Recent Human Immunodeficiency Virus Infection Research Articles

A new approach to prevent HIV transmission: Project Protect intervention for recently infected individuals

Past research suggests that as many as 50% of onward human immunodeficiency virus (HIV) transmissions occur during acute and recent HIV infection. It is clearly important to develop interventions which focus on this highly infectious stage of HIV infection to prevent further transmission in the risk networks of acutely and recently infected individuals. Project Protect tries to find recently and acutely infected individuals and prevents HIV transmission in their risk networks. Participants are recruited by community health outreach workers at community-based HIV testing sites and drug users' community venues, by coupon referrals and through referrals from AIDS clinics. When a network with acute/recent infection is identified, network members are interviewed about their risky behaviors, network information is collected, and blood is drawn for HIV testing. Participants are also educated and given prevention materials (condoms, syringes, educational materials); HIV-infected participants are referred to AIDS clinics and are assisted with access to care. Community alerts about elevated risk of HIV transmission are distributed within the risk networks of recently infected. Overall, 342 people were recruited to the project and screened for acute/recent HIV infection. Only six index cases of recent infection (2.3% of all people screened) were found through primary screening at voluntary counseling and testing (VCT) sites, but six cases of recent infection were found through contact tracing of these recently infected participants (7% of network members who came to the interview). Combining screening at VCT sites and contact tracing the number of recently infected people we located as compared to VCT screening alone. No adverse events were encountered. These first results provide evidence for the theory behind the intervention, i.e., in the risk networks of recently infected people there are other people with recent HIV infection and they can be successfully located without increasing stigma for project participants.

The Recency Period for Estimation of Human Immunodeficiency Virus Incidence by the AxSYM Avidity Assay and BED-Capture Enzyme Immunoassay in the Republic of Korea

ObjectivesMeasurement of the incidence of the human immunodeficiency virus (HIV) is very important for epidemiological studies. Here, we determined the recency period with the AxSYM avidity assay and the BED-capture enzyme immunoassay (BED-CEIA) in Korean seroconverters. MethodsTwo hundred longitudinal specimens from 81 seroconverters with incident HIV infections that had been collected at the Korea National Institute of Health were subjected to the AxSYM avidity assay (cutoff = 0.8) and BED-CEIA (cutoff = 0.8). The statistical method used to estimate the recency period in recent HIV infections was nonparametric survival analyses. Sensitivity and specificity were calculated for 10-day increments from 120 days to 230 days to determine the recency period. ResultsThe mean recency period of the avidity assay and BED-CEIA using a survival method was 158 days [95% confidence interval (CI), 135–181 days] and 189 days (95% CI, 170–208 days), respectively. Based on the use of sensitivity and specificity, the mean recency period for the avidity assay and BED-CEIA was 150 days and 200 days, respectively. ConclusionWe determined the recency period to estimate HIV incidence in Korea. These data showed that the nonparametric survival analysis often led to shorter recency periods than analysis of sensitivity and specificity as a new method. These findings suggest that more data from seroconverters and other methodologies are needed to determine the recency period for estimating HIV incidence.

Transmitted human immunodeficiency virus-1 drug resistance in a cohort of men who have sex with men in Belo Horizonte, Brazil - 1996-2012

The presence of transmitted human immunodeficiency virus (HIV)-1 drug-resistance (TDR) at the time of antiretroviral therapy initiation is associated with failure to achieve viral load (VL) suppression. Here, we report TDR surveillance in a specific population of men who have sex with men (MSM) in Belo Horizonte, Brazil. In this study, the rate of TDR was evaluated in 64 HIV-infected individuals from a cohort of MSM between 1996-June 2012. Fifty-four percent had a documented recent HIV infection, with a seroconversion time of less than 12 months. The median CD4+T lymphocyte count and VL were 531 cells/mm3 and 17,746 copies/mL, respectively. Considering the surveillance drug resistance mutation criteria, nine (14.1%) patients presented TDR, of which three (4.7%), five (7.8%) and four (6.2%) had protease inhibitors, resistant against nucleos(t)ide transcriptase inhibitors and against non-nucleoside reverse-transcriptase inhibitors mutations, respectively. Two of the patients had multi-drug-resistant HIV-1. The most prevalent viral subtype was B (44, 68.8%), followed by subtype F (11, 17.2%). This study shows that TDR may vary according to the population studied and it may be higher in clusters of MSM.

Transmitted human immunodeficiency virus-1 drug resistance in a cohort of men who have sex with men in Belo Horizonte, Brazil - 1996-2012

The presence of transmitted human immunodeficiency virus (HIV)-1 drug-resistance (TDR) at the time of antiretroviral therapy initiation is associated with failure to achieve viral load (VL) suppression. Here, we report TDR surveillance in a specific population of men who have sex with men (MSM) in Belo Horizonte, Brazil. In this study, the rate of TDR was evaluated in 64 HIV-infected individuals from a cohort of MSM between 1996-June 2012. Fifty-four percent had a documented recent HIV infection, with a seroconversion time of less than 12 months. The median CD4+T lymphocyte count and VL were 531 cells/mm3and 17,746 copies/mL, respectively. Considering the surveillance drug resistance mutation criteria, nine (14.1%) patients presented TDR, of which three (4.7%), five (7.8%) and four (6.2%) had protease inhibitors, resistant against nucleos(t)ide transcriptase inhibitors and against non-nucleoside reverse-transcriptase inhibitors mutations, respectively. Two of the patients had multi-drug-resistant HIV-1. The most prevalent viral subtype was B (44, 68.8%), followed by subtype F (11, 17.2%). This study shows that TDR may vary according to the population studied and it may be higher in clusters of MSM.

HIV Incidence Determination in the United States: A Multiassay Approach

Accurate testing algorithms are needed for estimating human immunodeficiency virus (HIV) incidence from cross-sectional surveys. We developed a multiassay algorithm (MAA) for HIV incidence that includes the BED capture enzyme immunoassay (BED-CEIA), an antibody avidity assay, HIV load, and CD4(+) T-cell count. We analyzed 1782 samples from 709 individuals in the United States who had a known duration of HIV infection (range, 0 to >8 years). Logistic regression with cubic splines was used to compare the performance of the MAA to the BED-CEIA and to determine the window period of the MAA. We compared the annual incidence estimated with the MAA to the annual incidence based on HIV seroconversion in a longitudinal cohort. The MAA had a window period of 141 days (95% confidence interval [CI], 94-150) and a very low false-recent misclassification rate (only 0.4% of 1474 samples from subjects infected for >1 year were misclassified as indicative of recent infection). In a cohort study, annual incidence based on HIV seroconversion was 1.04% (95% CI, .70%-1.55%). The incidence estimate obtained using the MAA was essentially identical: 0.97% (95% CI, .51%-1.71%). The MAA is as sensitive for detecting recent HIV infection as the BED-CEIA and has a very low rate of false-recent misclassification. It provides a powerful tool for cross-sectional HIV incidence determination.

Use of a Multifaceted Approach to Analyze HIV Incidence in a Cohort Study of Women in the United States: HIV Prevention Trials Network 064 Study

Reliable methods for estimating the incidence of human immunodeficiency virus (HIV) infection are needed to monitor the epidemic, identify at-risk populations, and evaluate HIV prevention strategies. We used a multifaceted approach to estimate HIV incidence in the HIV Prevention Trials Network (HPTN) 064 study. The HPTN 064 study enrolled 2067 HIV-seronegative women and 32 HIV-seropositive women with no prior HIV infection diagnosis. Women were followed for up to 12 months. HIV incidence estimates were based on (1) detection of acute HIV infection, (2) documentation of HIV seroconversion, and (3) detection of recent HIV infection, using a multiassay algorithm (MAA). Two women had acute HIV infection at enrollment, 4 seroconverted, and 2 were identified as recently infected at enrollment using the MAA. The annual HIV incidence estimate based on acute infection at enrollment (2.52% [95% confidence interval {CI}, .17%-9.33%], using a 14-day window period) was higher than the estimate based on seroconversion (0.24% [95% CI, .07%-.62%]; P = .027). Incidence estimates obtained using the MAA at enrollment and at the end of study were 0.25% (95% CI, .03%-.93%) and 0.13% (95% CI, .006%-.76%), respectively. We detected a high frequency of acute infection at enrollment. Cross-sectional HIV incidence estimates obtained using the MAA were similar to the longitudinal estimate based on HIV seroconversion. NCT00995176.

Primary resistance of HIV to antiretrovirals among individuals recently diagnosed at voluntary counselling and testing centres in the metropolitan region of Recife, Pernambuco

Determining the prevalence and type of antiretroviral (ARV) resistance among ARV-naïve individuals is important to assess the potential responses of these individuals to first-line regimens. The prevalence of primary resistance and the occurrence of recent infections among individuals with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) were identified among recently diagnosed patients at five sexually transmitted disease/AIDS testing and counselling centres in the metropolitan region of Recife (RMR), Pernambuco, Brazil, between 2007-2009. One-hundred and eight samples were analysed using the Calypte® BED assay. Males predominated (56%), as did patients aged 31-50 years. Twenty-three percent presented evidence of a recent HIV infection. The median CD4+ T lymphocyte count was 408 cells/mm³ and the median viral load was 3.683 copies/mL. The prevalence of primary resistance was 4.6% (confidence interval 95% = 1-8.2%) based on criteria that excluded common polymorphisms in accordance with the surveillance drug resistance mutation criteria. The prevalence of resistance to non-nucleoside reverse transcriptase, nucleoside/nucleotide reverse transcriptase and protease inhibitors were 3.8%, 1.5% and 0.8%, respectively. Fifty-seven percent of strains were from clade B, 37.7% were clade F and 3.1% were clade C; there were no statistically significant differences with respect to resistance between clades. Recent infection tended to be more common in men (p = 0.06) and in municipalities in the south of the RMR (Jaboatão dos Guararapes and Cabo de Santo Agostinho) (p = 0.046). The high prevalence of recent infection and the high prevalence of non-B strains in this poor Brazilian region merit further attention.

Incidence of Recent Human Immunodeficiency Virus Infection at Two Voluntary Counseling Testing Centers in Pernambuco, Brazil, from 2006 to 2009

This study shows HIV-1 incidence in the northeastern region of Brazil, where the HIV epidemic has spread recently. Incidence was higher among men (1.34%; 95% confidence interval [CI], 1.00% to 1.69%) than among women (0.55%; 95% CI, 0.43% to 0.68%) (P < 0.0001), and there was an association between younger age and recent HIV infection (P < 0.004).

Current and future assays for identifying recent HIV infections at the population level

SummaryThe precise diagnosis of recent human immunodeficiency virus (HIV) infection is crucial for estimating HIV incidence, defined as the number of new infections in a population, per person at risk, during a specified time period. Incidence assessment is considered to be a tool for surveillance, public health and research. Differentiating recent from long-term HIV infections is possible thanks to the evaluation of HIV-specific immune response development or viral markers measurement. Several methods that enable the recognition of recent HIV-1 infection with the use of a single blood specimen have been developed, and their value for use in population level studies has been demonstrated. However, they are still inadequate due to a variable window period and false recent rates among HIV clades and across populations. Application of these assays at an individual level is far more questionable because of person-to-person variability in the antibody response and the course of HIV infection, and because of the prospective regulatory approval requirements.In this article we review the principles and the limitations of the currently available major laboratory techniques that allow detection of recent HIV infection. The assays based on the alteration of serological parameters, as well as the newest method based on an increase of HIV genetic diversity with the progress of infection, are described.

Estimating the distribution of the window period for recent HIV infections: A comparison of statistical methods

In the past few years a number of antibody biomarkers have been developed to distinguish between recent and established Human Immunodeficiency Virus (HIV) infection. Typically, a specific threshold/cut-off of the biomarker is chosen, values below which are indicative of recent infections. Such biomarkers have attracted considerable interest as the basis for incidence estimation using a cross-sectional sample. An estimate of HIV incidence can be obtained from the prevalence of recent infection, as measured in the sample, and knowledge of the time spent in the recent infection state, known as the window period. However, such calculations are based on a number of assumptions concerning the distribution of the window period. We compare two statistical methods for estimating the mean and distribution of a window period using data on repeated measurements of an antibody biomarker from a cohort of HIV seroconverters. The methods account for the interval-censored nature of both the date of seroconversion and the date of crossing a specific threshold. We illustrate the methods using repeated measurements of the Avidity Index (AI) and make recommendations about the choice of threshold for this biomarker so that the resulting window period satisfies the assumptions for incidence estimation. Copyright © 2010 John Wiley & Sons, Ltd.

Sensitivity of Five Rapid HIV Tests on Oral Fluid or Finger-Stick Whole Blood: A Real-Time Comparison in a Healthcare Setting

BackgroundHealth authorities in several countries recently recommended the expansion of human immunodeficiency virus (HIV) antibody testing, including the use of rapid tests. Several HIV rapid tests are now licensed in Europe but their sensitivity on total blood and/or oral fluid in routine healthcare settings is not known.Methods and Findings200 adults with documented HIV-1 (n = 194) or HIV-2 infection (n = 6) were prospectively screened with five HIV rapid tests using either oral fluid (OF) or finger-stick whole blood (FSB). The OraQuick Advance rapid HIV1/2® was first applied to OF and then to FSB, while the other tests were applied to FSB, in the following order: Vikia HIV 1/2®, Determine HIV 1–2®, Determine® HIV-1/2 Ag/Ab Combo® and INSTI HIV-1/HIV-2®. Tests negative on FSB were repeated on paired serum samples. Twenty randomly selected HIV-seronegative subjects served as controls, and the results were read blindly. Most patients had HIV-1 subtype B infection (63.3%) and most were on antiretroviral therapy (68.5%). Sensitivity was 86.5%, 94.5%, 98.5%, 94.9%, 95.8% and 99% respectively, with OraQuick OF, OraQuick FSB, Vikia, Determine, Determine Ag/Ab Combo and INSTI (p<0.0001). OraQuick was less sensitive on OF than on FSB (p = 0.008). Among the six patients with three or more negative tests, two had recent HIV infection and four patients on antiretroviral therapy had undetectable plasma viral load. When patients positive in all the tests were compared with patients who had at least one negative test, only a plasma HIV RNA level <200 cp/ml was significantly associated with a false-negative result (p = 0.009). When the 33 rapid tests negative on FSB were repeated on serum, all but six (5 negative with OraQuick, 1 with INSTI) were positive. The sensitivity of OraQuick, Determine and Determine Ag/Ab Combo was significantly better on serum than on FSB (97.5%, p = 0.04; 100%, p = 0.004; and 100%, p = 0.02, respectively).ConclusionWhen evaluated in a healthcare setting, rapid HIV tests were less sensitive on oral fluid than on finger-stick whole blood and less sensitive on finger-stick whole blood than on serum.

Impact of human immunodeficiency virus infection on arterial stiffness and wave reflections in the early disease stages

Background Human immunodeficiency virus (HIV) infection is associated with subclinical inflammation and increased cardiovascular risk. Arterial stiffness and enhanced wave reflections are markers of cardiovascular disease and independent predictors of cardiovascular risk. The effect of HIV infection, per se, on aortic stiffness and wave reflections has not been clearly defined. Methods We studied 51 adults with a recent HIV infection, free of antiretroviral treatment and AIDS diagnosis, as well as 35 controls matched for age, sex and smoking status. Carotid-femoral pulse wave velocity (PWV) and timing of the reflected wave (Tr) were measured as indices of aortic stiffness, while aortic augmentation index (AIx) and augmented pressure (AP) were measured as indices of wave reflections. Results While PWV was similar in the two populations, Tr was significantly lower in HIV-infected subjects compared to controls (by 16.5 ms, p = 0.002). In addition, AIx and AP were decreased (by 6.4%, p = 0.048 and by 3.3 mmHg, p = 0.010, respectively) in subjects with HIV infection. Moreover, HIV-infected patients compared with controls had increased values of hs-CRP [1.37 (0.85–2.53) vs. 0.75 (0.41–1.90) mg/l, p = 0.007] and interleukin-6 [1.90 (0.91–3.9) vs. 1.28 (0.80–2.65) pg/ml, p = 0.048]. Tr was negatively correlated with hs-CRP ( r = −0.283, p = 0.010) and interleukin-6 ( r = −0.278, p = 0.018). Conclusions Our study provides evidence of decreased wave reflections and similar aortic stiffness, as assessed by PWV, in the early stages of HIV infection in treatment-naive patients compared to controls. Subclinical inflammation and resultant peripheral vasodilatation constitute potential mediators of the whole pathophysiological process.

Assessment of the Ability of a Fourth-Generation Immunoassay for Human Immunodeficiency Virus (HIV) Antibody and p24 Antigen To Detect both Acute and Recent HIV Infections in a High-Risk Setting

An immunoassay (IA) that simultaneously detects both antibody to human immunodeficiency virus (HIV) and HIV p24 antigen (Architect HIV Ag/Ab Combo) was evaluated for its ability to detect HIV infection by using a panel of specimens collected from individuals recently infected with HIV type 1 (HIV-1). This IA was found to be capable of detecting the majority (89%) of infections, including 80% of those considered acute infections based on the presence of HIV RNA and the lack of detectable antibody to HIV. Substantial improvements in detection of recent infections by the Architect HIV Ag/Ab Combo relative to previous generations of IAs as well as the capacity to detect acute infections have important implications for HIV prevention strategies.

Implementation of HIV Testing at 2 New York City Bathhouses: From Pilot to Clinical Service

Commercial sex venues (e.g., bathhouses) that cater to men who have sex with men (MSM) continue to function in most urban areas. These venues present a challenge to developing strategies to prevent the spread of the human immunodeficiency virus (HIV), but they also provide opportunities for interventions to reduce the risk and rate of disease transmission. Several cities in the United States have developed programs that offer HIV testing in these venues. Similar programs have not existed before in New York City. A pilot HIV testing program was implemented at 2 New York City bathhouses. Testing included rapid HIV testing, the use of the serologic testing algorithm for recent HIV seroconversion, and pooled plasma HIV viral load to detect and date incident and acute HIV infections. In addition to HIV tests, behavioral and demographic data were collected from 493 presumed HIV-negative participants. The pilot program recruited MSM who were at high risk for HIV infection. Of the 493 men tested, 20 (4%) were found to be positive for HIV, and 8 (40%) of these 20 men demonstrated evidence of acute or recent HIV infection. The program tested men often not tested in more traditional medical settings. Significant disparities were demonstrated in the testing habits of MSM who reported having sex with women and had not disclosed same-sex activities to their caregivers. Bathhouse-based testing for HIV infection can be implemented in New York City and would include a population of MSM who are at high risk for HIV infection. Because of the high rate of recent HIV infection, expanded testing in these venues may be a good strategy to reduce the forward transmission of HIV in this highly sexually active population.

Estimating Incidence of HIV Infection in Uganda

To the Editor: Human immunodeficiency virus (HIV) surveillance is in need of a practical and valid method to measure recent HIV incidence rates and the BED test (a test developed for HIV subtypes B E and D) is increasingly being used for this purpose. However we are greatly concerned over claims of validity given the confusing results this test generates. In their study of risk factors for recent HIV infection in Uganda Dr Mermin and colleagues used this test to estimate incidence in Uganda as 1.8 per 100 personyears at risk (pyar) among 15- to 59-year-olds. The greatest incidence rates were for 35- to 39-year-old women (3.5/ 100 pyar) and 30- to 34-year-old men (2.8/100 pyar). The most recent direct empirical estimate of incidence in Uganda is 0.25 per 100 pyar in 2005 for a rural southwest region with a prevalence level similar to that observed nationally. 3 In these data the age groups with the highest incidence are 10 years younger. The study by Mermin et al points to the agreement between observed incidence in the Rakai cohort (1.7/100 pyar) and the corresponding BED estimate for the region. But although this is an atypically high prevalence area the BED incidence estimate is slightly lower than that for the whole country. To explore their results the authors used a lowerthreshold optical density (OD) to increase specificity at the expense of sensitivity identifying similar risk factors for recent infections. However for both analyses the comparison group included a vast majority of uninfected individuals. Perhaps a more telling analysis would be to compare the risk factors for HIV infections categorized as recent by the BED test with those infected with HIV but not identified as recent infections. Incidence in Uganda may have increased due to changes in risky sexual behavior3 but we would be surprised if it had almost tripled compared with rates that likely existed immediately prior to this study. While we accept the limitations inherent in tracking HIV epidemics through measures of prevalence we are concerned that implausible BEDderived estimates of incidence are being published and that that this could lead to mistaken assessments of the state of the HIV epidemic and trends in risk. (full-text)

Settings for identifying recent HIV infections: the Portuguese experience

Portugal has been the western European country with the highest rate of notified acquired immunodeficiency [corrected] syndrome (AIDS) cases since 1999 and human immunodeficiency virus (HIV) infection cases since 2000. Nonetheless, exact information on the magnitude and trends of recently acquired infections is missing. In a cross-sectional study we aimed to determine HIV prevalence, the proportion of recently acquired infections and the incidence among patients attending a Sexually Transmitted Infections (STI) clinic and among HIV positive cases tested at the AIDS Reference Laboratory (ARL), by using the Avidity Index (AI) of antibodies to identify recent HIV-1 seroconversions. Demographic and behavioural data were collected. At the STI clinic 253 patients were enrolled, 16 were found to be HIV infected (14 HIV-1, 2 HIV-2) and a prevalence of 6.3% was obtained. Four recent HIV-1 infections were identified and the HIV-1 incidence was 3.3% per year. At the ARL, 332 newly diagnosed cases of HIV-1 infection were studied, 59 (17.8%) were recent infections and an annual incidence of 4.1% was estimated. These findings support STI clinics as key sentinel sites for recently acquired HIV infections and illustrate the viability of testing for recent HIV infections in these settings and reinforce the value of this method in the surveillance for better monitoring current trends of the HIV/AIDS epidemic in Portugal.

Risk Factors for Recent HIV Infection in Uganda

Studies of factors associated with acquiring human immunodeficiency virus (HIV) are often based on prevalence data that might not reflect recent infections. To determine demographic, biological, and behavioral factors for recent HIV infection in Uganda. Nationally representative household survey of cross-sectional design conducted in Uganda from August 2004 through January 2005; data were analyzed until November 2007. There were 11,454 women and 9905 men aged 15 to 59 years who were eligible. Questionnaires were completed for 10,826 women (95%) and 8830 men (89%); of those interviewed, blood specimens were collected for 10,227 women (94%) and 8298 men (94%). Specimens seropositive for HIV were tested with the BED IgG capture-based enzyme immunosorbent assay to identify recent seroconversions (median, 155 days) using normalized optical density of 0.8 and adjustments. Of the 1023 HIV infections with BED results, 172 (17%) tested as recent. In multivariate analysis, risk factors associated with recent HIV infection included female sex (adjusted odds ratio [aOR], 2.4; 95% confidence interval [CI], 1.1-5.2); current marital status (widowed vs never married, aOR, 6.1; 95% CI, 2.8-13.3; divorced vs never married, aOR, 3.0; 95% CI, 1.5-6.1); geographic region (north central Uganda vs central Uganda/Kampala, aOR, 2.6; 95% CI, 1.7-4.1); number of sex partners in past year (> or = 2 compared with none; aOR, 2.9; 95% CI, 1.6-5.5); herpes simplex virus type 2 infection (aOR, 3.9; 95% CI, 2.6-5.8); report of a sexually transmitted disease in the past year (aOR, 1.7; 95% CI, 1.2-2.4); and being an uncircumcised man (aOR, 2.5; 95% CI, 1.1-5.3). Among married participants, recent HIV infection was associated with never using condoms with partners outside of marriage (aOR, 3.2; 95% CI, 1.7-6.1) compared with individuals having no outside partners. The risk of incident HIV infection for married individuals who used condoms with at least 1 outside partner was similar to that of those who did not have any partners outside of marriage (aOR, 1.0; 95% CI, 0.3-2.7). A survey of individuals in Uganda who were tested with an HIV assay used to establish recent infection identified risk factors, which offers opportunities for prevention initiatives.

Estimation of HIV Incidence in the United States

Incidence of human immunodeficiency virus (HIV) in the United States has not been directly measured. New assays that differentiate recent vs long-standing HIV infections allow improved estimation of HIV incidence. To estimate HIV incidence in the United States. Remnant diagnostic serum specimens from patients 13 years or older and newly diagnosed with HIV during 2006 in 22 states were tested with the BED HIV-1 capture enzyme immunoassay to classify infections as recent or long-standing. Information on HIV cases was reported to the Centers for Disease Control and Prevention through June 2007. Incidence of HIV in the 22 states during 2006 was estimated using a statistical approach with adjustment for testing frequency and extrapolated to the United States. Results were corroborated with back-calculation of HIV incidence for 1977-2006 based on HIV diagnoses from 40 states and AIDS incidence from 50 states and the District of Columbia. Estimated HIV incidence. An estimated 39,400 persons were diagnosed with HIV in 2006 in the 22 states. Of 6864 diagnostic specimens tested using the BED assay, 2133 (31%) were classified as recent infections. Based on extrapolations from these data, the estimated number of new infections for the United States in 2006 was 56,300 (95% confidence interval [CI], 48,200-64,500); the estimated incidence rate was 22.8 per 100,000 population (95% CI, 19.5-26.1). Forty-five percent of infections were among black individuals and 53% among men who have sex with men. The back-calculation (n = 1.230 million HIV/AIDS cases reported by the end of 2006) yielded an estimate of 55,400 (95% CI, 50,000-60,800) new infections per year for 2003-2006 and indicated that HIV incidence increased in the mid-1990s, then slightly declined after 1999 and has been stable thereafter. This study provides the first direct estimates of HIV incidence in the United States using laboratory technologies previously implemented only in clinic-based settings. New HIV infections in the United States remain concentrated among men who have sex with men and among black individuals.

Cutaneous mastocytosis in human immunodeficiency virus: an unfortunate coincidence?

We report the case of a young man who developed cutaneous mastocytosis on the trunk and limbs after an episode of severe sunburn. He was diagnosed with human immunodeficiency virus (HIV) shortly afterwards. We discuss this interesting and previously unreported temporal relationship between the development of mastocytosis and recent HIV infection, speculating on the potential pathogenetic mechanisms of association.

Accuracy of different thresholds for the anti-HIV avidity index

Surveillance programs for human immunodeficiency virus (HIV) infection are based on the reporting of newly diagnosed cases. In order to guarantee a more accurate estimate of the trends and behaviours of infected people, simple and reliable methods aimed at identifying recent (&lt; 6 months) HIV infections are needed. We evaluated the accuracy of the avidity index (AI) of anti-HIV antibodies on 357 serum samples obtained from 127 subjects for whom an estimated date of seroconversion was calculated on the basis of the interval between the last negative and first positive anti-HIV test result.The ROC curve analysis performed at different thresholds of the AI showed that a cutoff of 0.80 (93.0% sensitivity and 98.5% specificity) yields the best overall accuracy (95.8%) and should be employed for surveillance purposes, whereas the application of the anti-HIV AI on individual cases is not recommended.