-2 and spontaneous apoptosis. Fluorescence activated cell sorting (IgD+IgM+CD19+CD27+) and short-term cell culture to analyse induction of CD25 on B cells were performed in five patients with PHI. Patients with PHI were sampled at baseline, and after 1 and 6 months of therapy. Results were analysed by parametric and non-parametric tests and by mathematical modelling.

RESULTS

In PHI, B cells were significantly decreased; naive and memory B lymphocytes showed a high degree of activation, manifested by hypergammaglobulinaemia, altered expression of Fas and LAIR-1, and high rate of spontaneous apoptosis. Antiretroviral treatment improved the activation/differentiation status of B cells, reduced apoptosis to levels comparable to those in healthy individuals and restored the ability of B cells to respond to T cell-dependent activation. B cells showed slightly better recovery in patients taking HAART than in those taking RTI. Decreased IgM-positive memory B cells and lower induction of CD25 expression on B cells upon T cell activation at diagnosis of PHI was shown in five patients tested. These parameters normalized after 6 months of therapy.

CONCLUSION

B cell dysfunctions found in chronic HIV-1 infection appear during PHI and initiation of antiretroviral therapy early during infection may help to preserve the B cell compartment.

[Advances in the diagnosis and treatment of acute human immunodeficiency virus type 1 (HIV-1) infection]

According the WHO there are about 14,000 new HIV infections a day. However, in a few cases the diagnosis will be made in the acute phase of the disease. Acute HIV infection is the period between infection with the virus and complete seroconversion, defined by a positive Western blot test. This period lasts approximately 30 days and most patients (40-90%) have mild clinical manifestations (fever, rash, pharyngitis, mucosal ulcers, among others) for 2 weeks which, because they are nonspecific, can be confused with other community-acquired infections. Microbiological diagnosis is based on the absence of serum antibodies (negative ELISA test) together with a positive HIV viral load in plasma (> 10,000 copies/ml). Diagnosis of acute HIV infection is important for several reasons: firstly, from the epidemiological point of view, this is the period with the highest rates of HIV transmission and identification of new HIV infections reveals the growth of the epidemic and the transmission rates of resistant HIV strains, which in Spain is about 10%; secondly, from the immunopathological point of view, this period provides a unique opportunity to study the virological, immunological and genetic mechanisms that play a role in the transmission and pathogenesis of this disease; and thirdly, therapeutically, starting antiretroviral therapy during this phase could alter the natural history of the disease. However, this is a controversial issue and currently most guidelines recommend treatment only if these patients can be included in clinical trials or if they show lasting or severe clinical manifestations.