Primary HIV infection--a public health opportunity

A stochastic agent-based model of pathogen propagation in dynamic multi-relational social networks

We describe a general framework for modeling and stochastic simulation of epidemics in realistic dynamic social networks, which incorporates heterogeneity in the types of individuals, types of interconnecting risk-bearing relationships, and types of pathogens transmitted across them. Dynamism is supported through arrival and departure processes, continuous restructuring of risk relationships, and changes to pathogen infectiousness, as mandated by natural history; dynamism is regulated through constraints on the local agency of individual nodes and their risk behaviors, while simulation trajectories are validated using system-wide metrics. To illustrate its utility, we present a case study that applies the proposed framework towards a simulation of HIV in artificial networks of intravenous drug users (IDUs) modeled using data collected in the Social Factors for HIV Risk survey.

The detection and management of early HIV infection: a clinical and public health emergency

This review considers the detection and management of early HIV infection (EHI), defined here as the first 6 months of infection. This phase is clinically important because a reservoir of infected cells formed in the individual renders HIV incurable, and the magnitude of viremia at the end of this period predicts the natural history of disease. Epidemiologically, it is critical because the very high viral load that typically accompanies early infection also makes infected individuals maximally contagious to their sexual partners. Future efforts to prevent HIV transmission with expanded testing and treatment may be compromised by elevated transmission risk earlier in the course of HIV infection, although the extent of this impact is yet unknown. Treatment as prevention efforts will nevertheless need to develop strategies to address testing, linkage to care, and treatment of EHI. Cost-effective and efficient identification of more persons with early HIV will depend on advancements in diagnostic technology and strengthened symptom-based screening strategies. Treatment for persons with EHI must balance individual health benefits and reduction of the risk of onward viral transmission. An increasing body of evidence supports the use of immediate antiretroviral therapy to treat EHI to maintain CD4 count and functionality, limit the size of the HIV reservoir, and reduce the risk of onward viral transmission. Although we can anticipate considerable challenges in identifying and linking to care persons in the earliest phases of HIV infection, there are many reasons to pursue this strategy.

Network Firewall Dynamics and the Subsaturation Stabilization of HIV

In 2001, Friedman et al. conjectured the existence of a "firewall effect" in which individuals who are infected with HIV, but remain in a state of low infectiousness, serve to prevent the virus from spreading. To evaluate this historical conjecture, we develop a new graph-theoretic measure that quantifies the extent to which Friedman's firewall hypothesis(FH)holds in a risk network. We compute this new measure across simulated trajectories of a stochastic discrete dynamical system that models a social network of 25,000 individuals engaging in risk acts over a period of 15 years. The model's parameters are based on analyses of data collected in prior studies of the real-world risk networks of people who inject drugs (PWID) in New York City. Analysis of system trajectories reveals the structural mechanisms by which individuals with mature HIV infections tend to partition the network into homogeneous clusters (with respect to infection status) and how uninfected clusters remain relatively stable (with respect to infection status) over long stretches of time. We confirm the spontaneous emergence of network firewalls in the system and reveal their structural role in the nonspreading of HIV.

Short communication: new HIV infections at Southern New England academic institutions: implications for prevention

New HIV infections among younger men who have sex with men (MSM) in the United States are escalating. Data on HIV infections in college students are limited. In 2010, three MSM college students presented to our clinic with primary HIV infection (PHI) in a single month. To determine the number of college students among new HIV diagnoses, we reviewed clinical characteristics and molecular epidemiology of HIV-diagnosed individuals from January to December 2010 at the largest HIV clinic in Southern New England. PHI was defined as acute HIV infection or seroconversion within the last 6 months. Of 66 individuals diagnosed with HIV in 2010, 62% were MSM and 17% were academic students (12% college or university, 5% other). Seventy-three percent of students were MSM. Compared to nonstudents, students were more likely to be younger (24 versus 39 years), born in the United States (91% versus 56%), have another sexually transmitted disease (45% versus 11%), and present with PHI (73% versus 16%, all p-values<0.05). Thirty percent of individuals formed eight transmission clusters including four students. MSM were more likely to be part of clusters. Department of Health contact tracing of cluster participants allowed further identification of epidemiological linkages. Given these high rates of PHI in recently diagnosed students, institutions of higher education should be aware of acute HIV presentation and the need for rapid diagnosis. Prevention strategies should focus on younger MSM, specifically college-age students who may be at increased risk of HIV infection.

The role of acute and early HIV infection in the spread of HIV and implications for transmission prevention strategies in Lilongwe, Malawi: a modelling study

BACKGROUND

HIV transmission risk is higher during acute and early HIV infection than it is during chronic infection, but the contribution of early infection to the spread of HIV is controversial. We estimated the contribution of early infection to HIV incidence in Lilongwe, Malawi, and predict the future effect of hypothetical prevention interventions targeted at early infection only, chronic infection only, or both stages.

METHODS

We developed a deterministic mathematical model describing heterosexual HIV transmission, informed by detailed behavioural and viral-load data collected in Lilongwe. We included sexual contact within and outside of steady pairs and divided the infectious period into intervals to allow for changes in transmissibility by infection stage. We used a Bayesian melding approach to fit the model to HIV prevalence data collected between 1987 and 2005 at Lilongwe antenatal clinics. We assessed interventions that reduced the per-contact transmission probability to 0.00003 in people receiving them, and varied the proportion of individuals receiving the intervention in each stage.

FINDINGS

We estimated that 38.4% (95% credible interval 18.6-52.3) of HIV transmissions in Lilongwe are attributable to sexual contact with individuals with early infection. Interventions targeted at only early infection substantially reduced HIV prevalence, but did not lead to elimination, even with 100% coverage. Interventions targeted at only chronic infections also reduced HIV prevalence, but coverage levels of 95-99% were needed for the elimination of HIV. In scenarios with less than 95% coverage of interventions targeted at chronic infections, additional interventions reaching 25-75% of individuals with early infection reduced HIV prevalence substantially.

INTERPRETATION

Our results suggest that early infection plays an important part in HIV transmission in this sub-Saharan African setting. Without near-complete coverage, interventions during chronic infection will probably have incomplete effectiveness unless complemented by strategies targeting individuals with early HIV infection.

FUNDING

National Institutes of Health, University of North Carolina Center for AIDS Research.

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.

Identifying people with acute HIV infection: demographic features, risk factors, and use of health care among individuals with AHI in North Carolina

Identifying and counseling individuals with Acute HIV Infection (AHI) offers a critical opportunity to avert preventable HIV transmission, however, opportunities to recognize these individuals may be missed. We surveyed 32 adults diagnosed with AHI during voluntary HIV testing from 1/1/03 to 2/28/05 in publicly funded testing sites in NC to describe their clinical, social, and behavioral characteristics. Eighty-one percent of participants were men; 59% were African American. Seventy-five percent experienced symptoms consistent with acute retroviral syndrome; although 83% sought medical care for these symptoms, only 15% were appropriately diagnosed at that initial medical visit, suggesting opportunities to diagnose these individuals earlier were missed. Eighty-five percent of the men engaged in sex with men. More than 50% of the participants thought they were infected with HIV by a steady partner. This study yields important information to assist in identifying populations at risk for or infected with AHI and designing both primary and secondary prevention interventions.

Behavior change following diagnosis with acute/early HIV infection-a move to serosorting with other HIV-infected individuals. The NIMH Multisite Acute HIV Infection Study: III

Risk reductions behaviors are especially important during acute/early HIV infection, a period of high transmission risk. We examined how sexual behaviors changed following diagnosis of acute/early HIV infection. Twenty-eight individuals completed structured surveys and in-depth interviews shortly after learning of their infection and 2 months later. Quantitative analyses revealed significant changes after diagnosis, including reductions in total partners and decreases in the proportion of unprotected sex acts occurring with uninfected partners (serosorting). Qualitative findings indicated that these changes were motivated by concerns about infecting others. However, participants were less successful at increasing the frequency with which they used condoms. These results suggest that the initial diagnosis with HIV may constitute an important component of interventions to promote risk reduction during the acute/early stages of the disease.

High HIV and ulcerative sexually transmitted infection incidence estimates among men who have sex with men in Peru: awaiting for an effective preventive intervention

BACKGROUND

In the Andean Region, HIV and sexually transmitted infections (STI) are most prevalent among men who have sex with men (MSM), but incidence estimates and associated factors have never been prospectively assessed.

METHODS

A cohort of 1,056 high-risk HIV-negative MSM in Lima, Peru, were recruited during 1998-2000 (the ALASKA Cohort), and a nested case-control analysis was conducted between seroconverters and nonseroconverters, matched 1:3 by age and duration of follow-up for comparison of risk behaviors, acute retroviral symptoms, circumcision, and STI.

RESULTS

During average follow-up of 335 days, 34 men seroconverted, providing a HIV incidence estimate of 3.5 per 100 person-years [95% confidence interval (CI): 2.3 to 4.7]. High syphilis (8.4 per 100 person-years, 95% CI: 6.7 to 10.1) and herpes simplex virus type 2 (HSV-2) infection (10.4 per 100 person-years, 95% CI: 8.6 to 11.9) incidence estimates were obtained. HIV seroconverters were more likely than men who remained seronegative to report fever >or=3 days (46% vs. 7%), to seek medical care (62% vs. 27%), and to have >or=1 casual partner (86.2% vs. 74.1%) since their last visit. HIV seroconverters also were more likely to have acquired syphilis or HSV-2 infection (31% vs. 8% among initially HSV-2-seronegative men) although they were less likely to be circumcised (4.2% vs. 20.6%, a nonsignificant difference). In multivariate analysis, incident syphilis or HSV-2 infection (odds ratio [OR]: 5.9, 95% CI: 1.5 to 22.7) and sex with any casual partner (OR: 4.8, 95% CI: 0.9 to 26.2) were associated with HIV seroconversion.

CONCLUSIONS

STI that may cause anogenital ulcers are important risk factors for HIV acquisition among high-risk MSM in Lima, a population with a very high HIV incidence estimate. Synergistic interventions focusing in preventing both HIV and HSV-2, like male circumcision, are warranted to be assessed, especially in MSM populations with low levels of circumcision and high incidence estimates of ulcerative STI.

Focusing HIV prevention on those most likely to transmit the virus

Despite some success in reducing HIV incidence, the global epidemic continues to grow. For every person with AIDS in developing countries placed on treatment in 2005, many others were newly infected. We need more effective prevention programs that focus interventions on those most at risk for HIV transmission (MART), particularly those with 1) high behavioral risk and 2) high viral loads due to acute or recent infection, co-infections with other diseases, high viral set points, or untreated AIDS. This article provides examples of how prevention programs can incorporate emerging testing technologies and social/behavioral approaches to reach these individuals, their partners, and the social networks where active transmission is occurring.

How many sexually-acquired HIV infections in the USA are due to acute-phase HIV transmission?

OBJECTIVE

To estimate the number of persons in the USA who acquire HIV as a consequence of risky sexual activities with an acutely-infected sex partner.

METHODS

Estimates of the number of incident infections in the USA that are due to acute-phase HIV transmission were derived from a simple mathematical model that combined epidemiological data with information regarding the relative transmission rates for acutely-infected, nonacutely infected but serostatus-unaware, and serostatus-aware persons living with HIV.

RESULTS

Approximately 2760 (8.6%) of the estimated 32 000 sexually-acquired HIV infections in the USA each year are due to acute-phase transmission of the virus. Multivariate sensitivity analyses with a liberal range of values for key parameters produced an upper bound of 5537 infections, representing 17.3% of the total number of sexually-acquired infections.

CONCLUSIONS

Acute-phase HIV transmission accounts for fewer sexually-acquired infections in the USA than is generally assumed.

HIV testing among young adults in the United States: associations with financial resources and geography

We estimated prevalence and odds ratios for self-reported HIV testing among sexually experienced young adults using nationally representative data obtained from Wave III of the National Longitudinal Study of Adolescent Health (Add Health). The prevalence of testing in the past year was 18.8%. Young adults who had private or no health insurance were less likely to report testing than were young adults who had public health insurance, particularly in the South. Respondents with functional income were less likely to report testing than were those without functional income, particularly in the South and Northeast. Variable HIV testing based on finances and insurance should be addressed.

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.

Prevalence of primary HIV infection in symptomatic ambulatory patients

PURPOSE

Recognizing primary human immunodeficiency virus (HIV) infection is important for public health. The prevalence in outpatient settings is largely unknown but would be useful in developing testing guidelines. The objective of this study is to estimate the national prevalence of primary HIV infection in symptomatic ambulatory patients regardless of risk factors.

METHODS

Patients 13 to 54 years old with each of 17 primary HIV infection symptoms, as well as other reported reasons for their visit consistent with primary HIV infection, were identified from the 2000 National Ambulatory Medical Care and National Hospital Ambulatory Medical Surveys to provide the denominator for the prevalence estimate. These survey data can be extrapolated to represent 90% of all US ambulatory care visits, including those to physician's offices, emergency departments, and hospital clinics. Patients with symptoms and diagnoses inconsistent with a viral illness were excluded. The estimate for the numerator was derived from Centers for Disease Control and Prevention estimates and the medical literature.

RESULTS

Patients complaining of fever and other visit reasons consistent with primary HIV infection had a disease prevalence of 0.66% (0.57%-1.02%), those with rash had a prevalence of 0.50% (0.31%-0.82%), and those with pharyngitis had a prevalence of 0.16% (0.11%-0.22%). Patients with other symptoms represented numbers of visits insufficient for reliable estimates of their prevalence.

CONCLUSIONS

These estimates of the prevalence of primary HIV infection in ambulatory patients with fever, rash, and pharyngitis can aid with development of clinical testing guidelines and clinical decisions around testing for acute HIV infection.

The cost-effectiveness of expanded testing for primary HIV infection

PURPOSE

Primary infection with the human immunodeficiency virus (HIV) is a major factor in the HIV epidemic. Most patients become symptomatic and seek care, but seldom are they tested or is their condition diagnosed. The objectives of this study are to determine whether it is cost-effective to expand testing for primary HIV infection to a larger cohort of patients, and, if so, which diagnostic assay is most cost-effective.

METHODS

We undertook a cost-effectiveness analysis of testing a hypothetical cohort of more than 3 million outpatients with fever and other viral symptoms regardless of HIV risk factors using 3 diagnostic assays: p24 antigen enzyme immunosorbent assay (EIA), HIV-1 RNA assay, and third-generation HIV-1 EIA. Antiretroviral therapy was started when the CD4 cell count decreased to 350/microL. Outcome measures were the incremental cost-effectiveness of the diagnostic assays, number of cases identified, cases avoided in sexual partners, and threshold prevalence. For sensitivity analyses, we used 50,000 dollars as the threshold for cost-effectiveness.

RESULTS

At the baseline prevalence of 0.66%, p24 antigen EIA testing was the most cost-effective option at a cost of 30,800 dollars per quality-adjusted life-year gained when compared with no testing. There were 17,054 cases identified, and infection was avoided in 435 partners. Probabilistic sensitivity analysis, in which the estimates for all variables are varied simultaneously, determined that expanded testing with p24 antigen EIA compared with no testing had a 67% probability of being cost-effective at the baseline prevalence and a 71% probability at a prevalence of 1%.

CONCLUSIONS

Expanded testing for primary HIV infection with p24 antigen EIA may be a sound expenditure of health care resources.

The unexpected movement of the HIV epidemic in the Southeastern United States: transmission among college students

BACKGROUND

Approximately 16 million people are enrolled in institutions of higher learning in the United States. However, college students have not been perceived as at high risk for HIV infection. In early 2003, acute HIV infection was diagnosed in 2 men attending college in North Carolina. We describe an epidemiologic investigation of newly diagnosed HIV infection in men attending college in North Carolina.

METHODS

We reviewed state surveillance records examining new HIV diagnoses in men 18-30 years old between January 1, 2000 and December 31, 2003, living in 69 North Carolina counties. Risk behavior and demographic information for HIV-infected men enrolled in college were compared with HIV-infected male nonenrollees.

RESULTS

Of the 735 records available for review, 84 (11%) were college men. Eighty-seven percent of college men were African American and 92% were men who have sex with men (MSM) or men who have sex with men and women (MSM/W). Compared with noncollege men, college men were more likely to be African American (odds ratio 3.70, 95% CI = 1.86-7.54), to report meeting sex partners at bars or dance clubs (odds ratio 3.01, 95% CI = 1.77-5.10) or on the Internet/chat lines (odds ratio 4.95, 95% CI = 2.53-9.64), or to report use of "ecstasy" or club drugs (odds ratio 4.51, 95% CI = 1.15-15.40). Newly diagnosed HIV infection was found in men in 37 colleges located in North Carolina or surrounding states and a sexual partner network investigation linked 21 colleges, 61 students, and 8 partners of students.

CONCLUSION

We describe an epidemic of HIV infection occurring in North Carolina college students, primarily involving African American MSM and MSM/W. College students represent an at-risk, accessible population, which deserves further HIV prevention interventions.

Transmission of HIV-1 during primary infection: relationship to sexual risk and sexually transmitted infections

OBJECTIVE

To study primary HIV-1 infections (PHI) using molecular and epidemiological approaches in order to assess correlates of transmission in this population.

METHODS

Individuals with PHI were recruited prospectively from a discrete cohort of 1235 individuals under follow-up in a well-defined geographical area between 1999 and 2003. PHI was diagnosed by one of the following: negative HIV antibody test within 18 months, evolving antibody response, or application of the serological testing algorithm for recent HIV seroconversion. The pol gene was sequenced to identify genotypic resistance and facilitate molecular epidemiological analysis. Clinical data were collected and linked in an irretrievable fashion when informed consent was obtained.

RESULTS

A total of 103 individuals with PHI diagnosed between 1999 and 2003 were included in the study; 99 (96%) were male and 90 (91%) were men who have sex with men. Viruses from 35 out of 103 (34%) appeared within 15 phylogenetically related clusters. Significant associations with clustering were: young age, high CD4 cell count, number of sexual contacts, and unprotected anal intercourse (UAI) in the 3 months before diagnosis (P < 0.05 for all). High rates of acute sexually transmitted infections (STI) were observed in both groups with a trend towards higher rates in those individuals with viruses within a cluster (42.9 versus 27.9%; P = 0.13).

CONCLUSION

High rates of partner change, UAI and STI are factors that facilitate onward transmission during PHI. More active identification of individuals during PHI, the management of STI and highly active antiretroviral therapy may all be useful methods to break transmission networks.

Predictors of repeat testing and HIV seroconversion in a sexually transmitted disease clinic population

OBJECTIVE

This study assessed the extent of and characteristics associated with repeat HIV testing in persons presenting to a sexually transmitted disease (STD) clinic.

METHODS

The study population included all 101 newly diagnosed HIV-infected subjects and 411 matched HIV-uninfected subjects identified over a 5-year period in a publicly funded STD clinic in the southeastern United States.

RESULTS

Of the 508 subjects (99%) with available records, 160 (32%) had tested previously. Age, race, return for posttest counseling, and the client's stated reason for coming to the clinic were associated with repeat testing. Among the 160 subjects who had tested previously, self-identifying as a man who has sex with men or having a history of incarceration was strongly associated with HIV seroconversion (adjusted odds ratio [OR], 51.82; 95% confidence interval [CI], 9.10-295.13; adjusted OR, 83.98, 95% CI, 17.26-408.69, respectively). Presenting for STD-related reasons (STD symptoms or requesting an STD check) had a negative association with HIV seroconversion (adjusted OR, 0.07; 95% CI, 0.01-0.90) compared with presenting for the sole purpose of requesting an HIV test.

CONCLUSIONS

Repeat HIV testing is common among patients receiving services at an STD clinic. The role of repeat testing in HIV prevention efforts is complex and poorly understood. Results from this study could be used to identify and target those testing previously at highest risk for contracting HIV for risk-reduction interventions.

Primary human immunodeficiency virus infection presenting as acute pancreatitis

Primary human immunodeficiency virus (HIV) infection can present in a variety of ways. It is important to recognize acute HIV infection, for personal and public health reasons. We present an unusual case of primary HIV infection manifesting as acute pancreatitis.

Frequent detection of acute primary HIV infection in men in Malawi

BACKGROUND

Acute (antibody-negative) HIV infection is associated with high transmission potential but is rarely recognized.

DESIGN

Cross-sectional study.

METHODS

We examined the prevalence and predictors of acute HIV infection among 1361 consecutive male outpatients attending sexually transmitted disease (STD; n = 929) and dermatology (n = 432) clinics in Lilongwe, Malawi. Serum specimens negative for HIV antibodies were screened by HIV RNA PCR using a highly specific pooling/resolution testing algorithm.

RESULTS

Five-hundred and fifty-three men (40.6%) were HIV antibody positive and 24 (1.8%) had acute HIV infection; 23 of 24 acutely infected men were from the STD clinic, where they represented 4.5% of all HIV antibody-negative men and 5.0% of all HIV infections. HIV RNA levels for acutely infected men were significantly higher [median (interquartile range), 6.10 (5.19-6.54) log10 HIV RNA copies/ml] than for 58 HIV antibody-positive men [4.42 (3.91-4.95) log10 copies/ml; P < 0.0001]. The factor most strongly associated with acute HIV infection was STD clinic attendance: (odds ratio, 15.2; 95% confidence interval, 2.04-113.0). In multivariate analysis considering only STD patients, factors associated with acute HIV infection included inguinal adenopathy, genital ulceration and age 24-26 years, the age stratum associated with peak incidence of HIV infection among Malawian men.

CONCLUSIONS

Traditional HIV antibody tests alone are not sufficient to exclude HIV infection among men with acute STD in Malawi due to a surprising proportion of acute HIV infections in this population. Alternative screening methods are required for diagnosis of acute HIV infection; such screening could be important for research and for prevention of the sexual transmission of HIV in select populations.

Acute Human Immunodeficiency Virus Infection in Patients Presenting to an Urban Urgent Care Center

Acute infection with human immunodeficiency virus (HIV) is often accompanied by a flu-like illness, and early identification and treatment may help control the infection and prevent transmission. We enrolled patients who presented to an urban urgent care center with any symptoms of a viral illness and any recent potential risk for HIV infection, and we tested them for acute HIV infection using enzyme-linked immunosorbent and RNA assays. Of 499 patients enrolled over a 1-year period, acute HIV infection was diagnosed in 5 (1.0%; 95% confidence interval [CI], 0.1%-1.9%), and chronic HIV infection was diagnosed in 6 (1.2%; 95% CI, 0.2%-2.2%). There were no false-positive results of the RNA assay. No signs or symptoms reliably distinguished patients with acute HIV infection from those who were HIV uninfected. Given the importance of this diagnosis, testing for acute HIV infection using RNA and antibody assays should be offered to all patients in similar settings with viral symptoms and any risk factors for HIV infection.

Community effects on the risk of HIV infection in rural Tanzania

OBJECTIVES

To investigate the effect of community characteristics on HIV prevalence and incidence.

METHODS

Data from an open cohort study with demographic surveillance, epidemiological surveys, and qualitative research were used to examine the association between individual and community risk factors with HIV prevalence in 1994-5 and incidence between 1994-5 and 1996-7 among men (n=2271) and women (n=2752) living in a rural area in northwest Tanzania. Using subvillages as the unit of analysis, community factors investigated were level of social and economic activity, ratio of bar workers per male population aged 18-59, level of community mobility, and distance to the nearest town. Logistic and Cox regression models were estimated to assess community effects, controlling for multiple individual factors.

RESULTS

All four community factors had strong effects on HIV transmission. Men who lived in subvillages with the highest level of social and economic activity had an odds of being HIV positive that was about five times higher (OR=4.71, 95% CI=2.89 to 6.71) than those in places with low levels of activity; women in these subvillages had an odds that was twice as high (OR=1.92, 95% CI=1.27 to 2.92). After controlling for community effects, the effects of some individual factors on the risk of HIV-education, male circumcision, type of work, and number of household assets-changed notably. The association between HIV incidence and community factors was in the expected direction, but did not reach statistical significance (RR=2.07, p=0.10).

CONCLUSIONS

Results suggest that community characteristics play an important part in the spread of HIV in rural Tanzania. Community effects need both to be considered in individual risk factor analyses and be given more attention in intervention programmes.

Use of laboratory tests and clinical symptoms for identification of primary HIV infection

OBJECTIVE

To determine the sensitivity and specificity of symptoms, three HIV-1 RNA assays, a p24 antigen EIA and a third-generation enzyme immunoassay (EIA) antibody test for diagnosis of primary HIV infection (PHI).

DESIGN

Prospective cohort in a university research program.

PARTICIPANTS

Of 258 eligible persons screened for PHI, 40 had primary/early infection (22 preseroconversion, 18 within 6 months of seroconversion) and 218 did not. Seven participants with preseroconversion HIV-1 from a second center were added for evaluating laboratory tests.

MAIN OUTCOME MEASURE

PHI, defined as a negative or indeterminate antibody test with subsequent conversion. Symptom analysis also included persons with antibody conversion of less than 6 months' duration.

RESULTS

The symptoms most strongly associated with PHI in multivariate analysis were fever [odds ratio (OR) 5.2; 95% confidence interval (CI) 2.3-11.7] and rash (OR 4.8; 95% CI 2.4-9.8). The sensitivity and specificity, respectively, for detecting preseroconversion HIV infection were: p24 antigen, 79% and 99%; third-generation EIA, 79% and 97%; HIV-1 RNA by branched chain DNA 100% and 95%; HIV-1 RNA by polymerase chain reaction 100% and 97%; HIV-1 RNA by transcription-mediated amplification testing, 100% and 98%. False-positive HIV-1 RNA tests were not reproducible and had values < 3000 copies/ml, while only one person with confirmed PHI was in this range.

CONCLUSIONS

Rash and fever indicated the highest risk of PHI. HIV-1 RNA tests are very sensitive for PHI but false-positive results occur. False-positive results can be reduced through duplicate testing and considering tests < 5000 copies/ml as indeterminate results requiring additional testing. p24 antigen was more specific than HIV-1 RNA testing but less sensitive.

Acute seroconversion of HIV infection in the ambulatory care setting

Patients frequently visit ambulatory care settings with acute human immunodeficiency virus (HIV) seroconversion illness, but the illness is often misdiagnosed. This acute viral syndrome, or seroconversion illness, occurs after initial exposure to the HIV virus; it is often resolved before the development of HIV-specific antibodies. Primary HIV infection refers to the 12 months following infection; it includes an acute time period after exposure when routine HIV antibody testing is negative. Primary HIV infection is recognized with the help of a detailed screening history. Diagnosis is confirmed through laboratory tests that detect virus presence. The accurate diagnosis of primary HIV infection can have a beneficial effect on the patient's clinical course and also on public health prevention efforts.

Harm reduction theories and strategies for control of human immunodeficiency virus: a review of the literature

AIM

To provide a comprehensive review of the literature on harm reduction theories and strategies related primarily to licit and illicit drug use.

BACKGROUND

Although human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) disease transmission is well understood, it continues to spread, particularly among injection drug users (IDUs). Despite early indications that HIV would be contained within the IDU community, it is spreading to non-IDU sexual partners and to children of IDUs, threatening a more widespread epidemic.

METHODS

An examination of research studies and theoretical writings including reviews and policy papers published in English between 1990 and 2000.

RESULTS

Harm reduction does not seek to eliminate drug use; it focuses on minimizing the personal and social harms and costs associated with drug use and spread of HIV. It seeks to ameliorate conditions surrounding drug use responsible for the spread of HIV in the IDU community: unequal access to health services; sharing of infected needles; racial and social discrimination; poverty; exposure to street violence; inadequate housing; lack of employment; poor general or mental health and other demographic and social determinants. Some controversial harm reduction strategies are described: methadone maintenance programmes, illegal drugs dispensing under controlled conditions, needle exchanges, HIV testing, vein maintenance, safe-sex and would-care programmes.

CONCLUSION

The main challenge is to get IDUs to protect themselves against HIV when suffering physical and social privations and addiction needs. Diverse perspectives on harm reduction are problematic with consequences for success of drug use initiatives. Practical, ethical and theoretical complexities exist but further research is needed to build support for a harm-reduction orientation in practice and policy formulation.

Comparison of clinical features of acute HIV-1 infection in patients infected sexually or through injection drug use. The Investigators of the Québec Primary HIV Infection Study

Acute HIV-1 infection (AHI) may present with a clinical picture that represents a diagnostic challenge. We tested the hypothesis that two different routes of infection, that is, sexual versus parenteral, might be associated with a difference in the clinical features of AHI. A prospective cohort of seroconvertors was established in Montréal in private medical clinics and hospitals from February 1996 to May 1999. The prevalence of the symptomatic presentation was almost overlapping within the two groups of newly infected individuals 69% (42 of 61) for men having sex with men (MSM) and 69% (18 of 26) for injection drug users (IDUs; p =.98). Comparison of all types of symptoms and signs as well as their duration was also similar in both groups. Of particular interest, the site of lymph node enlargement was not different despite the estimated sites of intravenous inoculation. Oral and anal ulcers were more frequently observed in MSM than in IDUs (6 versus 0 and 4 versus 1, respectively). Neither the mean CD4+ count (514.8 and 414.7 cells/mm3; p =.14) nor the mean viral load (4.45 and 4.70 log copies/ml; p =.40) were different between the two groups at the time of the first study visit. Our study results clearly indicate that health care workers can expect similar clinical presentation of AHI in MSM and in IDUs despite the different routes of infection.

Management of the asymptomatic HIV-infected patient: an update

Guidelines for initiating antiretroviral therapy in asymptomatic patients continue to be debated. Physicians and patients should decide whether drug treatment is advisable after jointly considering psychosocial issues as well as measurements of immune function and HIV burden. Other components of care include appropriate immunizations, screening for other sexually transmitted infections, safer-sex counseling, and referral for substance abuse treatment, if indicated.

Primary human immunodeficiency virus type 1 infection: clinical manifestations among women in Mombasa, Kenya

The occurrence of clinical manifestations associated with primary human immunodeficiency virus type 1 (HIV-1) infection was evaluated in a prospective cohort study of female sex workers in Mombasa, Kenya. Among 103 women who seroconverted to HIV-1, fever, vomiting, diarrhea, headache, arthralgia, myalgia, skin rash, swollen lymph nodes, extrainguinal lymphadenopathy, inguinal lymphadenopathy, and vaginal candidiasis were noted significantly more frequently at visits in which seroconversion first became evident. Eighty-one percent of seroconverting women had >/=1 of these 11 symptoms or signs. Among 44% of the women, the acute illness was severe enough to prevent them from working. Having >/=2 of 6 selected symptoms and signs yielded a sensitivity of 51%, specificity of 83%, positive likelihood ratio of 3.2, and negative likelihood ratio of 0.5 for acute HIV-1 infection. The recognition of primary HIV-1-infection illness in high-risk populations and subsequent risk-reduction counseling could potentially reduce secondary HIV-1 transmission during this highly infectious period.

Diagnostic testing for HIV type 1 RNA in seronegative blood

We studied the feasibility of routine diagnostic testing for HIV-1 RNA at a publicly funded testing site. HIV-1 RNA was determined with a commercial polymerase chain reaction assay in pooled seronegative blood samples submitted for HIV testing to a public health laboratory. Recovery of HIV-1 RNA from the samples was estimated as at least 8% of viral RNA that was found in freshly prepared plasma. We estimated that screening for HIV-1 RNA in serum pools would result in the identification of blood specimens from more than 95% of acutely infected patients. The frequency of HIV-1 RNA in seronegative blood samples was estimated to be between 19 and 601 per 10(6) submitted specimens. The ratio of HIV-1 RNA positive and seronegative samples to specimens with HIV-1 antibodies confirmed by Western blot was estimated to be between 0.2% and 6.6%. The reagent costs for identifying 1 HIV-infected blood sample were 10-fold higher with the commercially available HIV-1 RNA assay compared with the HIV antibody enzyme-linked immunosorbent assay. Diagnostic testing for HIV-1 RNA may be warranted in high-risk populations since acutely infected patients may benefit most from anti-retroviral therapy and are thought to contribute disproportionately to the HIV epidemic.

Epidemiologic evidence for time variation in HIV infectivity

Data from three epidemiologic studies of heterosexual transmission of HIV among monogamous couples are used to assess evidence for time variation in HIV infectivity, possibly related to varying levels of infectiousness following infection in the primary infected partner. Analyses are based on statistical techniques that account for the inherent incompleteness of exposure information from such studies, and that allow direct assessment of the hypotheses that infectivity varies with time since infection and across partnerships. Data include findings from 302 couples from the California Partners' Study and 51 and 31 couples, respectively, from two U.S. Center for Disease Control and Prevention (CDC)-sponsored studies of infection in partners of transfusion recipients. Results indicate weak evidence for higher infectivity following infection of the primary partner, decreasing to relatively lower levels from 2 to 10 years after. Although these findings are consistent with biologic observations of time variation in viral levels, other explanations of the observed pattern (e.g., heterogeneity of infectivity) are equally plausible, pointing out some inherent limitations of data from such studies.