Errors in ‘BED’-Derived Estimates of HIV Incidence Will Vary by Place, Time and Age

The BED Capture Enzyme Immunoassay, believed to distinguish recent HIV infections, is being used to estimate HIV incidence, although an important property of the test--how specificity changes with time since infection--has not been not measured.We construct hypothetical scenarios for the performance of BED test, consistent with current knowledge, and explore how this could influence errors in BED estimates of incidence using a mathematical model of six African countries. The model is also used to determine the conditions and the sample sizes required for the BED test to reliably detect trends in HIV incidence.If the chance of misclassification by BED increases with time since infection, the overall proportion of individuals misclassified could vary widely between countries, over time, and across age-groups, in a manner determined by the historic course of the epidemic and the age-pattern of incidence. Under some circumstances, changes in BED estimates over time can approximately track actual changes in incidence, but large sample sizes (50,000+) will be required for recorded changes to be statistically significant.The relationship between BED test specificity and time since infection has not been fully measured, but, if it decreases, errors in estimates of incidence could vary by place, time and age-group. This means that post-assay adjustment procedures using parameters from different populations or at different times may not be valid. Further research is urgently needed into the properties of the BED test, and the rate of misclassification in a wide range of populations

Decline in HIV Prevalence among Young Women in Zambia: National-Level Estimates of Trends Mask Geographical and Socio-Demographic Differences

Background: A decline in HIV incidence has been reported in Zambia and a number of other sub-Saharan countries. The trend of HIV prevalence among young people is a good marker of HIV incidence. In this study, different data sources are used to examine geographical and sub-population group differentials in HIV prevalence trends among men and women aged 15–24 years in Zambia. Design and Methods: We analysed ANC data for women aged 15–24 years from 22 sentinel sites consistently covered in the period 1994–2008, and HIV data for young men and women aged 15–24 years from the ZDHS 2001/2 and 2007. In addition, we systematically reviewed peer-reviewed articles that have reported findings on HIV prevalence and incidence among young people. Findings: Overall trends of the ANC surveillance data indicated a substantial HIV prevalence decline among young women in both urban and rural areas. However, provincial declines differed substantially, i.e. between 10 % and 68 % among urban women, and from stability to 86 % among rural women. Prevalence declines were steeper among those with the highest educational attainments than among the least educated. The ZDHS data indicated a significant reduction in prevalence between the two survey rounds among young women only. Provincial-level ZDHS changes were difficult to assess because the sample sizes were small. ANC-based trend patterns were consistent with those observed in PMTCT-based data (2002

Impact of five years of peer-mediated interventions on sexual behavior and sexually transmitted infections among female sex workers in Mombasa, Kenya

<p>Abstract</p> <p>Background</p> <p>Since 2000, peer-mediated interventions among female sex workers (FSW) in Mombasa Kenya have promoted behavioural change through improving knowledge, attitudes and awareness of HIV serostatus, and aimed to prevent HIV and other sexually transmitted infection (STI) by facilitating early STI treatment. Impact of these interventions was evaluated among those who attended peer education and at the FSW population level.</p> <p>Methods</p> <p>A pre-intervention survey in 2000, recruited 503 FSW using snowball sampling. Thereafter, peer educators provided STI/HIV education, condoms, and facilitated HIV testing, treatment and care services. In 2005, data were collected using identical survey methods, allowing comparison with historical controls, and between FSW who had or had not received peer interventions.</p> <p>Results</p> <p>Over five years, sex work became predominately a full-time activity, with increased mean sexual partners (2.8 versus 4.9/week; <it>P </it>< 0.001). Consistent condom use with clients increased from 28.8% (145/503) to 70.4% (356/506; <it>P </it>< 0.001) as well as the likelihood of refusing clients who were unwilling to use condoms (OR = 4.9, 95%CI = 3.7–6.6). In 2005, FSW who received peer interventions (28.7%, 145/506), had more consistent condom use with clients compared with unexposed FSW (86.2% versus 64.0%; AOR = 3.6, 95%CI = 2.1–6.1). These differences were larger among FSW with greater peer-intervention exposure. HIV prevalence was 25% (17/69) in FSW attending ≥ 4 peer-education sessions, compared with 34% (25/73) in those attending 1–3 sessions (P = 0.21). Overall HIV prevalence was 30.6 (151/493) in 2000 and 33.3% (166/498) in 2005 (<it>P </it>= 0.36).</p> <p>Conclusion</p> <p>Peer-mediated interventions were associated with an increase in protected sex. Though peer-mediated interventions remain important, higher coverage is needed and more efficacious interventions to reduce overall vulnerability and risk.</p

Prevalence and risk factors for HIV-1 infection in rural Kilimanjaro region of Tanzania: Implications for prevention and treatment

BACKGROUND: Variability in stages of the HIV-1 epidemic and hence HIV-1 prevalence exists in different areas in sub-Saharan Africa. The purpose of this study was to investigate the magnitude of HIV-1 infection and identify HIV-1 risk factors that may help to develop preventive strategies in rural Kilimanjaro, Tanzania. METHODS: A cross-sectional study was conducted between March and May of 2005 involving all individuals aged between 15–44 years having an address in Oria Village. All eligible individuals were registered and invited to participate. Participants were interviewed regarding their demographic characteristics, sexual behaviors, and medical history. Following a pre-test counseling, participants were offered an HIV test. RESULTS: Of the 2 093 eligible individuals, 1 528 (73.0%) participated. The overall age and sex adjusted HIV-1 prevalence was 5.6%. Women had 2.5 times higher prevalence (8.0% vs. 3.2%) as compared to men. The age group 25–44 years, marriage, separation and low education were associated with higher risk of HIV-1 infection for both sexes. HIV-1 infection was significantly associated with >2 sexual partners in the past 12 months (women: Adjusted odds ratio [AOR], 2.5 (95%CI: 1.3–4.7), and past 5 years, [(men: AOR, 2.2 (95%CI:1.2–5.6); women: AOR, 2.5 (95%CI: 1.4–4.0)], unprotected casual sex (men: AOR,1.8 95%CI: 1.2–5.8), bottled alcohol (Men: AOR, 5.9 (95%CI:1.7–20.1) and local brew (men: AOR, 3.7 (95%CI: 1.5–9.2). Other factors included treatment for genital ulcers and genital discharge in the past 1 month. Health-related complaints were more common among HIV-1 seropositive as compared to seronegative participants and predicted the presence of HIV-1 infection. CONCLUSION: HIV-1 infection was highly prevalent in this population. As compared to our previous findings, a shift of the epidemic from a younger to an older age group and from educated to uneducated individuals was observed. Women and married or separated individuals remained at higher risk of infection. To prevent further escalation of the HIV epidemic, efforts to scale up HIV prevention programmes addressing females, people with low education, lower age at marriage, alcohol consumption, condom use and multiple sexual partners for all age groups remains a top priority. Care and treatment are urgently needed for those infected in rural areas

Lost opportunities in HIV prevention: programmes miss places where exposures are highest

Background: Efforts at HIV prevention that focus on high risk places might be more effective and less stigmatizing than those targeting high risk groups. The objective of the present study was to assess risk behaviour patterns, signs of current preventive interventions and apparent gaps in places where the risk of HIV transmission is high and in communities with high HIV prevalence. Methods: The PLACE method was used to collect data. Inhabitants of selected communities in Lusaka and Livingstone were interviewed about where people met new sexual partners. Signs of HIV preventive activities in these places were recorded. At selected venues, people were interviewed about their sexual behaviour. Peer educators and staff of NGOs were also interviewed. Results: The places identified were mostly bars, restaurants or sherbeens, and fewer than 20% reported any HIV preventive activity such as meetings, pamphlets or posters. In 43% of places in Livingstone and 26% in Lusaka, condoms were never available. There were few active peer educators. Among the 432 persons in Lusaka and 676 in Livingstone who were invited for interview about sexual behaviour, consistent condom use was relatively high in Lusaka (77%) but low in Livingstone (44% of men and 34% of women). Having no condom available was the most common reason for not using one. Condom use in Livingstone was higher among individuals socializing in places where condoms always were available. Conclusion: In the places studied we found a high prevalence of behaviours with a high potential for HIV transmission but few signs of HIV preventive interventions. Covering the gaps in prevention in these high exposure places should be given the highest priority

Evidence for population level declines in adult HIV prevalence in Kenya

The HIV/AIDS epidemic in Kenya has been tracked through annual sentinel surveillance in antenatal clinics since 1990. The system started with 13 sites and now has over 35. Behaviours have been measured through national Demographic and Health Surveys in 1993, 1998, and 2003. The surveillance data indicate that prevalence has declined substantially starting in 1998 in five of the original 13 sites and starting in 2000 in another four sites. No decline is evident in the other five original sites although the 2004 estimate is the lowest recorded. Nationally, adult prevalence has declined from 10% in the late 1990s to under 7% today. Surveys indicate that both age at first sex and use of condoms are rising and that the percentage of adults with multiple partners is falling. It is clear that HIV prevalence is now declining in Kenya in a pattern similar to that seen in Uganda but seven or eight years later. Although the coverage of preventive interventions has expanded rapidly since 2000 this expansion was too late to account for the beginnings of the decline in prevalence. More work is needed to understand fully the causes of this decline, but it is encouraging to see Kenya join the small list of countries experiencing significant declines in HIV prevalence