Estimating HIV Incidence, Time to Diagnosis, and the Undiagnosed HIV Epidemic Using Routine Surveillance Data.

BACKGROUND Estimates of the size of the undiagnosed HIV-infected population are important to understand the HIV epidemic and to plan interventions, including "test-and-treat" strategies. METHODS We developed a multi-state back-calculation model to estimate HIV incidence, time between infection and diagnosis, and the undiagnosed population by CD4 count strata, using surveillance data on new HIV and AIDS diagnoses. The HIV incidence curve was modelled using cubic splines. The model was tested on simulated data and applied to surveillance data on men who have sex with men in The Netherlands. RESULTS The number of HIV infections could be estimated accurately using simulated data, with most values within the 95% confidence intervals of model predictions. When applying the model to Dutch surveillance data, 15,400 (95% confidence interval [CI] = 15,000, 16,000) men who have sex with men were estimated to have been infected between 1980 and 2011. HIV incidence showed a bimodal distribution, with peaks around 1985 and 2005 and a decline in recent years. Mean time to diagnosis was 6.1 (95% CI = 5.8, 6.4) years between 1984 and 1995 and decreased to 2.6 (2.3, 3.0) years in 2011. By the end of 2011, 11,500 (11,000, 12,000) men who have sex with men in The Netherlands were estimated to be living with HIV, of whom 1,750 (1,450, 2,200) were still undiagnosed. Of the undiagnosed men who have sex with men, 29% (22, 37) were infected for less than 1 year, and 16% (13, 20) for more than 5 years. CONCLUSIONS This multi-state back-calculation model will be useful to estimate HIV incidence, time to diagnosis, and the undiagnosed HIV epidemic based on routine surveillance data.

Evaluation of the city of Houston HIV/STD prevention program in Houston Independent School District (HISD) high schools

This cross-sectional study was undertaken to evaluate the impact in terms of HIV/STD knowledge and sexual behavior that the City of Houston HIV/STD prevention program in HISD high schools has had on students who have participated in it by comparing them with their peers who have not, based on self reports. The study further evaluated the program cost-effectiveness for averting future HIV infections by computing Cost-Utility Ratios based on reported sexual behavior. ^ Mixed results were obtained, indicating a statistically significant difference in knowledge with the intervention group having scored higher (p-value 0.001) but not for any of the behaviors assessed. The knowledge score outcome's overall p-value after adjusting for each stratifying variable (age, grade, gender and ethnicity) was statistically significant. The Odds Ratio of intervention group participants aged 15 years or more scoring 70% or higher was 1.86 times; that of intervention group female participants was 2.29 times; and that of intervention group Black/African American participants was 2.47 times relative to their comparison group counterparts. The knowledge score results remained statistically significant in the logistic regression model, which controlled for age, grade level, gender and ethnicity. The Odds Ratio in this case was 1.74. ^ Three scenarios based on the difference in the risk of HIV infection between the intervention and comparison group were used for computation of Cost-Utility Ratios: Base, worst and best-case scenario. The best-case scenario yielded cost-effective results for male participants and cost-saving results for female participants when using ethnicity-adjusted HIV prevalence. The scenario remained cost-effective for female participants when using the unadjusted HIV prevalence. ^ The challenge to the program is to devise approaches that can enhance benefits for male participants. If it is a threshold problem implying that male participants require more intensive programs for behavioral change, then programs should first be piloted among boys before being implemented across the board. If it is a reflection of gender differences, then we might have to go back to the drawing board and engage boys in focus group discussions that will help formulate more effective programs. Gender-blind approaches currently in vogue do not seem to be working. ^

HIV incidence estimates and HIV/AIDS concurrent diagnosis in Houston/Harris County

The purpose of this dissertation was to estimate HIV incidence among the individuals who had HIV tests performed at the Houston Department of Health and Human Services (HDHHS) public health laboratory, and to examine the prevalence of HIV and AIDS concurrent diagnoses among HIV cases reported between 2000 and 2007 in Houston/Harris County. ^ The first study in this dissertation estimated the cumulative HIV incidence among the individuals testing at Houston public health laboratory using Serologic Testing Algorithms for Recent HIV Seroconversion (STARHS) during the two year study period (June 1, 2005 to May 31, 2007). The HIV incidence was estimated using two independently developed statistical imputation methods, one developed by the Centers for Disease Control and Prevention (CDC), and the other developed by HDHHS. Among the 54,394 persons who tested for HIV during the study period, 942 tested HIV positive (positivity rate=1.7%). Of these HIV positives, 448 (48%) were newly reported to the Houston HIV/AIDS Reporting System (HARS) and 417 of these 448 blood specimens (93%) were available for STARHS testing. The STARHS results showed 139 (33%) out of the 417 specimens were newly infected with HIV. Using both the CDC and HDHHS methods, the estimated cumulative HIV incidences over the two-year study period were similar: 862 per 100,000 persons (95% CI: 655-1,070) by CDC method, and 925 per 100,000 persons (95% CI: 908-943) by HDHHS method. Consistent with the national finding, this study found African Americans, and men who have sex with men (MSM) accounted for most of the new HIV infections among the individuals testing at Houston public health laboratory. Using CDC statistical method, this study also found the highest cumulative HIV incidence (2,176 per 100,000 persons [95%CI: 1,536-2,798]) was among those who tested in the HIV counseling and testing sites, compared to the sexually transmitted disease clinics (1,242 per 100,000 persons [95%CI: 871-1,608]) and city health clinics (215 per 100,000 persons [95%CI: 80-353]. This finding suggested the HIV counseling and testing sites in Houston were successful in reaching high risk populations and testing them early for HIV. In addition, older age groups had higher cumulative HIV incidence, but accounted for smaller proportions of new HIV infections. The incidence in the 30-39 age group (994 per 100,000 persons [95%CI: 625-1,363]) was 1.5 times the incidence in 13-29 age group (645 per 100,000 persons [95%CI: 447-840]); the incidences in 40-49 age group (1,371 per 100,000 persons [95%CI: 765-1,977]) and 50 or above age groups (1,369 per 100,000 persons [95%CI: 318-2,415]) were 2.1 times compared to the youngest 13-29 age group. The increased HIV incidence in older age groups suggested that persons 40 or above were still at risk to contract HIV infections. HIV prevention programs should encourage more people who are age 40 and above to test for HIV. ^ The second study investigated concurrent diagnoses of HIV and AIDS in Houston. Concurrent HIV/AIDS diagnosis is defined as AIDS diagnosis within three months of HIV diagnosis. This study found about one-third of the HIV cases were diagnosed with HIV and AIDS concurrently (within three months) in Houston/Harris County. Using multivariable logistic regression analysis, this study found being male, Hispanic, older, and diagnosed in the private sector of care were positively associated with concurrent HIV and AIDS diagnoses. By contrast, men who had sex with men and also used injection drugs (MSM/IDU) were 0.64 times (95% CI: 0.44-0.93) less likely to have concurrent HIV and AIDS diagnoses. A sensitivity analysis comparing difference durations of elapsed time for concurrent HIV and AIDS diagnosis definitions (1-month, 3-month, and 12-month cut-offs) affected the effect size of the odds ratios, but not the direction. ^ The results of these two studies, one describing characteristics of the individuals who were newly infected with HIV, and the other study describing persons who were diagnosed with HIV and AIDS concurrently, can be used as a reference for HIV prevention program planning in Houston/Harris County. ^

The care to share HIV disclosure study - the attitudes toward and beliefs about HIV disclosure among perinatally-infected HIV-positive youth and their caregivers

HIV incidence has not changed since the introduction of the pandemic. Daily 14,000 persons are infected with HIV and 25 to 50% of the HIV-infected population and subgroups respectively are estimated to be unaware of their HIV diagnosis. Perinatally-infected HIV-positive youth, aged 13-24 years, have survived unexpectedly into adulthood, have had unique HIV disclosure experiences and now face HIV disclosure issues of adulthood and perhaps parenthood. Despite new effective HIV therapies, no HIV prevention plan exists that has diminished the rate of new HIV infections. HIV stigma and lack of universal HIV reporting laws dissuade timely HIV disclosure. Missed HIV disclosure perpetuates HIV transmission and infection. Understanding the attitudes and beliefs of HIV disclosure among perinatally-infected HIV-positive youth and their caregivers may uncover reasons to HIV disclosure delays, avoidance and intentions. The Care to Share HIV Disclosure study was designed to identify the attitudes and beliefs of HIV disclosure among HIV-positve youth (aged 13-24 years), who were infected from birth and who knew their HIV diagnosis, along with their caregivers. Twenty-six participants (15 youth and 11 caregivers) completed the theory-based questionnaires of a 21-item multiple choice survey on HIV disclosure framed in the Theory of Reasoned Action and Theory of Planned Behavior and included an additional open-ended survey that applied the Transactional Model of Stress and Coping to address youth's and caregivers' HIV disclosure experiences. Youth were found to have a selective unfavorable HIV disclosure outcome when among referents of close friends. However youth did believe in HIV partner notification. For caregivers, it mattered who disclosed the HIV illness to the youth. HIV stigma was of concern based on the youths' tendency to believe in keeping HIV a secret and their caregivers' ambivalence to HIV secrecy. However, favorable HIV disclosure outcomes were identified for both youth and caregivers the potential for HIV disclosure: when seeking HIV knowledge, when around caregivers and close family and in situations of perceived controllability as when helping others learn about HIV. These findings unveil HIV disclosure attitudes and beliefs within this population and may reveal the attributes that may inhibit or promote HIV disclosure behaviors. HIV disclosure studies that address attitudes and beliefs among larger populations of youth and HIV-infected persons are necessary to identify effective individual, group and society approaches that would promote timely, responsible and meaningful HIV disclosure methods that promote a healthy identity and interrupt HIV transmission.^

Psychosocial predictors of HIV testing behaviors among high risk heterosexuals

Though a lot of progress has been made in the treatment, prevention, and in increasing the knowledge and awareness of HIV/AIDS, the CDC reports that over 21% of the people infected with HIV are unaware of their HIV serostatus. Thirty-one percent of people infected with HIV are diagnosed late in the disease progression, often too late to prevent the transmission or the progression of HIV to AIDS. CDC has set a goal to increase by the year 2010, the number of people aware of the HIV serostatus by 5%. ^ This study examined the association between decision-making and risk-taking (assessed using the decision-making confidence and risk-taking scales of the Texas Christian University Self Rating Form) and HIV testing behaviors within a population of heterosexuals at risk for HIV infections living in Harris County, Texas (N=923). Data used in the study was obtained during the first cycle of the National HIV Behavioral Surveillance among heterosexuals at risk for HIV infection (NHBS-HET1), conducted from October, 2006 to June, 2007. Eighty percent of the study population reported testing for HIV at some point in their lives. The results showed that individuals who scored high (>3.3) on the decision-making confidence scale of the TCU/SRF were more likely to be tested for HIV when compared to those who scored low on the scale (OR= 2.02, 95% CI= 1.44–2.84), and that individuals who score low on the risk-taking scale of the TCU/SRF were more likely to have been tested for HIV when compared to those who scored high on the scale (OR= 1.65, 95% CI= 1.2–2.31). Several demographic factors were also assessed for their association with HIV testing behaviors. Only sex was found to be associated with HIV testing. ^ The findings suggest that risk-taking and decision-making are predictors of HIV testing behaviors such as prior HIV testing within heterosexuals living in high-risk areas of Houston, Texas, and that intervention designed to improve the risk-taking and decision-making attributes of this population might improve HIV testing within this population.^

HIV prevalence and contextual risk-factors among injection drug users in Harris County, Texas

Injection drug use is the third most frequent risk factor for new HIV infections in the United States. A dual mode of exposure: unsafe drug using practices and risky sexual behaviors underlies injection drug users' (IDUs) risk for HIV infection. This research study aims to characterize patterns of drug use and sexual behaviors and to examine the social contexts associated with risk behaviors among a sample of injection drug users. ^ This cross-sectional study includes 523 eligible injection drug users from Houston, Texas, recruited into the 2009 National HIV Behavioral Surveillance project. Three separate set of analyses were carried out. First, using latent class analysis (LCA) and maximum likelihood we identified classes of behavior describing levels of HIV risk, from nine drug and sexual behaviors. Second, eight separate multivariable regression models were built to examine the odds of reporting a given risk behavior. We constructed the most parsimonious multivariable model using a manual backward stepwise process. Third, we examined whether HIV serostatus knowledge (self-reported positive, negative, or unknown serostatus) is associated with drug use and sexual HIV risk behaviors. ^ Participants were mostly male, older, and non-Hispanic Black. Forty-two percent of our sample had behaviors putting them at high risk, 25% at moderate risk, and 33% at low risk for HIV infection. Individuals in the High-risk group had the highest probability of risky behaviors, categorized as almost always sharing needles (0.93), seldom using condoms (0.10), reporting recent exchange sex partners (0.90), and practicing anal sex (0.34). We observed that unsafe injecting practices were associated with high risk sexual behaviors. IDUs who shared needles had higher odds of having anal sex (OR=2.89, 95%CI: 1.69-4.92) and unprotected sex (OR=2.66, 95%CI: 1.38-5.10) at last sex. Additionally, homelessness was associated with needle sharing (OR=2.24, 95% CI: 1.34-3.76) and cocaine use was associated with multiple sex partners (OR=1.82, 95% CI: 1.07-3.11). Furthermore, twenty-one percent of the sample was unaware of their HIV serostatus. The three groups were not different from each other in terms of drug-use behaviors: always using a new sterile needle, or in sharing needles or drug preparation equipment. However, IDUs unaware of their HIV serostatus were 33% more likely to report having more than three sexual partners in the past 12 months; 45% more likely to report to have unprotected sex and 85% more likely to use drug and or alcohol during or before at last sex compared to HIV-positive IDUs. ^ This analysis underscores the merit of LCA approach to empirically categorize injection drug users into distinct classes and identify their risk pattern using multiple indicators and our results show considerable overlap of high risk sexual and drug use behaviors among the high-risk class members. The observed clustering pattern of drug and sexual risk behavior among this population confirms that injection drug users do not represent a homogeneous population in terms of HIV risk. These findings will help develop tailored prevention programs.^

An inhibitor of HIV-1 protease modulates proteasome activity, antigen presentation, and T cell responses

Inhibitors of the protease of HIV-1 have been used successfully for the treatment of HIV-1-infected patients and AIDS disease. We tested whether these protease inhibitory drugs exerted effects in addition to their antiviral activity. Here, we show in mice infected with lymphocytic choriomeningitis virus and treated with the HIV-1 protease inhibitor ritonavir a marked inhibition of antiviral cytotoxic T lymphocyte (CTL) activity and impaired major histocompatibility complex class I-restricted epitope presentation in the absence of direct effects on lymphocytic choriomeningitis virus replication. A potential molecular target was found: ritonavir selectively inhibited the chymotrypsin-like activity of the 20S proteasome. In view of the possible role of T cell-mediated immunopathology in AIDS pathogenesis, the two mechanisms of action (i.e., reduction of HIV replication and impairment of CTL responses) may complement each other beneficially. Thus, the surprising ability of ritonavir to block the presentation of antigen to CTLs may possibly contribute to therapy of HIV infections but potentially also to the therapy of virally induced immunopathology, autoimmune diseases, and transplantation reactions.

Health care services for persons with human immunodeficiency virus (HIV) infection.

"September 1993."

Global Research Network Meeting on HIV Prevention in Drug-Using Populations : inaugural meeting report, June 25-26, 1998, Geneva, Switzerland /

Shipping list no.: 99-0352-P.

The Public Health Service strategic plan to combat HIV & AIDS in the United States /

Running title: Strategic plan to combat AIDS & HIV in the U.S.

Reading and interpreting the HIV-1 Western Blot test /

Accompanying material in pockets, front and back covers.

Information services for HIV/AIDS : recommendations to the NIH : report of a conference /

"January 1994."