Cost-effectiveness of improved treatment services for sexually transmitted diseases in preventing HIV-1 infection in Mwanza Region, Tanzania

Cost-effectiveness of HIV/AIDS interventions in Africa: a systematic review of the evidence

BACKGROUND

Evidence for cost-effectiveness of interventions for HIV/AIDS in Africa is fragmentary. Cost-effectiveness is, however, highly relevant. African governments face difficult choices in striking the right balance between prevention, treatment, and care, all of which are necessary to deal comprehensively with the epidemic. Reductions in drug prices have raised the priority of treatment, though treatment access is restricted. We assessed the existing cost-effectiveness data and its implications for value-for-money strategies to combat HIV/AIDS in Africa.

METHODS

We undertook a systematic review using databases and consultations with experts. We identified over 60 reports that measured both the cost and effectiveness of HIV/AIDS interventions in Africa. 24 studies met our inclusion criteria and were used to calculate standardised estimates of the cost (US$ for year 2000) per HIV infection prevented and per disability-adjusted life-year (DALY) gained for 31 interventions.

FINDINGS

Cost-effectiveness varied greatly between interventions. A case of HIV/AIDS can be prevented for $11, and a DALY gained for $1, by selective blood safety measures, and by targeted condom distribution with treatment of sexually transmitted diseases. Single-dose nevirapine and short-course zidovudine for prevention of mother-to-child transmission, voluntary counselling and testing, and tuberculosis treatment, cost under $75 per DALY gained. Other interventions, such as formula feeding for infants, home care programmes, and antiretroviral therapy for adults, cost several thousand dollars per infection prevented, or several hundreds of dollars per DALY gained.

INTERPRETATION

A strong economic case exists for prioritisation of preventive interventions and tuberculosis treatment. Where potentially exclusive alternatives exist, cost-effectiveness analysis points to an intervention that offers the best value for money. Cost-effectiveness analysis is an essential component of informed debate about priority setting for HIV/AIDS.

Human immunodeficiency virus and other sexually transmitted infections among female sex workers in two major cities in Papua New Guinea

BACKGROUND

Treatable sexually transmitted infections are very common in developing countries and quite often are inadequately treated or remain untreated despite the fact that they enhance the transmission of human immunodeficiency virus (HIV).

GOAL

To estimate the prevalence of HIV, syphilis, chlamydial infection, gonorrhea, and trichomoniasis among female sex workers in Port Moresby and Lae, Papua New Guinea, and to collect data on associated behaviors.

STUDY DESIGN

Self-identified female sex workers recruited through our peer-mediated sexually transmitted disease (STD)/HIV risk-reduction community outreach program were invited to participate in the study. Participants underwent pretest counseling, were interviewed, and were asked to self-collect vaginal swab specimens for the detection of STDs and to provide 10 mL of blood for HIV and syphilis testing.

RESULTS

A total of 407 female sex workers, 207 in Port Moresby and 200 in Lae, were enrolled in the study. The overall prevalence rates of HIV, syphilis, genital chlamydial infection, gonorrhea, and trichomoniasis among these women were estimated to be 10%, 32%, 31%, 36%, and 33%, respectively. The sex workers in Port Moresby had a significantly higher HIV infection rate (17%) than those in Lae (3%) and a significantly lower trichomoniasis rate (21%) than those in Lae (44%). Mixed infections were common, occurring in 45% of the cases. Despite a high rate of symptoms, the rate of treatment-seeking was low. Condom use among the sex workers was very inconsistent; 85% reported that they did not use condoms at all times when having sex with their clients. Common reasons cited were dislike by clients, unavailability, alcohol use, and familiarity with a client.

CONCLUSIONS

STDs are very common among female sex workers in Port Moresby and Lae and very often present as multiple infections. Despite STD/HIV awareness campaigns, unsafe sex-particularly irregular use of condoms-continues among sex workers and their clients. Barriers to safer sexual behavior need to be addressed, as do improvements in provision of STD services.

Multiplexed immunoassays by flow cytometry for diagnosis and surveillance of infectious diseases in resource-poor settings

An accurate, rapid and cost-effective diagnosis is the cornerstone of efficient clinical and epidemiological management of infections. Here we discuss the relevance of an emerging technology, multiplexed immunoassays read by flow cytometry, for the diagnosis of infectious diseases. In these assays, multiple fluorescent microspheres, conjugated to different antigens or antibodies, constitute the solid phase for detecting antibodies or antigens in biological samples. These assays seem to be more sensitive than traditional immunoassays, have a high throughput capacity, and provide a wide analytical dynamic range. Additionally, they have multiplexing ability-ie, they are capable of measuring multiple antibodies or antigens simultaneously. We discuss four different areas where this technology could make an impact in resource-poor settings: (i) infections causing rash and fever in children; (ii) sero-epidemiological studies on vaccine-preventable diseases; (iii) management of genital ulcers and vaginal discharge; and (iv) screening of infections in blood banking. We predict a widespread use for a new breed of small, affordable, practical flow cytometers as field instruments for replacing ELISA and RIA tests, which will also be capable of doing cellular immunological tests such as CD4+ T-cell enumeration and Plasmodium falciparum detection in whole blood.

A systematic review of the epidemiologic interactions between classic sexually transmitted diseases and HIV: how much really is known?

BACKGROUND

Many studies have explored the role of "classic" sexually transmitted diseases (STDs) in determining the pattern of HIV epidemics. However, the many different STDs may contribute in different ways, at different magnitudes.

GOAL

To review available studies on the bidirectional interactions of HIV and STDs to explore the extent of current knowledge on the different influences of the varied STDs in heterosexual HIV epidemics.

METHODS

Longitudinal studies on susceptibility and controlled studies on infectiousness and duration of disease identified on electronic databases through reference lists and citation indices up to the end of 1999 were systematically reviewed, including meta-analyses assessing the influence of STDs on susceptibility to HIV.

RESULTS

Studies have a clear publication bias with a significant result that hinders robust interpretation. However, genital ulcerative disease appears to have a greater impact than nonulcerative disease, and men are more affected than women by the effects of STDs on susceptibility to HIV. There is evidence that STDs increase the infectiousness of HIV from men to women, whereas the evidence is more equivocal for the infectiousness of women. Few studies identify the impact of different STDs, and there is a marked lack of studies investigating the impact of HIV infection on the transmission of other STDs.

CONCLUSIONS

A large body of work has measured the association between STDs and HIV. However, publication bias and gaps in the focus of studies mean that a detailed, quantitative understanding of the interaction requires much more attention.

Critical issues in the economic evaluation of interventions against communicable diseases

Economic appraisal seeks to provide policy-makers with guidance about how scarce resources can be used to derive the greatest possible social benefit. Its use in the health sector has increased dramatically over the last decade although much of it has been focused on the problems of the more developed countries. The relatively sparse literature on communicable diseases has been dominated by interventions related to HIV/AIDS, hepatitis, malaria and tropical diseases. Reviews of this literature from the perspective of specific conditions such as Hepatitis B are already available, and recently the entire literature has been evaluated against the technical criteria for economic evaluations published in standard textbooks. Accordingly, this paper focuses on issues which would make economic appraisal more useful to policy-makers than it currently is. Given that few countries have the resources to undertake all the necessary analysis in their own settings, it is important that studies in one setting are undertaken in a way that allow generalisability to similar settings. Some of the most important challenges this poses for cost-effectiveness analysis (CEA) are identified. Firstly, incremental analysis is appropriate to local decision making when policy-makers are constrained to keep the current interventions and can consider only marginal improvements. However, it does not allow re-evaluation of existing interventions and is not transferable across settings. A version of Generalised CEA is proposed as an alternative. Secondly, data on costs and effectiveness are often not presented appropriately. The challenge for effectiveness is to adjust the evidence from efficacy studies to allow for different patient or population groups, and local variations in adherence, coverage, and infrastructure. For costs, it is important for studies to report the physical resources used in an intervention as well as unit prices. Thirdly, some long-term effects are still not well incorporated into CEA, especially those affecting child development and drug resistance. These questions are technically challenging and require more concerted efforts over the next few years. Finally, it is important for analysts to provide decision-makers with estimates of the resources that would be required to implement interventions claimed to be cost-effective. These improvements would better enable the evidence from economic analyses to enter the policy debate and be weighed against the other goals and objectives of the health system when allocating scarce resources.

Operational performance of an STD control programme in Mwanza Region, Tanzania

OBJECTIVES

To describe important details of the design and operational features of the Mwanza sexually transmitted diseases (STD) control programme. To assess the feasibility of the intervention, the distribution of STD syndromes observed, the clinical effectiveness of syndromic STD case management, the utilisation of STD services by the population, and the quality of syndromic STD services delivered at rural health units.

METHODS

The intervention was integrated into rural primary healthcare (PHC) units. It comprised improved STD case management using the syndromic approach, facilitated by a regional programme office which ensured the training of health workers, a reliable supply of effective drugs, and regular support supervision. Five studies were performed to evaluate operational performance: (i) a survey of register books to collect data on patients presenting with STDs and reproductive tract infections (RTIs) to rural health units with improved STD services, (ii) a survey of register books from health units in communities without improved services, (iii) a survey of register books from referral clinics, (iv) a home based cross sectional study of STD patients who did not return to the intervention health units for follow up, (v) a cross sectional survey of reported STD treatment seeking behaviour in a random cohort of 8845 adults served by rural health units.

RESULTS

During the 2 years of the Mwanza trial, 12,895 STD syndromes were treated at the 25 intervention health units. The most common syndromes were urethral discharge (67%) and genital ulcers (26%) in men and vaginal discharge (50%), lower abdominal tenderness (33%), and genital ulcers (13%) in women. Clinical treatment effectiveness was high in patients from whom complete follow up data were available, reaching between 81% and 98% after first line treatment and 97%-99% after first, second, and third line treatment. Only 26% of patients referred to higher levels of health care had presented to their referral institutions. During the trial period, data from the cohort showed that 12.8% of men and 8.6% of women in the intervention communities experienced at least one STD syndrome. Based on various approaches, utilisation of the improved health units by symptomatic STD patients in these communities was estimated at between 50% and 75%. During the first 6 months of intervention attendance at intervention units increased by 53%. Thereafter, the average attendance rate was about 25% higher than in comparison communities. Home visits to 367 non-returners revealed that 89% had been free of symptoms after treatment, but 28% became symptomatic again within 3 months of treatment. 100% of these patients reported that they had received treatment, but only 74% had been examined, only 57% had been given health education, and only 30% were offered condoms. Patients did not fully recall which treatment they had been given, but possibly only 63% had been treated exactly according to guidelines.

CONCLUSIONS

This study demonstrated that it is feasible to integrate effective STD services into the existing PHC structure of a developing country. Improved services attract more patients, but additional educational efforts are needed to further improve treatment seeking behaviour. Furthermore, clear treatment guidelines, a reliable drug supply system, and regular supervision are critical. All efforts should be made to treat patients on the spot, without delay, as referral to higher levels of care led to a high number of dropouts. The syndromic approach to STD control should be supported by at least one reference clinic and laboratory per country to ensure monitoring of prevalent aetiologies, of the development of bacterial resistance, and of the effectiveness of the syndromic algorithms in use.

STD management by private pharmacies in Hanoi: practice and knowledge of drug sellers

BACKGROUND

Prompt treatment of sexually transmitted infections may reduce the incidence of HIV/AIDS infections. With health sector reforms private pharmacies are increasingly the first and only contact with health delivery services.

OBJECTIVES

To find out how patients with STDs are treated at private pharmacies in Hanoi, and what drug sellers know about STD management.

METHODS

Five simulated clients were taught to adopt a scenario stating that their friend had a urethral discharge. They visited 60 randomly selected private pharmacies in urban Hanoi and noted all questions asked, advice offered, and treatment given. Afterwards interviewers administered a semistructured questionnaire to all people working in the 60 pharmacies.

RESULTS

Drug treatment was given in 84% of the 297 encounters averaging 1.5 drugs and 1.2 antibiotics per encounter. Quinolones were given 188 times. No dispensing was adequate for chlamydia or was in accordance with the national guidelines. No questions were asked in 55% of encounters and no advice was given in 61%. Questions on sexual activity were asked in 23% (69) of cases and about the health of the partner twice (1%). Advice to practise safe sex was given in 1% of encounters and for the partner to seek treatment only once. Of 69 questionnaires administered 51% said they would refer to a doctor, 16% said they would ask about the sexual activity 1% said they would ask about the health of the partner, 7% said they would advise using a condom, and 1% advised telling the partner to seek treatment. Even after prompting, 61% would ask no questions and 80% would give no advice.

CONCLUSIONS

Even though 74% of pharmacists and drug sellers know that they should not treat STD patients, 84% actually did. None gave syndromically correct treatment. In both the questionnaire and during the simulated client methods, numbers advising on partner notification and condom use were very poor. Educational or peer awareness interventions are urgently needed among private pharmacists in Vietnam.

Cost-effectiveness of voluntary HIV-1 counselling and testing in reducing sexual transmission of HIV-1 in Kenya and Tanzania

BACKGROUND

Access to HIV-1 voluntary counselling and testing (VCT) is severely limited in less-developed countries. We undertook a multisite trial of HIV-1 VCT to assess its impact, cost, and cost-effectiveness in less-developed country settings.

METHODS

The cost-effectiveness of HIV-1 VCT was estimated for a hypothetical cohort of 10000 people seeking VCT in urban east Africa. Outcomes were modelled based on results from a randomised controlled trial of HIV-1 VCT in Tanzania and Kenya. Our main outcome measures included programme cost, number of HIV-1 infections averted, cost per HIV-1 infection averted, and cost per disability-adjusted life-year (DALY) saved. We also modelled the impact of targeting VCT by HIV-1 prevalence of the client population, and the proportion of clients who receive VCT as a couple compared with as individuals. Sensitivity analysis was done on all model parameters.

FINDINGS

HIV-1 VCT was estimated to avert 1104 HIV-1 infections in Kenya and 895 in Tanzania during the subsequent year. The cost per HIV-1 infection averted was US$249 and $346, respectively, and the cost per DALY saved was $12.77 and $17.78. The intervention was most cost-effective for HIV-1-infected people and those who received VCT as a couple. The cost-effectiveness of VCT was robust, with a range for the average cost per DALY saved of $5.16-27.36 in Kenya, and $6.58-45.03 in Tanzania. Analysis of targeting showed that increasing the proportion of couples to 70% reduces the cost per DALY saved to $10.71 in Kenya and $13.39 in Tanzania, and that targeting a population with HIV-1 prevalence of 45% decreased the cost per DALY saved to $8.36 in Kenya and $11.74 in Tanzania.

INTERPRETATION

HIV-1 VCT is highly cost-effective in urban east African settings, but slightly less so than interventions such as improvement of sexually transmitted disease services and universal provision of nevirapine to pregnant women in high-prevalence settings. With the targeting of VCT to populations with high HIV-1 prevalence and couples the cost-effectiveness of VCT is improved significantly.

Economic issues in the prevention of vertical transmission of HIV

In the absence of interventions, 20% of infants born to women infected with HIV acquire infection from their mother at or before delivery. A further 15% are infected through breast feeding. Prenatal testing for HIV allows infected women to be reliably identified so that they can receive antiretroviral therapy and, in countries with safe water supplies, be advised not to breast feed. These and other interventions can reduce the risk of transmission to 5% or less. Economic evaluations of prenatal testing for HIV are reviewed and compared in this article, and future research priorities outlined. These studies set the costs of testing and intervention against the averted lifetime costs of paediatric infection, and generate estimates of the HIV prevalence threshold above which there would be a net cost saving, or calculate the cost per life-year saved given a particular prevalence. In the developed world, prenatal testing has been adopted in many countries, and recent economic analyses broadly support this. Future research is likely to focus on the incremental benefits of different antiretroviral regimens in lowering transmission rates still further, with or without elective caesarean section, and the possibility that some may lead to adverse effects in uninfected infants exposed to them in utero. Some earlier assessments in resource-poor settings concluded that prenatal testing was unaffordable or of doubtful cost effectiveness. This negative conclusion appears to be the result of very low estimates of the lifetime costs of paediatric HIV infection, together with developed world conceptions of pre-test counselling. The demonstration that nevirapine reduces transmission risk at a low cost has transformed the outlook, and there is hope that antiretrovirals can act prophylactically to prevent infection of the breast-fed child. However, to achieve a sustained reduction in vertical transmission there may be a need to evaluate the need for a strengthened infrastructure to deliver prenatal HIV testing and treatment, as well as programmes to reduce HIV incidence in adults.

Extent to which low-level use of antiretroviral treatment could curb the AIDS epidemic in sub-Saharan Africa

BACKGROUND

Despite growing international pressure to provide HIV-1 treatment to less-developed countries, potential demographic and epidemiological impacts have yet to be characterised. We modelled the future impact of antiretroviral use in South Africa from 2000 to 2005.

METHODS

We produced a population projection model that assumed zero antiretroviral use to estimate the future demographic impacts of the HIV-1 epidemic. We also constructed four antiretroviral-adjusted scenarios to estimate the potential effect of antiretroviral use. We modelled total drug cost, cost per life-year gained, and the proportion of per-person health-care expenditure required to finance antiretroviral treatment in each scenario.

FINDINGS

With no antiretroviral use between 2000 and 2005, there will be about 276,000 cumulative HIV-1-positive births, 2,302,000 cumulative new AIDS cases, and the life expectancy at birth will be 46.6 years by 2005. By contrast, 110,000 HIV-1-positive births could be prevented by short-course antiretroviral prophylaxis, as well as a decline of up to 1 year of life expectancy. The direct drug costs of universal coverage for this intervention would be US$54 million--less than 0.001% of the per-person health-care expenditure. In comparison, triple-combination treatment for 25% of the HIV-1-positive population could prevent a 3.1-year decline in life expectancy and more than 430,000 incident AIDS cases. The drug costs of this intervention would, however, be more than $19 billion at present prices, and would require 12.5% of the country's per-person health-care expenditure.

INTERPRETATION

Although there are barriers to widespread HIV-1 treatment, limited use of antiretrovirals could have an immediate and substantial impact on South Africa's AIDS epidemic.

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.

Model-based evaluation of single-round mass treatment of sexually transmitted diseases for HIV control in a rural African population

OBJECTIVES

To compare the impact of single-round mass treatment of sexually transmitted diseases (STD), sustained syndromic treatment and their combination on the incidence of HIV in rural Africa.

METHODS

We studied the effects of STD interventions by stochastic simulation using the model STDSIM. Parameters were fitted using data from a trial of improved STD treatment services in Mwanza, Tanzania. Effectiveness was assessed by comparing the prevalences of gonorrhoea, chlamydia, syphilis and chancroid, and the incidence of HIV, in the general adult population in simulations with and without intervention.

RESULTS

Single-round mass treatment was projected to achieve an immediate, substantial reduction in STD prevalences, which would return to baseline levels over 5-10 years. The effect on syphilis was somewhat larger if participants cured of latent syphilis were not immediately susceptible to re-infection. At 80% coverage, the model projected a reduction in cumulative HIV incidence over 2 years of 36%. A similar impact was achieved if treatment of syphilis was excluded from the intervention or confined to those in the infectious stages. In comparison with sustained syndromic treatment, single-round mass treatment had a greater short-term impact on HIV (36 versus 30% over 2 years), but a smaller long-term impact (24 versus 62% over 10 years). Mass treatment combined with improved treatment services led to a rapid and sustained fall in HIV incidence (57% over 2 years; 70% over 10 years).

CONCLUSIONS

In populations in which STD control can reduce HIV incidence, mass treatment may, in the short run, have an impact comparable to sustained syndromic treatment. Mass treatment combined with sustained syndromic treatment may be particularly effective.

Reproductive-tract infections in women in low-income, low-prevalence situations: assessment of syndromic management in Matlab, Bangladesh

BACKGROUND

In the control of reproductive-tract infections, including sexually transmitted infections (STIs), in low-income and middle-income countries, WHO recommends syndromic management for individuals with symptoms. This intervention was initially developed in areas where prevalence of such infections is high. We investigated the clinical effectiveness and cost of this approach among a group of women with a low prevalence of infection.

METHODS

During a 5-month period, we investigated all women complaining of abnormal vaginal discharge and seeking care at maternal and child health/family-planning centres in Matlab, Bangladesh, for the presence of laboratory-diagnosed reproductive-tract infections and STIs. Syndromic diagnoses made by trained health-care workers were compared with laboratory diagnosis of infection. We then calculated the costs of treating women by means of the recommended WHO algorithm and an adapted algorithm incorporating use of a speculum and simple diagnostic tests.

FINDINGS

The prevalence of endogenous infections among 320 women seen was 30%. Cervical infections (Neisseria gonorrhoeae and Chlamydia trachomatis) were found in only three women. The WHO algorithm had a high sensitivity (100%) but a low specificity (zero for bacterial vaginosis, candida, and Trichomonas vaginalis). The speculum-based algorithm had a low sensitivity (between zero and 59%) but a higher specificity (79-97%). Between 36% and 87% of costs would have been spent on uninfected women.

INTERPRETATION

The high rate of overtreatment in the population studied carries both financial and social costs--the latter in potentially exposing women misdiagnosed as having an STI to threats of domestic disruption or even violence. We make recommendations for management programmes in areas of low STI prevalence and low income.

Providing low-cost sexually transmitted diseases services in two semi-urban health centers in Central African Republic (CAR): characteristics of patients and patterns of health care-seeking behavior

BACKGROUND

While treatment of symptomatic sexually transmitted diseases (STDs) has been shown to reduce the incidence of HIV infection, there are few published reports describing the delivery of high quality STD care in Africa.

GOAL

To test the feasibility of providing comprehensive, affordable STD services through the existing primary care infrastructure.

DESIGN

STD treatment services using a syndromic' approach were established in two semi-urban hospital outpatient departments (OPD) in Central African Republic (CAR). A dedicated paramedical provider took a clinical history, performed an examination, explained the diagnosis and the importance of referring partners, dispensed drugs, and offered partner referral vouchers. A fee-for-service system was used to resupply drugs initially purchased with project funds.

RESULTS

Of 9,552 visits by index patients and partners over a 28-month period starting in October 1993, 60% were made by women; of these women, 90% were symptomatic, 77% had "vaginal discharge," 70% "lower abdominal pain," and 7% "genital ulcer." Among men, 64 % were symptomatic, 38 % had "urethral discharge," and 14% "genital ulcer." Half of all symptomatic patients presented within 1 week of the onset of symptoms; 44% of men compared to 18% of women had sought care elsewhere before the clinic visit. The average cost per STD treated with recommended drugs was $3.90. Etiologic data from subpopulations in both sites suggest that a high proportion of patients was infected with an STD.

CONCLUSIONS

Comprehensive yet affordable care for STDs in persons (and their partners) who recognize symptoms is feasible and should be widely implemented in primary care systems to prevent the spread and complications of STDs and HIV in Africa.

Cost effectiveness of single-dose nevirapine regimen for mothers and babies to decrease vertical HIV-1 transmission in sub-Saharan Africa

BACKGROUND

Identification of economical interventions to decrease HIV-1 transmission to children is an urgent public-health priority in sub-Saharan Africa. We assessed the cost effectiveness of the HIVNET 012 nevirapine regimen.

METHODS

We assessed cost effectiveness in a hypothetical cohort of 20,000 pregnant women in sub-Saharan Africa. Our main outcome measures were programme cost, paediatric HIV-1 cases averted, cost per case averted, and cost per disability-adjusted life-year (DALY). We compared HIVNET 012 with other short-course antiretroviral regimens. We also compared two implementation strategies: counselling and HIV-1 testing before treatment (targeted treatment), or nevirapine for all pregnant women (universal treatment, no counselling and testing). We did univariate and multivariate sensitivity analyses.

FINDINGS

For universal treatment with 30% HIV-1 seroprevalence, the HIVNET 012 regimen would avert 603 cases of HIV-1 in babies, cost US$83,333, and generate 15,862 DALYs. The associated cost-effectiveness ratios were $138 per case averted or $5.25 per DALY. At 15% seroprevalence, the universal treatment option would cost $83,333 and avert 302 cases at $276 per case averted or $10.51 per DALY. For targeted treatment at 30% seroprevalence, HIVNET 012 would cost $141,922 and avert 476 cases at $298 per case averted or $11.29 per DALY. With seroprevalence higher than 3.0% for universal and 4.5% for targeted treatment, the HIVNET 012 regimen was likely to be as cost effective as other public-health interventions. The cost effectiveness of HIVNET 012 was robust under a wide range of parameters in the sensitivity analysis.

INTERPRETATION

The HIVNET 012 regimen can be highly cost-effective in high seroprevalence settings. In lower seroprevalence areas, when multidose regimens are not cost effective, nevirapine therapy could have a major public-health impact at a reasonable cost.

Prevention and intervention of sexually transmitted diseases in adolescents

Adolescents are the age group at greatest risk for acquiring sexually transmitted diseases. Sexually transmitted disease intervention programs based on behavioral change theories that emphasize self-efficacy and motivational enhancement may provide adolescents with skills to change risk behavior patterns. School-based sexually transmitted disease programs can reach the majority of the at-risk adolescent population. Community-based programs attempt to change community norms for a targeted high-risk population and are particularly helpful in reaching adolescents who are not in school. Finally, clinic-based interventions serve adolescents seeking health care, not only encouraging abstinence and safer sex practices for prevention of sexually transmitted disease but also providing opportunities for early detection and treatment. All three have their advantages, but each may neglect a significant portion of the population at risk. Development of structured sexually transmitted disease intervention programs utilizing school, community, and clinic settings merits further study.

The use of epidemiologic mass treatment and syndrome management for sexually transmitted disease control

BACKGROUND

Epidemiologic mass treatment and syndrome management are two sexually transmitted disease (STD) control strategies that are receiving increased attention internationally. The former is a population-based intervention, whereas the latter attempts to improve the quality and efficiency of clinic-based STD case management.

METHODS

The published literature on these subjects was reviewed.

RESULTS

Epidemiologic mass treatment refers to treatment of whole communities (mass treatment) or high-risk subgroups within communities (targeted presumptive treatment) based on high STD prevalence rates. Syndrome management overcomes many obstacles to provision of quality STD case management by basing treatment decisions on recognition of easily identifiable syndromes. Experience with application of these strategies is summarized, and their possible use as STD control measures in communities with similar conditions is discussed.

CONCLUSIONS

Epidemiologic mass treatment may be an effective approach to rapidly reduce STD transmission in high prevalence communities, especially when high-risk core groups are effectively reached. Once high prevalence rates are brought down, however, longer term strategies, including improved STD case management, are essential to maintain reduced rates.

Foundations for effective strategies to control sexually transmitted infections: voices from rural Kenya

Achieving maximal benefit from clinic-based, sexually transmitted infection (STI) control strategies requires that persons seek treatment at public clinics. Community-based, ethnographic research methods were used to examine patterns of health-seeking behavior for sexually transmitted infections in western Kenya. Illness narratives of sexually transmitted infections provided the basis for an analysis of sequential steps in health-seeking behavior, namely recognition, classification, overcoming stigma, identification of treatment options and selection of a course of therapy. A variety of terms were used to identify STI, including multiple terms referring to "women's disease". The stigma associated with STI, reflected in the terminology, was based on a set of beliefs on the causes, contagiousness and sequelae of STI, and resulted in delays in seeking treatment. Five commonly used treatment options were identified, with multiple sources of care often used concurrently. The desire for privacy, cost and belief in the efficacy of traditional medicines strongly influenced health-seeking behaviour. A belief that sexually transmitted infections must be transmitted in order to achieve cure was professed by several respondents and promoted by a traditional healer. Implications for STI control strategies are derived, including the development of educational messages and the design of clinics.

From epidemiological synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection

OBJECTIVES

To review the scientific data on the role of sexually transmitted diseases (STDs) in sexual transmission of HIV infection and discuss the implications of these findings for HIV and STD prevention policy and practice.

METHODS

Articles were selected from a review of Medline, accessed with the OVID search engine. The search covered articles from January 1987 to September 1998 and yielded 2101 articles. Methods used to uncover articles which might have been missed included searching for related articles by author, and combing literature reviews. In addition, all abstracts under the category "sexually transmitted diseases" from the XI and XII International Conferences on AIDS (Vancouver 1996 and Geneva 1998) and other relevant scientific meetings were reviewed. Efforts were made to locate journal articles which resulted from the research reported in the identified abstracts. All original journal articles and abstracts which met one of the following criteria were included: (1) studies of the biological plausibility or mechanism of facilitation of HIV infectiousness or susceptibility by STDs, (2) prospective cohort studies (longitudinal or nested case-control) which estimate the risk of HIV infection associated with specific STDs or STD syndromes, or (3) intervention studies which quantitate the effect which STD treatment can have on HIV incidence.

RESULTS

Strong evidence indicates that both ulcerative and non-ulcerative STDs promote HIV transmission by augmenting HIV infectiousness and HIV susceptibility via a variety of biological mechanisms. These effects are reflected in the risk estimates found in numerous prospective studies from four continents which range from 2.0 to 23.5, with most clustering between 2 and 5. The relative importance of ulcerative and non-ulcerative STDs appears to be complex. Owing to the greater frequency of non-ulcerative STDs in many populations, these infections may be responsible for more HIV transmission than genital ulcers. However, the limited reciprocal impact of HIV infection on non-ulcerative STDs and the evidence that non-ulcerative STDs may increase risk primarily for the receptive partner (rather than bidirectionally) may modulate the impact of these diseases. The results of two community level randomised, controlled intervention trials conducted in Africa suggest that timely provision of STD services can substantially reduce HIV incidence, but raise additional questions about the optimal way to target and implement these services to achieve the greatest effect on HIV transmission.

CONCLUSIONS

Available data leave little doubt that other STDs facilitate HIV transmission through direct, biological mechanisms and that early STD treatment should be part of a high quality, comprehensive HIV prevention strategy. Policy makers, HIV prevention programme managers, and providers should focus initial implementation efforts on three key areas: (i) improving access to and quality of STD clinical services; (ii) promoting early and effective STD related healthcare behaviours; and (iii) establishing surveillance systems to monitor STD and HIV trends and their interrelations.

Antiretroviral drugs as a public health intervention for pregnant HIV-infected women in rural South Africa: an issue of cost-effectiveness and capacity

OBJECTIVE

To estimate cost-effectiveness and capacity requirements for providing antiretroviral drugs to pregnant HIV-infected women in rural South Africa.

SETTING

Hlabisa health district, where HIV prevalence among pregnant women was 26.0% in 1997.

METHODS

Calculation of the number of paediatric HIV infections averted under three scenarios, and their cost. No intervention was compared with scenario A (zidovudine delivered within current infrastructure), scenario B (zidovudine delivered through enhanced infrastructure), and scenario C (short-course zidovudine plus lamivudine delivered through enhanced infrastructure). Cost-effectiveness was defined as cost per infection averted and cost per potential life-year gained. Capacity was determined in terms of staff and infrastructure required to effectively implement the scenarios.

RESULTS

With no intervention, 657 paediatric HIV infections were projected for 1997. In scenario A this could be reduced by 15% at a cost of US$ 574 825, in scenario B by 42% at US$ 1520770, and in scenario C by 47% at US$ 764901. In scenario C, drugs accounted for 76% of costs, whereas additional staff accounted for 18%. Cost per infection averted was US$ 2492 and cost per potential life-year gained (discounted at 3%) was US$ 88. Cost of scenario C was equivalent to 14% of the 1997 district health budget. At least 12 extra counsellors and nurses and one laboratory technician, together with substantial logistical and managerial support, would be needed to deliver an effective intervention.

CONCLUSION

Although antiretrovirals may be relatively cost-effective in this setting, the budget required is currently unaffordable. Developing the capacity required to deliver the intervention would pose both a major challenge, and an opportunity, to improve health services.