Cost-effectiveness of post-exposure prophylaxis following sexual exposure to HIV:

Post-exposure prophylaxis: an underutilized biomedical HIV prevention method among gay, bisexual and other men who have sex with men in China

Despite abundant evidence on its safety, tolerability and cost-effectiveness, post-exposure prophylaxis (PEP) has not been officially approved for non-occupational use in China. This study aims to assess awareness of, willingness to use, and actual experience with PEP in gay, bisexual and other men who have sex with men (GBM) in China and to explore potential associations between demographic, behavioral, and psychosocial factors and PEP-related outcomes. We recruited a convenience sample through community venue-based strategies, peer referrals, and online advertisement in four cities of China in 2018. We used bivariable and multivariable logistic regression to test associations between potential predictors and PEP outcomes. Over 60% of men reported having heard of PEP prior to the survey, 70% would be willing to use it if exposed to HIV, and 6% reported having used PEP. Awareness of PEP was associated with higher education, more frequent HIV testing, knowing someone who seroconverted in the past two years, having sex with only men in the past six months, and lower perceived risk of HIV infection. PEP willingness was associated with more frequent HIV testing, being worried about becoming HIV infected, prior awareness and favorable attitudes towards PEP among friends. Findings suggest PEP is an underutilized diomedical HIV prevention intervention among GBM in China. Clinical guidance on non-occupational PEP use, as well as communication campaigns targeting social networks of GBM are needed to address barriers to PEP awareness and uptake.

To prescribe, or not to prescribe: decision making in HIV-1 post-exposure prophylaxis

OBJECTIVES

We investigated the trend in usage of post-exposure prophylaxis (PEP) after HIV-1 risk exposure and evaluated PEP prescription decision making of physicians according to guidelines.

METHODS

All PEP consultations from January 2014 to December 2016 in patients presenting at the University Hospital of Cologne (Germany) were retrospectively analysed. HIV risk contacts included sexual and occupational exposure. The European AIDS Clinical Society (EACS) Guidelines for HIV PEP (version 9.0, 2017) were used for assessment.

RESULTS

A total of 649 patients presented at the emergency department (ED) or the clinic for infectious diseases (IDC) for PEP consultations. A continuous increase in the number of PEP requests was recorded: 189 in 2014, 208 in 2015 and 252 in 2016. PEP consultations in men who have sex with men (MSM) showed a remarkable increase in 2016 (2014, n = 96; 2015, n = 101; 2016, n = 152). Decisions taken by physicians with a specialization in infectious diseases (n = 547) included 61 (11%) guideline-discordant prescriptions [2014: 14% (n = 22); 2015: 9% (n = 16); 2016: 11% (n = 23)]. Among these, sexual exposure accounted for 45 (74%) cases, including 15 cases of nonconsensual sex, while occupational exposure accounted for 14 (23%) cases and other exposure two cases (3%). The main reason for guideline-discordant PEP prescriptions was emotional stress of the patient (n = 37/61).

CONCLUSIONS

PEP prescriptions are increasing and decision making is influenced by patients' emotional stress, but PEP prescriptions should be strictly administered according to risk assessment.

Pre-Exposure Chemoprophylaxis (PREP) as an HIV Prevention Strategy

Chemoprophylaxis may be a prevention strategy for the sexual transmission of human immunodeficiency virus (HIV). Evidence suggests that condom use has waned with the availability of antiretroviral medication, at least in some resource-rich settings. Barrier methods of HIV prevention have inherent problems, and the potential for failure. Microbicide research has focused primarily on male-to-female transmission. Analogous to post-exposure prophylaxis, HIV prevention may be achieved by pre-exposure prophylaxis in some settings. Research in this potential strategy may be rewarding.

HIV medical providers' perceptions of the use of antiretroviral therapy as nonoccupational postexposure prophylaxis in 2 major metropolitan areas

INTRODUCTION

In 2005, the Centers for Disease Control and Prevention expanded its recommendation of postexposure prophylaxis (PEP) use in the workplace to include nonoccupational exposures (nPEP). The availability and extensive use of nPEP have not achieved widespread acceptance among health-care providers of high-risk populations, and public health and primary care agencies have been sparse in their implementation of nPEP promotion, protocols, and practices.

METHODS

We conducted a survey of HIV providers (n = 142, response rate = 61%) in Miami-Dade County (Florida) and the District of Columbia that focused on their knowledge, attitudes, beliefs, and practices related to the delivery of nPEP. We then analyzed differences in survey responses by site and by history of prescribing nPEP using bivariate and multivariate logistic regression.

RESULTS

More District of Columbia providers (59.7%) reported ever prescribing nPEP than in Miami (39.5%, P < 0.048). The majority of practices in both cities did not have a written nPEP protocol and rarely or never had patients request nPEP. Multivariable analysis for history of prescribing nPEP was dominated by having patients request nPEP [odds ratio (OR) = 21.53] and the belief that nPEP would lead to antiretroviral resistance (OR = 0.14) and having a written nPEP protocol (OR = 7.49).

DISCUSSION

Our findings are consistent with earlier studies showing the underuse of nPEP as a prevention strategy. The significance of having a written nPEP protocol and of patient requests for nPEP speaks to the importance of using targeted strategies to promote widespread awareness of the use of HIV antiretroviral medications as a prevention intervention.

Condom distribution in jail to prevent HIV infection

To determine if a structural intervention of providing one condom a week to inmates in the Los Angeles County Men’s Central Jail MSM unit reduces HIV transmissions and net social cost, we estimated numbers of new HIV infections (1) when condoms are available; and (2) when they are not. Input data came from a 2007 survey of inmates, the literature and intervention program records. Base case estimates showed that condom distribution averted 1/4 of HIV transmissions. We predict .8 new infections monthly among 69 HIV-negative, sexually active inmates without condom distribution, but .6 new infections with condom availability. The discounted future medical costs averted due to fewer HIV transmissions exceed program costs, so condom distribution in jail reduces total costs. Cost savings were sensitive to the proportion of anal sex acts protected by condoms, thus allowing inmates more than one condom per week could potentially increase the program’s effectiveness.

Phylodynamic and phylogeographic patterns of the HIV type 1 subtype F1 parenteral epidemic in Romania

In the late 1980s an HIV-1 epidemic emerged in Romania that was dominated by subtype F1. The main route of infection is believed to be parenteral transmission in children. We sequenced partial pol coding regions of 70 subtype F1 samples from children and adolescents from the PENTA-EPPICC network of which 67 were from Romania. Phylogenetic reconstruction using the sequences and other publically available global subtype F sequences showed that 79% of Romanian F1 sequences formed a statistically robust monophyletic cluster. The monophyletic cluster was epidemiologically linked to parenteral transmission in children. Coalescent-based analysis dated the origins of the parenteral epidemic to 1983 [1981-1987; 95% HPD]. The analysis also shows that the epidemic's effective population size has remained fairly constant since the early 1990s suggesting limited onward spread of the virus within the population. Furthermore, phylogeographic analysis suggests that the root location of the parenteral epidemic was Bucharest.

Paying for prevention: challenges to health insurance coverage for biomedical HIV prevention in the United States

Reducing the incidence of HIV infection continues to be a crucial public health priority in the United States, especially among populations at elevated risk such as men who have sex with men, transgender women, people who inject drugs, and racial and ethnic minority communities. Although most HIV prevention efforts to date have focused on changing risky behaviors, the past decade yielded efficacious new biomedical technologies designed to prevent infection, such as the prophylactic use of antiretroviral drugs and the first indications of an efficacious vaccine. Access to prevention technologies will be a significant part of the next decade's response to HIV and advocates are mobilizing to achieve more widespread use of these interventions. These breakthroughs, however, arrive at a time of escalating healthcare costs; health insurance coverage therefore raises pressing new questions about priority-setting and the allocation of responsibility for public health. The goals of this Article are to identify legal challenges and potential solutions for expanding access to biomedical HIV prevention through health insurance coverage. This Article discusses the public policy implications of HIVprevention coverage decisions, assesses possible legal grounds on which insurers may initially deny coverage for these technologies, and evaluates the extent to which these denials may survive external and judicial review. Because several of these legal grounds may be persuasive, particularly denials on the basis of medical necessity, this Article also explores alternative strategies for financing biomedical HIV prevention efforts.

HIV seroconversions among male non-occupational post-exposure prophylaxis service users: a data linkage study

BACKGROUND

Despite widespread prescription of non-occupational post-exposure prophylaxis (NPEP) in Victoria, little is known about subsequent HIV acquisition among NPEP users. We linked the Victorian NPEP Service (VNPEPS) database and the Victorian HIV Surveillance Registry to determine the number, incidence rate and predictive factors of HIV seroconversions among users of the VNPEPS.

METHODS

Records from male patients that received NPEP in the VNPEPS database (n = 1420) between January 2001 and February 2008 were linked with all entries in the Victorian HIV Surveillance Registry up to May 2008.

RESULTS

Sixty-one men who presented to the VNPEPS were identified as HIV seropositive; 16 of these were diagnosed at initial presentation for NPEP. The incidence of HIV seroconversion in males who were HIV seronegative at first presentation for NPEP was 1.27 (95% confidence interval 0.95-1.70) per 100 person-years. There was no association between HIV seroconversion and number of NPEP presentations or age. The median age of seroconversion was 34.6 years.

CONCLUSION

The incidence of HIV infection among men presenting to the VNPEPS is slightly lower than the HIV incidence in NPEP users in a recent Australian cohort study of men who have sex with men, but higher than HIV incidence in general gay male populations. Frequency of NPEP use was not associated with risk of HIV seroconversion. Examination of risk behaviour before and after NPEP use in this population is required to further assess the impact of NPEP availability and use on HIV incidence rates and risk behaviour in Australia.

What do mathematical models tell us about the emergence and spread of drug-resistant HIV?

PURPOSE OF REVIEW

To discuss recent HIV epidemic models examining the transmission of antiretroviral (ARV) drug resistance.

RECENT FINDINGS

A relatively small number of recent transmission models have investigated ARV resistance in the context of therapeutic, combined ART (cART); ARV-vaginal microbicides (ARV-VMB); and oral pre-exposure prophylaxis (PrEP). Models of cART use have highlighted potential concerns about future resistance transmission, particularly in resource-constrained settings, and have emphasized the benefits of viral load monitoring in limiting resistance spread. PrEP models have concluded that inadvertent use by HIV-infected individuals could increase resistance prevalence, and that risk compensation by PrEP users could limit their beneficial effects on HIV transmission. ARV-VMB models have demonstrated that whereas resistance can reduce prophylactic effectiveness in preventing HIV acquisition of female ARV-VMB users, it may concomitantly benefit users' male partners if the resistant strains that female users acquire are less transmissible than wild-type strains. The models have examined the balance between these two factors at the population level.

SUMMARY

Recent HIV transmission models have adopted a wide assortment of structures and assumptions to explore drug resistance in the context of different ARV interventions in various settings. There is a need for future work emphasizing the simultaneous effects of multiple ARV interventions, as well as the public health impact of resistance, not just its prevalence.

Postexposure prophylaxis, preexposure prophylaxis or universal test and treat: the strategic use of antiretroviral drugs to prevent HIV acquisition and transmission

This review considers the use of antiretroviral drugs specifically to prevent HIV transmission. Antiretroviral therapy (ART) can be implemented for the protection of uninfected individuals both before (preexposure prophylaxis) and after (postexposure prophylaxis) exposure to HIV infection. Preexposure prophylaxis may be used coitally dependently when individuals are intermittently exposed or by continuous daily dosing for those constantly exposed; postexposure prophylaxis is used in 28-day courses. Alternatively, ART can be used strategically to reduce the viral load and consequent infectiousness of an HIV-infected individual, thereby limiting the risk of onward viral transmission. A policy of universal HIV testing to enhance the identification of all HIV-positive individuals followed by immediate treatment of all HIV-positive individuals, irrespective of their CD4 cell counts (universal test and treat), has been postulated as a potential tool capable of reducing HIV incidence at a population level. This concept represents a paradigm shift in the use of ART, targeting infectious individuals for prevention rather than protecting uninfected exposed populations. This strategy could have the advantage of preventing transmission and reducing HIV incidence at a population level, as well as delivering universal access to therapy for all people living with HIV and AIDS, potentially eliminating mother-to-child HIV transmission and limiting concomitant diseases such as tuberculosis. This review critically examines the scientific basis of ART for HIV prevention, summarizing the risks and opportunities of the potential expansion of ART for prevention. Specifically, we consider the evidences for and against targeting HIV-uninfected individuals compared with enhanced HIV testing and treatment of HIV-infected individuals in terms of impact on viral transmission.

Genetic subtypes of HIV type 1 circulating in Slovakia

Slovakia belongs to the group of European countries with a low prevalence of HIV infection. The major proportion of HIV-positive cases in Slovakia is still represented by MSM, followed by heterosexuals infected through unprotected sexual intercourse. This study was conducted to update the description of HIV subtypes circulating in Slovakia. HIV-1 partial pol gene sequences from 143 individuals were prospectively collected from 2004 to 2008 and analyzed. Phylogenetic analysis based on HIV-1 partial pol gene sequences revealed the highest prevalence of HIV-1 B subtype (93.0 %), predominantly associated with the MSM group. Ten (7.0%) individuals were infected with HIV-1 non-B subtypes. The pure subtypes were more frequent (7; 4.9%) than CRFs (3; 2.1%) and their occurrence was as follows: subtype C (3; 2, 1%), subtype A (2; 1.4%), subtype F (2; 1.4%), CRF_01AE (1; 0.7%), CRF_02AG (1; 0.7%), and CRF08_BC (1; 0.7%). Data show slightly increasing HIV-1 subtype diversity, with HIV-1 subtype B still having the highest prevalence in the Slovak-infected population.

The Danish PEP registry: experience with the use of postexposure prophylaxis (PEP) following sexual exposure to HIV from 1998 to 2006

BACKGROUND

Studies indicate that antiretroviral postexposure prophylaxis (PEP) after sexual exposure to HIV reduce the risk of infection considerably. Since 1998 PEP after sexual HIV exposure within the preceding 24 hours, has been available in Denmark. PEP can only be prescribed at clinical centers with specialists experienced in HIV treatment. The objective of this study is to describe the use of PEP after sexual exposure from 1998 to 2006.

METHODS

The Danish PEP registry collects data from all cases of PEP use in Denmark after exposure to HIV through a structured questionnaire.

RESULTS

There were 374 cases of PEP use after sexual exposure. The incidence increased from 5 cases in 1997 to 87 in 2006. PEP was used by heterosexuals (40%) as well as men who have sex with men (57%). The HIV-status of the source was unknown in 41% of the cases of which 90% involved a source belonging to a high risk group, and 63% involved exposure by receptive anal intercourse. PEP was administered within 24 hours in 95% of the cases and the median time to initiation (N = 225) was 11.0 hours (range 0.5-60.0). PEP was completed by 65%.

CONCLUSIONS

This nationwide study showed a steady but moderate increase in the use of PEP after sexual HIV-exposure from 1998 to 2006. Time to initiation of PEP was low and the PEP prescription practice was targeted toward high risk exposures.

Sexual risk behaviors among men who have sex with men using erectile dysfunction medications

This study examined relationships between use of the phosphodiesterase type-5 (PDE-5) inhibitors (erectile dysfunction medications) sildenafil (Viagra), Pfizer, New York, NY), tadalafil (Cialis), Eli Lily, Indianapolis, IN), and/or vardenafil (Levitra), Bayer, Berlin, Germany), substance use, perceptions of risk, and sexual behavior in men who have sex with men (MSM). MSM (N = 342) attending a gay pride festival completed a brief survey assessing sexual behavior, risk perceptions, and substance use, including the use and the source of PDE-5 inhibitors. More than a quarter of the sample (26.3%, n = 89) reported having ever used a PDE-5 inhibitor. Those reporting use of PDE-5 inhibitors had higher rates of sexual risk behaviors and differed in their assessment of the risk of HIV transmission for unprotected anal sex. Users who received PDE-5 inhibitors from their doctors did not report sexual behaviors that differed significantly from those who received PDE-5 inhibitors from nonphysician sources. In a sequential logistic regression analysis, recent PDE-5 inhibitor use was associated with unprotected anal sex after accounting for the influence of age, education, ethnic identity, and substance use. Many MSM users of erectile dysfunction drugs report behaviors that may place their and others' health at risk. Interventions to reduce risk among MSM PDE-5 inhibitor users should be explored.

High HIV Type 1 prevalence and wide genetic diversity with dominance of recombinant strains but low level of antiretroviral drug-resistance mutations in untreated patients in northeast Gabon, Central Africa

The northeast of Gabon, central Africa is characterized by high population density and a high rate of immigration from the surrounding countries. To determine the prevalence, circulating subtypes, and antiretroviral resistance mutations of HIV-1, 810 blood samples were collected from the general population of the two main cities (Oyem and Makokou) of this region. Of these, 61 (7.5%) were found to be positive for HIV-1. Analysis of the env (gp120), pol, and gag (p24) sequences as well as phylogenetic analyses showed at least eight different viral lineages. The most prevalent strains were CRF02 recombinants, followed by subtypes A, D, and C. The remaining strains were found to be F, J, G, and also, for the first time in Gabon, the recombinant form CRF11cpx. Analysis of antiretroviral drug-resistance mutations in protease and reverse transcriptase from this untreated population showed a low level of specific mutations. These mutations were associated with subtype polymorphism rather than with resistance to antiretroviral drugs. The wide diversity and the emergence of recombinant strains are in accordance with the rapid spread of new HIV strains in the population and, thus, the dynamic evolution of the epidemic.

Non-B HIV type 1 subtypes among men who have sex with men in Rome, Italy

An increase in the circulation of HIV-1 non-B subtypes has been observed in recent years in Western European countries. Due to the lack of data on the circulation of HIV-1 non-B subtypes among European HIV-1-infected men who have sex with men (MSM), a biomolecular study was conducted in Rome, Italy. HIV-1 partial pol gene sequences from 111 MSM individuals (76 drug naive and 35 drug experienced) were collected during the years 2004-2006. All these sequences were analyzed using the REGA HIV-1 Subtyping Tool, and aligned using CLUSTAL X followed by manual editing using the Bioedit software. A BLAST search for non-B subtype sequences was also performed. Twenty-six (23.4%) MSM were not Italians. Eight individuals (7.2%) were diagnosed as HIV infected before 1991, 20 (18.0%) between 1991 and 1999, and 83 (74.8%) from 2000 to 2006. Fifteen (15/111, 13.5%) individuals were infected with the non-B subtype. The percentage of infection with HIV-1 non-B subtypes was 8.2% (7/85) among Italian MSM and 30.8% (8/26) among the non-Italians (OR = 4.95 95% IC: 1.40-17.87). Individuals infected with the non-B subtype were significantly younger than those infected with the HIV-1 B subtype (28 years vs. 34 years, p = 0.003). The CRFs were more prevalent (8.1%) than pure subtypes (5.4%), which were distributed as follows: subtype C (2.6%), subtype A1 (1.7%), and subtype F1 (0.9%). Major mutations conferring resistance to antiretroviral drugs (ARV) were not found among HIV-1 non-B subtype drug-naive patients but were found in two ARV-experienced individuals. The data show that viral diversity is likely increasing in a population group that had been previously characterized by the circulation of HIV-1 subtype B.

Prospective cohort study of HIV post-exposure prophylaxis for sexual assault survivors

BACKGROUND

There is a lack of standardized programs for HIV counselling and post-exposure prophylaxis (PEP) in the setting of sexual assault.

METHODS

We conducted an 18-month prospective cohort study assessing universal HIV counselling for all sexual assault survivors presenting to 18 Ontario Sexual Assault Treatment Centres. HIV PEP was universally offered to those at risk of HIV infection (high risk or unknown risk) presenting < or =72 h after the assault, using Combivir one pill and Kaletra three capsules twice a day for 28 days. Those who accepted HIV PEP were monitored via a schedule of frequent follow ups. The primary outcomes were acceptance and completion rates, and their predictors were determined using multivariable logistic regression. Adverse events (AE) were categorized using a standardized toxicity grading system.

RESULTS

Of the 900 evaluable participants eligible for PEP, 798 (69 at high risk and 729 at unknown risk) were offered treatment. Acceptance rates were 66.7% (n=46) and 41.3% (n=301) for participants at high risk and unknown risk, respectively. Participants at high risk were 2.2 times more likely to accept PEP than those at unknown risk (adjusted odds ratio 2.2; 95% confidence interval 1.2-4.0; P=0.01). Overall, 23.9% high-risk (n=11) and 33.2% unknown-risk participants (n=100) completed PEP (P=0.20). Predictors of acceptance and completion included assault by a stranger and participant anxiety. AEs were common, with 77.1% of participants reporting grade 2-4 symptoms.

CONCLUSION

A province-wide standardized program of universal HIV counselling and offering of PEP to sexual assault survivors with frequent follow up was successfully implemented and feasible.

A Systematic Review of Cost-Utility Analyses in HIV/AIDS: Implications for Public Policy

Objectives . To determine whether gaps exist in published cost-utility analyses as measured by their coverage of topics addressed in current HIV guidelines from the Department of Health and Human Services (DHHS). Design . A systematic review of US-based cost-effectiveness analyses of HIV/AIDS prevention and management strategies, based on original, published research. Methods . Predefined criteria were used to identify all analyses pertaining to prevention and management of HIV/AIDS; information was collected on type of strategy, patient demographics, study perspective, quality of the study, effectiveness measures, costs, and cost-effectiveness ratios. Results . One hundred and six studies were identified; 62 described strategies for averting new HIV infections, and 44 dealt with managing persons who are HIV positive. The quality of studies was generally high, but gaps were found in all studies. Especially common were omissions in reporting data abstraction methodology and discussions of direction and magnitude of potential biases. Among the 22 most highly rated papers (score of 90 or higher), only 1 was cited in the guidelines, and 3 papers reported on interventions that were superseded by newer approaches. Using a $100,000 threshold, the guidelines usually endorsed interventions found to be cost-effective. Exceptions included recommending postexposure prophylaxis (PEP) for populations in which PEP is unlikely to be cost-effective and not recommending primary resistance testing in treatment-naive persons, although the intervention was reported to have a cost-effectiveness ratio of less than $50,000. Conclusions . Despite an abundant literature on the cost-utility of HIV/AIDS-targeted strategies, guidelines cite relatively few of these papers, and gaps exist regarding assessments of some strategies and special populations.

Antiretroviral post-exposure prophylaxis (PEP) for occupational HIV exposure

BACKGROUND

Populations such as healthcare workers (HCWs), injection drug users (IDUs), and people engaging in unprotected sex are all at risk of being infected with the human immunodeficiency virus (HIV). Animal models show that after initial exposure, HIV replicates within dendritic cells of the skin and mucosa before spreading through lymphatic vessels and developing into a systemic infection (CDC 2001). This delay in systemic spread leaves a "window of opportunity" for post-exposure prophylaxis (PEP) using antiretroviral drugs designed to block replication of HIV (CDC 2001). PEP aims to inhibit the replication of the initial inoculum of virus and thereby prevent establishment of chronic HIV infection.

OBJECTIVES

To evaluate the effects of antiretroviral PEP post-occupational exposure to HIV.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, AIDSearch, and the Database of Abstracts of Reviews of Effectiveness were searched from 1985 to January 2005 to identify controlled trials. There were no language restrictions. Because no controlled clinical trials were retrieved, the search was repeated on 31 May 2005 in MEDLINE, AIDSearch and EMBASE using a search strategy to identify analytic observational studies. Handsearches of the reference lists of all pertinent reviews and studies found were also undertaken. Experts in the field of HIV prevention were contacted.

SELECTION CRITERIA

Types of studies: All controlled trials (including randomized clinical trials and controlled clinical trials). If no controlled trials were found, analytic studies (e.g. cohort and case-control studies) were considered. Descriptive studies (i.e. studies with no comparison groups) were excluded. Types of participants included:HCWs exposed to any known or potentially HIV contaminated product;anyone exposed to a needlestick contaminated by known or potentially HIV-infected blood or other bodily fluid in an occupational setting; andanyone exposed through the mucous membranes to an HIV-infected or potentially infected substance in occupational setting.Excluded: Sex workers (PEP post-sexual exposure is addressed in another Cochrane review (Martín 2005)). Types of interventions: Any intervention that administered single or combinations of antiretrovirals as PEP to people exposed to HIV through percutaneous injuries and/or occupational mucous membrane exposures when the HIV status of the source patient was positive or unknown. Studies comparing two types of PEP regimens were considered, as were studies comparing PEP with no intervention. Types of outcome measures:Incidence of HIV infection in those given PEP versus those given placebo or a different PEP regimen; Adherence to PEP; Complications of PEPTypes of outcome measures: Incidence of HIV infection in those given PEP versus those given placebo or a different PEP regimen; Adherence to PEP; Complications of PEP DATA COLLECTION AND ANALYSIS: Data concerning outcomes, details of the interventions, and other study characteristics were extracted by two independent authors (TY and JA) using a standardized data extraction form (Table 04). A third author (GK) resolved disagreements. The following information was gathered from each included study: location of study, date, publication status, demographics (e.g. age, gender, occupation, risk behavior, etc.) of participants/exposure modality, form of PEP used, duration of use, and outcomes. Odds ratios with a 95% confidence interval (CI) were used as the measure of effect. A meta-analysis was performed for adverse events where two-drug regimens were compared with three-drug regimens. Due to overlap between Puro 2000 and Puro 2005, the former was not included in the combined analysis.

MAIN RESULTS

Effect of PEP on HIV seroconversionNo randomized controlled trials were identified. Only one case-control study was included. HIV transmission was significantly associated with deep injury (OR 15, 95% CI 6.0 to 41), visible blood on the device (OR 6.2, 95% CI 2.2 to 21), procedures involving a needle placed in the source patient's blood vessel (OR 4.3, 95% CI 1.7 to 12), and terminal illness in the source patient (OR 5.6, 95% CI 2.0 to 16). After controlling for these risk factors, no differences were detected in the rates at which cases and controls were offered post-exposure prophylaxis with zidovudine. However, cases had significantly lower odds of having taken zidovudine after exposure compared to controls (OR 0.19, 95%CI 0.06 to 0.52). No studies were found that evaluated the effect of two or more antiretroviral drugs for occupational PEP. Adherence to and complications with PEPEight reports from observational comparative studies confirmed findings that adverse events were higher with a three-drug regimen, especially one containing indinavir. However, discontinuation rates were not significantly different.

AUTHORS' CONCLUSIONS

The use of occupational PEP is based on limited direct evidence of effect. However, it is highly unlikely that a definitive placebo-controlled trial will ever be conducted, and, therefore, on the basis of results from a single case-control study, a four-week regimen of PEP should be initiated as soon as possible after exposure, depending on the risk of seroconversion. There is no direct evidence to support the use of multi-drug antiretroviral regimens following occupational exposure to HIV. However, due to the success of combination therapies in treating HIV-infected individuals, a combination of antiretroviral drugs should be used for PEP. Healthcare workers should be counseled about expected adverse events and the strategies for managing these. They should also be advised that PEP is not 100% effective in preventing HIV seroconversion. A randomized controlled clinical trial is neither ethical nor practical. Due to the low risk of HIV seroconversion, a very large sample size would be required to have enough power to show an effect. More rigorous evaluation of adverse events, especially in the developing world, are required. Seeing that current practice is partly based on results from individual primary animal studies, we recommend a formal systematic review of all relevant animal studies.

Model-Based Estimates of HIV Acquisition Due to Prison Rape

Nearly 1.4 million men are incarcerated in federal and state prisons in the United States. These men are disproportionately affected by HIV in comparison with the at-large male population. The elevated prevalence of HIV infection in U.S. prisons has raised concerns over the potential for intraprison HIV transmission due to rape and other forms of sexual victimization. However, the number of men who acquire HIV after being raped in U.S. prisons is not known. We developed a mathematical model of HIV transmission to estimate the likelihood that an incarcerated man would become infected as a result of prison rape and to provide preliminary estimates of the number of prison rape victims who acquire HIV. Our results suggest that between 43 and 93 currently incarcerated men already have or will acquire HIV as a result of being raped in prison.

Cost-effectiveness of HIV post-exposure prophylaxis in France

OBJECTIVE

To assess the cost-effectiveness of HIV post-exposure prophylaxis (PEP) in France.

METHODS

We used a decision tree to evaluate, from a society's perspective, the cost of PEP per quality-adjusted life-year (QALY) saved. We used 1999-2003 PEP surveillance data and literature-derived data on per event transmission probabilities, PEP efficacy and quality of life with HIV. HIV prevalence and lifetime cost of HIV/AIDS management in the HAART era were derived from French studies. We assumed that mean life expectancy in full health was 65 years among uninfected individuals and that the mean survival time after HIV infection was 22.5 years. The costs of PEP drugs and follow-up were derived from the French public sector. A 3% annual rate was used to discount future costs and effects.

RESULTS

During 1999-2003, PEP was prescribed to 8958 individuals (heterosexual sex: 47.6%; homosexual sex: 28.4%; occupational exposure: 23.4%; drug injection: 0.6%); of those, 2143 were exposed to a known HIV-infected source. PEP was estimated to prevent 7.7 infections and saved 64.5 QALY at a net cost of euro 5.7 million, resulting in an overall cost-effectiveness ratio of euro 88,692 per QALY saved. PEP was cost saving for 4.4% of cases and cost effective (< euro 50,000 per QALY) in a further 11.3% of cases. In contrast, 72 and 52% of prescriptions had a cost-effectiveness ratio exceeding euro 200,000 and euro 2 millions, respectively, per QALY saved.

CONCLUSION

Overall, the French PEP programme is only moderately cost effective. PEP guidelines should be revised to target high-risk exposures better.

Sexual risk and HIV acquisition among men who have sex with men travelers to Key West, Florida: a mathematical modeling analysis

The present study investigated the sexual risk behaviors of men who have sex with men (MSM) traveling to a popular gay tourist destination in the United States. In 2004, a brief survey was administered to 247 MSM tourists recruited from gay-oriented venues in Key West, Florida. Data collected included demographics, HIV status, length of stay, substance use, and sexual risk behaviors. A probabilistic model of HIV transmission was used to translate participants' reports of their sexual behaviors while in Key West into estimates of their risk of acquiring HIV. Twenty-two percent of participants reported anal sex with multiple partners over a relatively brief period (M = 4.1 days), and approximately one third reported having sex with a partner met during the vacation period. Modeling analyses suggested that sexual activity among vacationing MSM would account for approximately 201 new HIV infections among MSM visitors to Key West each year. Although previous studies have documented sexual risk behavior in travelers, quantitative estimates of the impact of these behaviors on the spread of HIV are lacking. Findings suggest that the risk-taking behavior of MSM on vacation may play an important role in the dissemination of HIV and other sexually transmitted diseases (STDs). Future research should assess additional factors (e.g., use of highly active antiretroviral therapy) that may affect HIV transmission in MSM travelers. In addition, efforts are needed to develop effective risk-reduction interventions for this population.

Behavioral impact, acceptability, and HIV incidence among homosexual men with access to postexposure chemoprophylaxis for HIV

BACKGROUND

Little is known about the behavioral impact, acceptability, and incidence of HIV infection in persons with easy access to post-sexual exposure prophylaxis (PEP) to prevent HIV.

METHODS

Participants were recruited from a well-characterized, high-risk HIV seronegative homosexual male cohort in Rio de Janeiro, Brazil, given a 4-day supply of zidovudine and lamivudine, and instructed to begin PEP immediately after an eligible exposure. For eligible exposures, an additional 24-day supply was provided. Reported behavior, PEP utilization, adverse events, and incident HIV infection were the main study outcomes. The observed and expected incidences of HIV infection were compared.

RESULTS

Two hundred subjects were enrolled and followed for a median of 24.2 months. The median age was 28 years. PEP was initiated 109 times by 68 participants (34.0%). In comparison to reported behavior at baseline, reported high-risk sexual activities on average declined over time for both PEP and non-PEP users. There were no serious drug-related adverse events. There were 11 HIV seroconversions, 10 among non-PEP users and 1 that was a PEP failure. The overall seroincidence was 2.9 per 100 person-years (95% CI = 1.4, 5.1). The expected number of new HIV infections and corresponding expected seroincidence based on the risk profile were 11.8 and 3.1, respectively (P > 0.97). The most commonly reported reasons for not initiating PEP among seroconverters were sex with a steady partner and not considering the exposure to be of sufficiently high risk to warrant PEP.

CONCLUSION

PEP was safe and did not appear to be associated with increases in reported high-risk behavior in our cohort. Ready access to PEP did not appear to substantially affect HIV transmission, suggesting a limited public health impact of this intervention.

Cost-effectiveness of HIV postexposure prophylaxis following sexual or injection drug exposure in 96 metropolitan areas in the United States

OBJECTIVES

To evaluate the cost-effectiveness of HIV postexposure prophylaxis (PEP) following sexual or injection-related exposures in 96 metropolitan statistical areas in the United States (MSA).

DESIGN

Empirical, model-based cost-effectiveness analysis.

METHODS

Epidemiological and population size estimates from the literature were combined with information about the distribution of exposure types, PEP completion rate, proportion of source partners known to be HIV infected, and PEP program costs obtained from a feasibility study of PEP in San Francisco to estimate the cost-effectiveness of hypothetical PEP programs in each of the 96 MSA. The effectiveness of combination antiretroviral therapy following sexual or drug use-related exposures, which is presently not known, was assumed equal to the effectiveness of zidovudine monotherapy in the occupational setting. The main outcome measure was the cost-utility ratio, defined as the cost per quality-adjusted life year (QALY) saved by the PEP intervention.

RESULTS

The cost-utility ratios for the 96 MSA ranged from 4137 dollars to 39,101 dollars per QALY saved; only two of the ratios exceeded 30,000 dollars per QALY saved. Combined across the 96 MSA, the hypothetical PEP programs would reach nearly 20,000 clients at a total cost of approximately 22 million dollars. The overall cost-utility ratio across MSA was 12,567 dollars per QALY saved. The majority of the HIV infections prevented by PEP were among men and women who reported receptive anal intercourse exposure.

CONCLUSIONS

PEP following sexual or drug use-related exposures could be a cost-effective complement to existing HIV-prevention efforts in most MSA across the United States.

A human bite to the scrotum: a case report and review of the literature

Human bites to the scrotum are rare and can be associated with a high morbidity rate if poorly managed. We report a case of a human bite to the scrotum that was successfully treated with a 5-day course of antibiotics, surgical debridement and healing by secondary intention.

Cost and cost-effectiveness of standard methadone maintenance treatment compared to enriched 180-day methadone detoxification

AIMS

To compare the cost and cost-effectiveness of methadone maintenance treatment and 180-day methadone detoxification enriched with psychosocial services.

DESIGN

Randomized controlled study conducted from May 1995 to April 1999.

SETTING

Research clinic in an established drug treatment program.

PARTICIPANTS

One hundred and seventy-nine adults with diagnosed opioid dependence. Intervention Patients were randomized to methadone maintenance (n = 91), which required monthly 1 hour/week of psychosocial therapy during the first 6 months or 180-day detoxification (n = 88), which required 3 hours/week of psychosocial therapy and 14 education sessions during the first 6 months.

MEASUREMENTS

Total health-care costs and self-reported injection drug use. A two-state Markov model was used to estimate quality-adjusted years of survival. Findings Methadone maintenance produced significantly greater reductions in illicit opioid use than 180-day detoxification during the last 6 months of treatment. Total health-care costs were greater for maintenance than detoxification treatment ($7564 versus $6687; P < 0.001). Although study costs were significantly higher for methadone maintenance than detoxification patients ($4739 versus $2855, P < 0.001), detoxification patients incurred significantly higher costs for substance abuse and mental health care received outside the study. Methadone maintenance may provide a modest survival advantage compared with detoxification. The cost per life-year gained is $16 967. Sensitivity analysis revealed a cost-effectiveness ratio of less than $20 000 per quality-adjusted life-year over a wide range of modeling assumptions.

CONCLUSIONS

Compared with enriched detoxification services, methadone maintenance is more effective than enriched detoxification services with a cost-effectiveness ratio within the range of many accepted medical interventions and may provide a survival advantage. Results provide additional support for the use of sustained methadone therapy as opposed to detoxification for treating opioid addiction.

Knowledge of HIV Postexposure Prophylaxis in a Population of HIV-Positive Outpatients: Results of a French National Survey

Since 1998, French HIV guidelines have recommended use of HIV prophylaxis after unprotected sex (postexposure prophylaxis, or PEP) with an HIV-positive partner. To characterize factors associated with lack of PEP knowledge in an HIV-positive population, a cross-sectional survey was conducted of 737 French HIV-positive outpatients followed in AIDS care units of 2 regions accounting for 60% of French AIDS cases. Information was collected through face-to-face interviews. The sample was weighted to improve national validity. Median age was 41 years, 73.2% of patients were male, and 8.5% reported HIV-related risk behaviors. Those who knew about PEP and those who did not were compared with chi2 tests and logistic regression. One third of the sample had never heard of PEP. In multivariate analysis, lack of PEP knowledge was associated with older age, low educational level, unstable housing, unawareness of current HIV laboratory data, and lack of ability to confide in nurse and to seek out information from various sources. The increased number of people living with HIV infection as a chronic disease raises new challenges for its secondary prevention. Preventive programs aimed at HIV-positive individuals and their sexual partners are strongly needed.

Postexposure prophylaxis in children and adolescents for nonoccupational exposure to human immunodeficiency virus

Exposure to human immunodeficiency virus (HIV) can occur in a number of situations unique to, or more common among, children and adolescents. Guidelines for postexposure prophylaxis (PEP) for occupational and nonoccupational (eg, sexual, needle-sharing) exposures to HIV have been published by the US Public Health Service, but they do not directly address nonoccupational HIV exposures unique to children (such as accidental exposure to human milk from a woman infected with HIV or a puncture wound from a discarded needle on a playground), and they do not provide antiretroviral drug information relevant to PEP in children. This clinical report reviews issues of potential exposure of children and adolescents to HIV and gives recommendations for PEP in those situations. The risk of HIV transmission from nonoccupational, nonperinatal exposure is generally low. Transmission risk is modified by factors related to the source and extent of exposure. Determination of the HIV infection status of the exposure source may not be possible, and data on transmission risk by exposure type may not exist. Except in the setting of perinatal transmission, no studies have demonstrated the safety and efficacy of postexposure use of antiretroviral drugs for the prevention of HIV transmission in nonoccupational settings. Antiretroviral therapy used for PEP is associated with significant toxicity. The decision to initiate prophylaxis needs to be made in consultation with the patient, the family, and a clinician with experience in treatment of persons with HIV infection. If instituted, therapy should be started as soon as possible after an exposure-no later than 72 hours-and continued for 28 days. Many clinicians would use 3 drugs for PEP regimens, although 2 drugs may be considered in certain circumstances. Instruction for avoiding secondary transmission should be given. Careful follow-up is needed for psychologic support, encouragement of medication adherence, toxicity monitoring, and serial HIV antibody testing.

Virological and immunological profiles among patients with undetectable viral load followed prospectively for 24 months

OBJECTIVE

To quantify HIV-RNA in plasma, in lymphoid tissue and proviral DNA in peripheral blood mononuclear cells and to relate these to immunological markers among patients with plasma viral load counts of </= 200 HIV-RNA copies/mL.

METHODS

A prospective study of one hundred and three patients was undertaken with an inclusion criteria of plasma viral load of </= 200 copies/mL. The patients had advanced HIV infection; 25% had developed AIDS. Patients were seen every 6 months for a period of 2 years.

RESULTS

The median plasma viral load was < 20 copies/mL with no increase during follow-up. Thirty-one per cent had plasma viral load of </= 20 copies/mL at all visits, 44% had >/= 1 measurement with 21-200 and 25% had >/= 1 sample with plasma HIV-RNA > 200 copies/mL. Lymphoid tissue viral load was low at enrolment and declined further during follow-up. Baseline HIV-DNA and immunoglobulin (IgA) differed significantly between the plasma viral load rebound groups (P < 0.05).

CONCLUSION

In this cohort, selected solely on the basis of having a plasma viral load of </= 200 copies/mL, we found stable or declining viral loads in the measured compartments during 2 years of follow-up. Baseline HIV-DNA and IgA levels were higher among patients with less complete virological suppression relative to patients with persistently undetectable plasma HIV-RNA. Hence, a high cellular level of HIV-DNA and high plasma IgA may predict subsequent development of low-grade viraemia.

HIV-1 subtypes in Luxembourg, 1983-2000

OBJECTIVES

To study the prevalence of HIV-1 subtypes in Luxembourg between 1983 and 2000. To compare the drug susceptibility of non-B and B clade viruses and the prevalence of resistance-associated mutations and polymorphisms before antiretroviral treatment.

DESIGN

A retrospective study on plasma samples of HIV-infected patients registered at the National Service of Infectious Diseases, Luxembourg, between 1983 and 2000.

METHODS

Genotyping was performed by sequencing of the reverse transcriptase (RT) and protease coding region of the pol gene. Drug susceptibility was assessed in a recombinant virus assay.

RESULTS

A total of 20.1% of the HIV-positive patients were infected with non-B subtypes, and since 1990 the proportion of non-B viruses has increased ninefold. Eleven out of 14 F1 subtypes occurred in patients native to Luxembourg. Major resistance mutations related to protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI) and non-nucleoside reverse transcriptase inhibitors (NNRTI) occurred in less than 3% of treatment-naive viruses; however, 87% of the viruses had at least one PI-associated mutation. Natural polymorphism of the protease and RT coding region was observed more frequently among non-B than B viruses. Significantly more B viruses displayed resistance to the tested PI, NRTI and NNRTI (P = 0.044).

CONCLUSION

The proportion of non-B viruses has increased dramatically since 1990. Non-B subtypes showed no decreased susceptibility to antiretroviral drugs, but displayed minor mutations and polymorphisms at higher frequency in their protease and RT coding region. In contrast, a significantly higher proportion of B viruses showed resistance to a range of antiretroviral drugs.

Remarks on the role of economic modeling

BACKGROUND

Despite the growing scholarly acceptance of quantitative evaluation methods, modelers still struggle to define an appropriate role for their work at the decision-making level.

GOAL

To make observations about the policy relevance of mathematical and economic policy modeling in HIV and sexually transmitted disease prevention and treatment.

RESULTS

The debate is framed within the context of the inevitability of decision making. Viewed in this light, models can inform choices between competing alternatives by leveraging existing information, integrating data from multiple sources, addressing "what if" questions, evaluating future scenarios, and providing a uniform metric for evaluation.

CONCLUSIONS

The goal of model-based evaluation should not be to supplant the decision maker, but rather to redefine the terms of the debate using quantitative methods that make the beliefs and values that lie at the heart of all difficult choices explicit.

HIV transmission and the cost-effectiveness of methadone maintenance

OBJECTIVES

This study determined the cost-effectiveness of expanding methadone maintenance treatment for heroin addiction, particularly its effect on the HIV epidemic.

METHODS

We developed a dynamic epidemic model to study the effects of increased methadone maintenance capacity on health care costs and survival, measured as quality-adjusted life-years (QALYs). We considered communities with HIV prevalence among injection drug users of 5% and 40%.

RESULTS

Additional methadone maintenance capacity costs $8200 per QALY gained in the high-prevalence community and $10,900 per QALY gained in the low-prevalence community. More than half of the benefits are gained by individuals who do not inject drugs. Even if the benefits realized by treated and untreated injection drug users are ignored, methadone maintenance expansion costs between $14,100 and $15,200 per QALY gained. Additional capacity remains cost-effective even if it is twice as expensive and half as effective as current methadone maintenance slots.

CONCLUSIONS

Expansion of methadone maintenance is cost-effective on the basis of commonly accepted criteria for medical interventions. Barriers to methadone maintenance deny injection drug users access to a cost-effective intervention that generates significant health benefits for the general population.

When is an HIV infection prevented and when is it merely delayed?

HIV prevention programs are typically evaluated using behavioral outcomes. Mathematical models of HIV transmission can be used to translate these behavioral outcomes into estimates of the number of HIV infections averted. Usually, intervention effectiveness is evaluated over a brief assessment period and an infection is considered to be prevented if it does not occur during this period. This approach may overestimate intervention effectiveness if participants continue to engage in risk behaviors. Conversely, this strategy underestimates the true impact of interventions by assuming that behavioral changes persist only until the end of the intervention assessment period. In this article, the authors (a) suggest a simple framework for distinguishing between HIV infections that are truly prevented and those that are merely delayed, (b) illustrate how these outcomes can be estimated, (c) discuss strategies for extrapolating intervention effects beyond the assessment period, and (d) highlight the implications of these findings for HIV prevention decision making.

HIV-1 diversity in France, 1996-1998. The AC 11 laboratory network

OBJECTIVE

To study the distribution of HIV-1 subtypes in France and to describe the characteristics of patients infected with non-B subtypes.

METHODS

All adults who tested HIV-1 positive on Western blot for the first time in one of the participating laboratories between September 1996 and March 1998 were eligible, whether or not they had been diagnosed previously elsewhere. Data on age, sex, country of birth, HIV-transmission group, dates of the last negative and first positive HIV test and clinical stage were collected. Serotyping was performed with a peptide subtype-specific enzyme immunoassay on each plasma sample and genotyping with heteroduplex mobility assay on each non-B serotype-infected patient. Patients characteristics were compared in B and non-B subtypes.

RESULTS

Of the 2168 HIV-positive patients included by 32 laboratories, subtype,results were available for 2042. Among those, 73.4% were men, 12.2% born in sub-Saharan Africa, 41.5% infected through heterosexual contact and 67.6% in CDC stage A. Among the 2042 patients, 1 725 (84.5%) were infected with B subtype. Among the 317 non-B subtypes, subtype A was predominant (66.9%); all other subtypes (C, D, E, F, G, H, O) were present. Factors independently associated with a non-B subtype were to be included in the Paris area [adjusted odds ratio (aOR), 1.6; 95% confidence interval (CI), 1.1-2.3], to be born in sub-Saharan Africa (aOR, 26.0; 95% CI, 17.5-37.8) and to be infected through heterosexual contact (aOR, 4.2; 95% CI, 2.8-6.4).

CONCLUSIONS

In France, although B subtype is still predominant, all non-B subtypes are now present. The diversity of HIV strains may affect diagnostic tests and clinical practice, especially viral load measurements. Moreover, the decreased susceptibility of non-B subtypes to antiretroviral drugs emphasizes the importance of surveillance of HIV diversity.

How HIV treatment advances affect the cost-effectiveness of prevention

OBJECTIVE

The cost-effectiveness of an HIV prevention program depends, in part, on its potential to avert HIV-related medical care costs. Recent advances in antiretroviral therapy have made HIV/AIDS treatment both more effective and more costly, which might make HIV prevention either more or less cost-effective. The objective of the present study was to explicate the relationship between the effectiveness and costs of HIV treatment and the cost-effectiveness of HIV prevention programs.

METHODS

A basic analytic framework was used to compare the cost-effectiveness of HIV prevention interventions with respect to different HIV/AIDS medical care scenarios. Algebra was used to calculate a cost-effectiveness threshold that distinguishes prevention programs that become more cost-effective when therapeutic advances simultaneously increase or decrease the cost and effectiveness of treatment from those that become less cost-effective. Recent estimates of the costs and consequences of combination antiretroviral therapy were used to illustrate the calculation method.

RESULTS

The advent of combination antiretroviral therapies for HIV has increased the cost-effectiveness of some, but not all, HIV prevention interventions.

CONCLUSIONS

Whether a particular prevention program becomes more or less cost-effective as a consequence of advancements in the medical treatment of HIV/AIDS depends upon the specific characteristics of both the program and the therapy.