Caroline Jeffery

New evidence on the HIV epidemic in Libya: why countries must implement prevention programs among people who inject drugs.

Background:Libya had one of the worlds largest nosocomial HIV outbreaks in the late 1990s leading to the detention of 6 foreign medical workers. They were released in 2007 after the Libyan Government and the European Union agreed to humanitarian cooperation that included the development of Libyas first National HIV Strategy and the research reported in this article. Despite the absence of sound evidence on the status and dynamics of Libyas HIV epidemic, some officials posited that injecting drug use was the main mode of transmission. We therefore sought to assess HIV prevalence and related risk factors among people who inject drugs (PWID) in Tripoli. Methods:We conducted a cross-sectional survey among 328 PWID in Tripoli using respondent-driven sampling. We collected behavioral data and blood samples for HIV, hepatitis C virus, and hepatitis B virus testing. Results:We estimate an HIV prevalence of 87%, hepatitis C virus prevalence of 94%, and hepatitis B virus prevalence of 5%. We detected injecting drug use–related and sexual risk factors in the context of poor access to comprehensive services for HIV prevention and mitigation. For example, most respondents (85%) reported having shared needles. Conclusions:In this first biobehavioral survey among PWID in Libya, we detected one of the highest (or even the highest) levels of HIV infection worldwide in the absence of a comprehensive harm-reduction program. There is an urgent need to implement an effective National HIV Strategy informed by the results of this research, especially because recent military events and related sociopolitical disruption and migration might lead to a further expansion of the epidemic.

Identifying multidrug resistant tuberculosis transmission hotspots using routinely collected data

In most countries with large drug resistant tuberculosis epidemics, only those cases that are at highest risk of having MDRTB receive a drug sensitivity test (DST) at the time of diagnosis. Because of this prioritized testing, identification of MDRTB transmission hotspots in communities where TB cases do not receive DST is challenging, as any observed aggregation of MDRTB may reflect systematic differences in how testing is distributed in communities. We introduce a new disease mapping method, which estimates this missing information through probability-weighted locations, to identify geographic areas of increased risk of MDRTB transmission. We apply this method to routinely collected data from two districts in Lima, Peru over three consecutive years. This method identifies an area in the eastern part of Lima where previously untreated cases have increased risk of MDRTB. This may indicate an area of increased transmission of drug resistant disease, a finding that may otherwise have been missed by routine analysis of programmatic data. The risk of MDR among retreatment cases is also highest in these probable transmission hotspots, though a high level of MDR among retreatment cases is present throughout the study area. Identifying potential multidrug resistant tuberculosis (MDRTB) transmission hotspots may allow for targeted investigation and deployment of resources.

Putting the C back into the ABCs: a multi-year, multi-region investigation of condom use by Ugandan youths 2003-2010.

A major strategy for preventing transmission of HIV and other STIs is the consistent use of condoms during sexual intercourse. Condom use among youths is particularly important to reduce the number of new cases and the national prevalence. Condom use has been often promoted by the Uganda National AIDS Commission. Although a number of studies have established an association between condom use at one’s sexual debut and future condom use, few studies have explored this association over time, and whether the results are generalizable across multiple locations. This multi time point, multi district study assesses the relationship between sexual debut and condom use and consistent use of condoms thereafter. Uganda has used Lot Quality Assurance Sampling surveys since 2003 to monitor district level HIV programs and improve access to HIV health services. This study includes 4518 sexually active youths interviewed at five time points (2003–2010) in up to 23 districts located across Uganda. Using logistic regression, we measured the association of condom use at first sexual intercourse on recent condom usage, controlling for several factors including: age, sex, education, marital status, age at first intercourse, geographical location, and survey year. The odds of condom use at last intercourse, using a condom at last intercourse with a non-regular partner, and consistently using a condom are, respectively, 9.63 (95%WaldCI = 8.03–11.56), 3.48 (95%WaldCI = 2.27–5.33), and 11.12 (95%WaldCI = 8.95–13.81) times more likely for those individuals using condoms during their sexual debut. These values did not decrease by more than 20% when controlling for potential confounders. The results suggest that HIV prevention programs should encourage condom use among youth during sexual debut. Success with this outcome may have a lasting influence on preventing HIV and other STIs later in life.

Filling the Knowledge Gap: Measuring HIV Prevalence and Risk Factors among Men Who Have Sex with Men and Female Sex Workers in Tripoli, Libya

Background Publications on Libya’s HIV epidemic mostly examined the victims of the tragic nosocomial HIV outbreak in the 1990s and the related dispute about the detention of foreign medical workers. The dispute resolution in 2003 included an agreement with the European Union on humanitarian cooperation and the development of Libya’s first National HIV Strategy. As part of this we conducted Libya’s first bio-behavioural survey among men having sex with men (MSM) and female sex workers (FSW). Methods Using respondent-driven sampling, we conducted a cross-sectional study to estimate the prevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and related risk factors among 227 MSM and 69 FSW in Tripoli (FSW recruitment ended prematurely due to the political events in 2011). Results For MSM we estimated an HIV prevalence of 3.1%, HBV prevalence of 2.9%, and HCV prevalence of 7.3%, and for FSW an HIV prevalence of 15.7%, HBV prevalence of 0%, and HCV prevalence of 5.2%. We detected high levels of risk behaviours, poor HIV-related knowledge, high stigma and lack of prevention programmes. These results must be interpreted in the context of the political situation which prohibited reaching an ideal sample size for FSW. Conclusion There is urgent need to implement an effective National HIV Strategy informed by the results of this research. The risk of transmission within different risk groups and to the general population may be high given the recent military events that led to increased violence, migration, and the disruption of essential HIV-related services.

The effect of spatial aggregation on performance when mapping a risk of disease

BackgroundSpatial data on cases are available either in point form (e.g. longitude/latitude), or aggregated by an administrative region (e.g. zip code or census tract). Statistical methods for spatial data may accommodate either form of data, however the spatial aggregation can affect their performance. Previous work has studied the effect of spatial aggregation on cluster detection methods. Here we consider geographic health data at different levels of spatial resolution, to study the effect of spatial aggregation on disease mapping performance in locating subregions of increased disease risk.MethodsWe implemented a non-parametric disease distance-based mapping (DBM) method to produce a smooth map from spatially aggregated childhood leukaemia data. We then simulated spatial data under controlled conditions to study the effect of spatial aggregation on its performance. We used an evaluation method based on ROC curves to compare performance of DBM across different geographic scales.ResultsApplication of DBM to the leukaemia data illustrates the method as a useful visualization tool. Spatial aggregation produced expected degradation of disease mapping performance. Characteristics of this degradation, however, varied depending on the interaction between the geographic extent of the higher risk area and the level of aggregation. For example, higher risk areas dispersed across several units did not suffer as greatly from aggregation. The choice of centroids also had an impact on the resulting mapping.ConclusionsDBM can be implemented for continuous and discrete spatial data, but the resulting mapping can lose accuracy in the second setting. Investigation of the simulations suggests a complex relationship between performance loss, geographic extent of spatial disturbances and centroid locations. Aggregation of spatial data destroys information and thus impedes efforts to monitor these data for spatial disturbances. The effect of spatial aggregation on cluster detection, disease mapping, and other useful methods in spatial epidemiology is complex and deserves further study.

Access to Education for Orphans and Vulnerable Children in Uganda: A Multi-District, Cross-Sectional Study Using Lot Quality Assurance Sampling from 2011 to 2013

Objectives This study estimates the proportion of Orphans and Vulnerable Children (OVC) attending school in 89 districts of Uganda from 2011 – 2013 and investigates the factors influencing OVC access to education among this population. Methods This study used secondary survey data from OVCs aged 5 – 17 years, collected using Lot Quality Assurance Sampling in 87 Ugandan districts over a 3-year period (2011 – 2013). Estimates of OVC school attendance were determined for the yearly time periods. Logistic regression was used to investigate the factors influencing OVC access to education. Results 19,354 children aged 5-17 were included in the analysis. We estimated that 79.1% (95% CI: 78.5% – 79.7%) of OVCs attended school during the 3-year period. Logistic regression revealed the odds of attending school were lower among OVCs from Western (OR 0.88; 95% CI: 0.79 – 0.99) and Northern (OR 0.64; 95% CI: 0.56 – 0.73) regions compared to the Central region. Female OVCs had a significantly higher odds of attending school (OR 1.09; 95% CI: 1.02 – 1.17) compared to their male counterparts. When adjusting for all variables simultaneously, we found the odds of school attendance reduced by 12% between 2011 and 2012 among all OVCs (OR 0.88; 95% CI: 0.81 – 0.97). Conclusion Our findings reinforce the need to provide continuing support to OVC in Uganda, ensuring they have the opportunity to attain an education. The data indicate important regional and gender variation that needs to be considered for support strategies and in social policy. The results suggest the need for greater local empowerment to address the needs of OVCs. We recommend further research to understand why OVC access to education and attendance varies between regions and improvement of district level mapping of OVC access to education, and further study to understand the particular factors impacting the lower school attendance of male OVCs.

Sexual and Reproductive Health Among Ugandan Youth: 2003-04 to 2012

PURPOSE Suboptimal sexual and reproductive health (SRH) increases morbidity, mortality, and gender inequity and slows development. In Uganda, youths represent 20% of the population, and the burden of sexually transmitted infections (STIs), including human immunodeficiency virus (HIV), is substantial. METHODS We analyzed survey data collected using the lot quality assurance sampling (LQAS) technique from two time periods, 2003-2004 and 2012. We assessed knowledge, behaviors, and access to SRH services of youths aged 15-24 years. Using logistic regression, we examined factors associated with these indicators. RESULTS All indicators have improved between the early and later time period. Youths knowing where to get HIV tests increased from <40% to 80% (both sexes); the number of youths reporting ever having an HIV test increased from 8% to 48% (males) and 10% to 64% (females). Knowledge of other STIs improved but remains low; only half of respondents know signs and symptoms of STIs, and less than half know what action to take when infected. In the late period, 85% of female youths, compared with 93% of males reported knowing where to obtain condoms. The proportion of youths reporting sexual debut before age 15 years decreased, less so for males than that for females. Increased age and level of education are associated with positive change for most indicators. CONCLUSIONS Over the last decade, progress has been made toward improving the SRH of young people in Uganda. Further efforts are required to ensure universal access and sufficient health education to facilitate the continued improvement of safe sexual behaviors among youth aged 15-24 years.

Attracting female sex workers to HIV testing and counselling in Ethiopia: a qualitative study with sex workers in Addis Ababa

Despite growing efforts to increase HIV testing and counselling (HTC) services for most at risk populations in Ethiopia, the use of these services by female sex workers (FSWs) remains low. With rising numbers of FSWs in Addis Ketema and concerns about their high risk behaviours, exploring and addressing the barriers to uptake is crucial. This qualitative study explores the barriers to utilising HTC facilities and identifies the motives and motivations of FSWs who seek HTC through in-depth and semi-structured interviews with female sex workers, healthcare workers and key informants. Results indicate that FSWs face numerous barriers including inability to seek treatment if found to be positive due to the requirement of an identity (ID) card many do not own. Many FSWs reported discriminatory behaviour from healthcare workers and a lack of dedicated services. What is clear from the findings is that distinct strategies, which differ from those of the broader population, are required to attract FSWs — strategies which take into account the barriers and maximise the reported motives and motivations for testing.

Comparing two survey methods of measuring health-related indicators: Lot Quality Assurance Sampling and Demographic Health Surveys

Two common methods used to measure indicators for health programme monitoring and evaluation are the demographic and health surveys (DHS) and lot quality assurance sampling (LQAS); each one has different strengths. We report on both methods when utilised in comparable situations.

Distance-based mapping of disease risk.

Abstract: In this article, we consider the problem of comparing the distribution of observations in a planar region to a pre-specified null distribution. Our motivation is a surveillance setting where we map locations of incident disease, aiming to monitor these data over time, to locate potential areas of high/low incidence so as to direct public health actions. We propose a non-parametric approach to distance-based disease risk mapping inspired by tomographic imaging. We consider several one-dimensional projections via the observed distribution of distances to a chosen fixed point; we then compare this distribution to that expected under the null and average these comparisons across projections to compute a relative-risk-like score at each point in the region. The null distribution can be established from historical data. Scores are displayed on the map using a color scale. In addition, we give a detailed description of the method along with some desirable theoretical properties. To further assess the performance of this method, we compare it to the widely used log ratio of kernel density estimates. As a performance metric, we evaluate the accuracy to locate simulated spatial clusters superimposed on a uniform distribution in the unit disk. Results suggest that both methods can adequately locate this increased risk but each relies on an appropriate choice of parameters. Our proposed method, distance-based mapping (DBM), can also generalize to arbitrary metric spaces and/or high-dimensional data.