Decrease In HIV Prevalence Research Articles

SP3-67 Kaposi sarcoma incidence in Uganda and Zimbabwe, before and during HIV/AIDS epidemic

IntroductionWe described Kaposi sarcoma (KS) incidence changes during the AIDS emergence and subsequently in Zimbabwe with a high prevalence of HIV infection and Uganda with an intermediate HIV/AIDS prevalence and...

S7.3 Impact of the Avahan intervention on HIV/STI transmission amongst high and low-risk groups: an interim modelling assessment

ObjectiveTo estimate the potential HIV-impact of Avahan, the India AIDS Initiative, among targeted high-risk groups (including female sex workers (FSWs), their clients and men who have sex with men (MSM))...

Applications of geospatial analysis to surveillance data: a spatial examination of HIV/AIDS prevalence in Zambia

Techniques of spatial statistics and GIS are applied to socio-economic, demographic and HIV sentinel data to characterize the geographical distribution of HIV prevalence in Zambia and to estimate current prevalence rates. Maps of the 4 years under study (i.e. 1994, 1998, 2002 and 2004) reveal a spatial variation in HIV prevalence with urban and provincial districts having higher prevalence than rural areas. However, there was an overall trend of decrease in HIV prevalence across the country. The year 2004 exhibited the most reduction, coinciding with protective sexual behavior campaigns operating in the country. Risk factors for HIV prevalence included literacy rates, unemployment, poverty and urban residency. Analysis of regression residual maps indicated high spatial autocorrelation: Moran’s I value was 0.28 (z = 4.12 and p < 0.000) and a highly significant Robust LM (lag; p < 0.00000) suggestive of contagious and hierarchic spatial diffusion processes. High HIV prevalence rates among interdependent districts and locational similarity patterns suggest that HIV control programs in the country would require an integrated approach combining HIV prevention messages as well as an understanding of social and cultural interactions between interdependent districts that produce behavioral diffusion of HIV prevalence rates.

Minimal impact of circumcision on HIV acquisition in men who have sex with men

Men who have sex with men (MSM) are disproportionately affected by HIV. The proven efficacy of circumcision in reducing the risk of HIV acquisition among African heterosexual males has raised the question of whether this protective effect may extend to MSM populations. We examined the potential impact of circumcision on an HIV epidemic within a population of MSM. A mathematical model was developed to simulate HIV transmission in an MSM population. The model incorporated both circumcision and seropositioning, and was used to predict the reduction in HIV prevalence and incidence as a result of the two interventions. Estimates for the time required to achieve these gains were also calculated. We derive simple formulae for the decrease in HIV prevalence with increased circumcision. Our model predicts that if an initially uncircumcised MSM population in a developed country with a baseline HIV prevalence of 10% underwent universal circumcision, HIV incidence would only be reduced to 95% of pre-intervention levels and HIV prevalence to 9.6% after 20 years. In the longer term, our model predicts that prevalence would only decrease from 10% to 6%, but this would take several generations to achieve. The effectiveness of circumcision increases marginally with higher degrees of seropositioning. The results of these calculations suggest that circumcision as a public health intervention will not produce a substantial decrease in HIV prevalence or incidence among MSM in the near future, and only modest reductions are achievable in the long-term.

Estimating Vertically Acquired HIV Infections and the Impact of the Prevention of Mother-to-Child Transmission Program in Zimbabwe

The World Health Organization recommends a single-dose nevirapine (NVP) regimen for prevention of mother-to-child transmission (PMTCT) of HIV in settings without the capacity to deliver more complex regimens, but the population-level impact of this intervention has rarely been assessed. A decision analysis model was developed, parameterized, and applied using local epidemiologic and demographic data to estimate vertical transmission of HIV and the impact of the PMTCT program in Zimbabwe up to 2005. Between 1980 and 2005, of approximately 10 million children born in Zimbabwe, a cumulative 504,000 (range: 362,000 to 665,000) were vertically infected with HIV; 59% of these infections occurred in nonurban areas. Mother-to-child transmission (MTCT) of HIV decreased from 8.2% (range: 6.0% to 10.7%) in 2000 to 6.2% (range: 4.9% to 8.9%) in 2005, predominantly attributable to declining maternal HIV prevalence rather than to the PMTCT program. Between 2002 and 2005, the single-dose NVP PMTCT program may have averted 4600 (range: 3900 to 7800) infections. In 2005, 32% (range: 26% to 44%) and 4.0% (range: 2.7% to 6.2%) of infections were attributable to breast-feeding and maternal seroconversion, respectively, and the PMTCT program reduced infant infections by 8.8% (range: 5.5% to 12.1%). Twice as many infections could have been averted had a more efficacious but logistically more complex NVP + zidovudine regimen been implemented with similar coverage (50%) and acceptance (42%). The decline in MTCT from 2000 to 2005 is attributable more to the concurrent decrease in HIV prevalence in pregnant women than to PMTCT at the current level of rollout. To improve the impact of PMTCT, program coverage and acceptance must be increased, especially in rural areas, and local infrastructure must then be strengthened so that single-dose NVP can be replaced with a more efficacious regimen.

Changes in HIV Prevalence and Risk Among New Injecting Drug Users in a Russian City of High HIV Prevalence

To measure HIV prevalence and associated risk factors among recent initiates into drug injecting in 2001 and 2004 in Togliatti City, Russian Federation. Two unlinked, anonymous, cross-sectional, community-recruited surveys of injecting drug users (IDUs) with oral fluid samples for anti-HIV testing. IDUs completed an interviewer-administered questionnaire, and oral fluid samples were tested for antibodies to HIV. Demographic characteristics and injecting risk behaviors were compared between subsamples of IDUs who reported injecting for 3 years or less in each of the survey years, 2001 (n = 138) and 2004 (n = 96). Univariable and multivariable analyses explored risk factors with anti-HIV among these new injectors. Among IDUs overall, although HIV prevalence was high, a lower prevalence was found in 2004 (38.5%, 95% confidence interval [CI]: 34.1 to 42.9) than in 2001 (56%, 95% CI: 51.2 to 60.8). A significantly lower prevalence of HIV was found among new injectors in 2004 (11.5%, 95% CI: 5.0 to 17.9) than in 2001 (55.2%, 95% CI: 46.7 to 63.8). Proportionally, fewer new injectors reported injecting daily, injecting with used needles/syringes, and frontloading in 2004 compared with 2001. Decreased odds of anti-HIV were associated with being recruited in 2004 and with a history of drug treatment. Increased odds of HIV were associated with exchanging sex, duration of injection, and frontloading. Findings indicate a decrease in HIV prevalence among new injectors between 2001 and 2004 and emphasize the role of provision of needle/syringes through pharmacies and providing access to voluntary HIV testing. These findings have implications for other cities in which explosive HIV outbreaks have occurred.

HIV incidence and poverty in Manicaland, Zimbabwe: is HIV becoming a disease of the poor?

In Zimbabwe, socioeconomic development has a complicated and changeable relationship with HIV infection. Longitudinal data are needed to disentangle the cyclical effects of poverty and HIV as well as to separate historical patterns from contemporary trends of infection. We analysed a large population-based cohort in eastern Zimbabwe. The wealth index was measured at baseline on the basis of household asset ownership. The associations of the wealth index with HIV incidence and mortality, sexual risk behaviour, and sexual mixing patterns were analysed. The largest decreases in HIV prevalence were in the top third of the wealth index distribution (tercile) in both men at 25% and women at 21%. In men, HIV incidence was significantly lower in the top wealth index tercile (15.4 per 1000 person-years) compared with the lowest tercile (27.4 per 1000 person-years), especially among young men. Mortality rates were significantly lower in both men and women of higher wealth index. Men of higher wealth index reported more sexual partners, but were also more likely to use condoms. Better-off women reported fewer partners and were less likely to engage in transactional sex. Partnership data suggests increasing like-with-like mixing in higher wealth groups resulting in the reduced probability of serodiscordant couples. HIV incidence and mortality, and perhaps sexual risk, are lower in higher socioeconomic groups. Reduced vulnerability to infection, led by the relatively well off, is a positive trend, but in the absence of analogous developments in vulnerable groups, HIV threatens to become a disease of the poor.

Decline in HIV prevalence among women of childbearing age in Moshi urban, Tanzania

The objective of this study was to describe trends over time in HIV prevalence, sexually transmitted infections (STIs) and sexual behaviour among women in Moshi urban, Tanzania. Two cross-sectional studies were conducted in 1999 and in 2002-04 among women attending three primary health-care clinics. They were interviewed and screened for HIV and STIs. There was a significant decrease in HIV prevalence (11.5-6.9%). The decline was greatest among women aged 15-24 years. Syphilis, trichomoniasis, bacterial vaginosis, genital ulcers and reported STI symptoms also decreased significantly over the three-year inter-survey period. The proportion of women reporting casual sex decreased and knowledge of STI symptoms and health-care seeking behaviour improved. Herpes simplex virus type 2, genital warts, age at sexual debut, age at first pregnancy and condom use remained unchanged. In conclusion, decline in curable STIs and casual sex partners may partly explain the observed decline in HIV seroprevalence. Both STIs and sexual behaviour should be monitored in HIV sentinel surveillance. There remains a gap between knowledge of preventive behaviour and actual preventive practices.

Uganda's HIV/AIDS Epidemic: Guest Editorial

Uganda's HIV/AIDS Epidemic: Guest Editorial

Model Projections on the Required Coverage of Syringe Distribution to Prevent HIV Epidemics Among Injecting Drug Users

Although syringe distribution is effective in preventing HIV transmission among injecting drug users (IDUs), there is little evidence on the required coverage to substantially reduce HIV transmission. A mathematical model is developed to explore the relationship between the endemic HIV prevalence among IDUs and the coverage of syringe distribution. Data from IDU populations in the United Kingdom and Belarus are used to explore the implications of increasing coverage and the effect of changes in other behaviors. Projections suggest that there is a coverage threshold, which, if reached, could lead to substantial decreases in HIV prevalence. The threshold largely depends on the frequency that IDUs inject and (safely) reuse their syringes, and corresponds to less than 4 syringe-sharing events per IDU per month. Other factors, such as the injecting cessation rate and efficacy of syringe cleaning, only have substantial impact near threshold coverage levels. Our results support a policy of increasing the coverage of syringe distribution but highlight the difficulty in producing a universal coverage target. Great public health benefit could be conferred by encouraging the safe reuse of an IDU's own syringes and small stable injecting groups. Policies that discourage this will negate the impact of syringe distribution interventions.

Trends in HIV prevalence among white and African-American civilian applicants for United States Military Service, 1985 to 2003.

Data from 5,699,590 white and African-American civilian applicants who applied for service in the US military between 1985 and 2003 were used to analyze HIV prevalence trends. The overall HIV prevalence was 0.72/1000, which declined from 2.63/1000 in 1985 to 0.29/1000 in 1995, after which it remained stable until 2003 (0.30/1000). Larger and more significant declines in annual HIV prevalences were observed among the 4.5 million white applicants (-15.7% per year) compared with the 1.2 million African-American applicants (-10.0% per year). The HIV prevalence decline was also greater among male applicants (-12.4% per year) than female applicants (-7.1% per year). In the most recent 4 years study period, HIV prevalences increased among white applicants 25 to 29 years of age among African-American applicants 30 years of age or older. These data suggest that despite the overall consistent decreases in HIV prevalence from the 1980s to the late 1990s, an increase in HIV prevalence has taken place older African-American and white subgroups in more recent years.

HIV prevalence and trends from data in Zimbabwe, 1997–2004

Background: This paper brings together data from a variety of reports to provide a basis for assessing future steps for responding to and monitoring the HIV epidemic in Zimbabwe. Method:...

Urging others to be healthy: "intravention" by injection drug users as a community prevention goal.

"Intravention," prevention activities that are conducted by and sustained through ongoing actions of members of communities-at-risk, is an appropriate goal for HIV intervention activities. Data from 120 injection drug users in a Brooklyn, New York, neighborhood that has seen decreases in HIV prevalence among IDUs and little HIV diffusion to young adults indicate that most of them have recently (3 months) urged other people to engage in one or more self-protective actions. These data suggest that the common image of IDUs as simply being sources of social and medical problems is inaccurate. Research is needed into how to create and diffuse "communities of intravention; " and we suggest that behavioral interventions be evaluated for their success or failure at creating outward-focused health communication by participants as well as for their impact on individual risk behaviors.

Sentinel surveillance of HIV infection in HIV test clinics, Spain 1992-2002.

HIV infection in Spain was monitored in persons undergoing voluntary HIV testing in ten sentinel clinics between 1992 and 2002. Only patients on their first visit were considered for inclusion, and their numbers rose from 4426 in 1992 to 6649 in 2002. Most of them recognised their risk exposure as heterosexual. The proportion of injecting drug users decreased from 19% to 2% of the study population, and the proportion of female sex workers increased from 6% to 26%. The number of patients diagnosed with HIV infection declined from 604 in 1992 to 153 in 2002, and HIV prevalence fell from 13.6% to 2.3% in the same period. In all risk exposure categories, a decrease in HIV prevalence was observed, more pronounced during the first few years and stabilised in the later years. In 2002, the highest HIV prevalence was found in injecting drug users (IDUs) (14.2%), homo/bisexual men (7.5%) and individuals who had an HIV infected heterosexual partner (10.2%).

Educational attainment and HIV-1 infection in developing countries: a systematic review.

To assess whether educational status is associated with HIV-1 infection in developing countries by conducting a systematic review of published literature. Articles were identified through electronic databases and hand searching key journals. Studies containing appropriately analysed individual level data on the association between educational attainment and HIV-1 status in general population groups were included. Twenty-seven articles with appropriately analysed results from general population groups in developing countries were identified, providing information on only six countries. Large studies in four areas in Africa showed an increased risk of HIV-1 infection among the more educated, whilst among 21-year-old Thai army conscripts, longer duration of schooling was strongly protective against HIV infection. The association between education and schooling in Africa was stronger in rural areas and in older cohorts, but was similar in men and women. Serial prevalence studies showed little change in the association between schooling and HIV over time in Tanzania, but greater decreases in HIV prevalence among the more educated in Uganda, Zambia and Thailand. In Africa, higher educational attainment is often associated with a greater risk of HIV infection. However, the pattern of new HIV infections may be changing towards a greater burden among less educated groups. In Thailand those with more schooling remain at lower risk of HIV infection.

Spread of HIV infection in a rural area of Tanzania.

To assess the spread of HIV into rural areas. Since 1994 a demographic surveillance system (with 5-monthly rounds) and open adult cohort study have been established in a rural ward in Tanzania. Two sero-surveys of all resident adults aged 15-44 and 15-46 years were conducted in 1994 1995 and 1996-1997 respectively. Qualitative data were collected on mobility, bars and commercial sex. Attendance of the two rounds of survey was 5820 (78%) and 6413 (80%) in 1994/1995 and 1996/1997 respectively. HIV prevalence increased from 5.8% to 6.6%. HIV incidence was 0.73 and 0.84 per 100 person years among men and women respectively. HIV incidence under the age of 20 years was low among both sexes. Striking differences in HIV prevalence and incidence were observed within the small geographic area studied: HIV prevalence in the trading center was twice that in the area surrounding the trading center (within 2 km) and three to four times that in the rural villages (within 8 km of the trading center). Aggregate level data showed significant differences between the trading center and nearby rural villages in terms of sexual behavior, commercial sex workers, mobility of the population, and alcohol use. This study documents the existence of very substantial HIV prevalence and incidence differences within a small geographic rural area. The rapid decrease in HIV prevalence within a small rural area emphasizes the importance of concentrating HIV prevention efforts on high transmission areas, such as trading centers, especially in resource-poor settings. Furthermore, this has considerable implications for monitoring the spread of HIV through sentinel sites, as such sites are typically located in high transmission areas.