Household and individual level factors associated with HIV infection in KwaZulu-Natal

MSc (Med) Population-Based Field Epidemiology, Faculty of Health Sciences, University of the Witwatersrand, 2009Background: Sub-Saharan Africa continues to bear the brunt of the global HIV epidemic, with the epicentre located in Southern Africa. Of all the adult and children living with HIV globally in 2006, two-thirds (63%) were in sub-Saharan Africa.1 The epicenter of the HIV/AIDS epidemic in South Africa is located in the KwaZulu Natal province, where HIV incidence and prevalence continue to remain high and this has serious implications for HIV prevention and control programmes. Objectives i. To profile individuals who sero-converted during the period 2003-2007 in order to better target interventions. ii. To estimate the incidence rate for HIV during the period 2003 to 2007. iii. To identify factors associated with HIV infection at individual and household levels in Kwazulu-Natal. Methods This involved analysis data of a dynamic cohort study. The follow-up period was 2003-2007, and the study was a household-based HIV sero-prevalence survey of a population in Kwazulu Natal, South Africa, conducted by the Africa Centre for Health and Population Studies. The cohort comprised females aged 15 to 49 and males 15 to 54 years who participated in the baseline HIV sero-prevalence survey in 2003 and/ or subsequent surveys in 2005, 2006 and 2007. Individuals who participated in at least two surveys and had a negative HIV result on first enrolment were included in the analysis. Selected demographic, socio-economic, behavioural and geographic variables of the participants were obtained from the demographic surveillance system (DSS) database of the Africa Centre Demographic and Information System (ACDIS) for analysis. Profiles of recently HIV sero-converters were based on these variables and descriptive statistics used to compare the differences in sero-conversion between the different strata of each variable. Multiple logistic regression was used to investigate the association between variables of key interest. Results A total of 39, 738 individuals were surveyed for the four annual sero-prevalence surveys conducted from 2003-2007. Of these, 41.5% (n=16,491) were HIV negative on their first enrolment into the study, 11.6% (n=4610) were HIV positive on first enrolment, while 46.9% (n=18,637) had either participated in just one out of the four surveys, or were non-resident at baseline. These two categories of participants as well as those who tested HIV positive on first enrolment were dropped from the analysis. The final sample size used for analysis was 16,491 individuals and comprised 8,425(51.1%) females aged 15-49 years old and 8,066 (48.9%) males aged 15-54 years old. The incidence rate for HIV sero-conversion among the 16, 491 individuals included in the final analysis was 11.5 per 1000PYs during the follow-up period. In other words, 539 individuals sero-converted during 46818.15 person-years (PYs) at risk from 2003-2007. A significant proportion of the new HIV acquisitions (69.8%) occurred in households without any recently or previously infected household member, and women had a significantly greater risk of HIV infection(IR= 16.9 per 1000PYs; 95% CI: 15.33-18.640) compared to men(IR=5.9; 95% CI: 4.95-6.94) in this study area. Conclusion The younger age bracket (24-30 years old) was associated with significantly higher risk of HIV infection compared to the older age category. However, the age group 20-24 years bears the greatest burden of HIV pandemic in this community. Majority of seroconverters were rural dwellers but peri-urban dwellers had the greatest risk of HIV acquisition. The study also showed that attendance of a school or a training facility on a full-time basis during the follow-up period was protective for HIV acquisition compared. Also, attainment of standard 10 to 12 level of education was associated with a greater risk of HIV seroconversion. This can be attributed to the age of individuals at these levels of education and the associated high risk profile of this group. Living in close proximity to primary or secondary roads was also associated with a risk of HIV infection compared to those living far from major roads. This could be due to the ease of mobility and potential exposure multiple sex partners. This may be due to a desire for modern social amenities which requires financial wherewithal, which in turn facilitates transactional sex

A phase 2b randomized, controlled trial of the efficacy of the GMZ2 malaria vaccine in African children.

BACKGROUND: GMZ2 is a recombinant protein malaria vaccine, comprising two blood-stage antigens of Plasmodium falciparum, glutamate-rich protein and merozoite surface protein 3. We assessed efficacy of GMZ2 in children in Burkina Faso, Gabon, Ghana and Uganda. METHODS: Children 12-60months old were randomized to receive three injections of either 100μg GMZ2 adjuvanted with aluminum hydroxide or a control vaccine (rabies) four weeks apart and were followed up for six months to measure the incidence of malaria defined as fever or history of fever and a parasite density ⩾5000/μL. RESULTS: A cohort of 1849 children were randomized, 1735 received three doses of vaccine (868 GMZ2, 867 control-vaccine). There were 641 malaria episodes in the GMZ2/Alum group and 720 in the control group. In the ATP analysis, vaccine efficacy (VE), adjusted for age and site was 14% (95% confidence interval [CI]: 3.6%, 23%, p-value=0.009). In the ITT analysis, age-adjusted VE was 11.3% (95% CI 2.5%, 19%, p-value=0.013). VE was higher in older children. In GMZ2-vaccinated children, the incidence of malaria decreased with increasing vaccine-induced anti-GMZ2 IgG concentration. There were 32 cases of severe malaria (18 in the rabies vaccine group and 14 in the GMZ2 group), VE 27% (95% CI -44%, 63%). CONCLUSIONS: GMZ2 is the first blood-stage malaria vaccine to be evaluated in a large multicenter trial. GMZ2 was well tolerated and immunogenic, and reduced the incidence of malaria, but efficacy would need to be substantially improved, using a more immunogenic formulation, for the vaccine to have a public health role

Indoor residual spraying with a non-pyrethroid insecticide reduces the reservoir of <i>Plasmodium falciparum</i> in a high-transmission area in northern Ghana

High-malaria burden countries in sub-Saharan Africa are shifting from malaria control towards elimination. Hence, there is need to gain a contemporary understanding of how indoor residual spraying (IRS) with non-pyrethroid insecticides when combined with long-lasting insecticidal nets (LLINs) impregnated with pyrethroid insecticides, contribute to the efforts of National Malaria Control Programmes to interrupt transmission and reduce the reservoir of Plasmodium falciparum infections across all ages. Using an interrupted time-series study design, four age-stratified malariometric surveys, each of ~2,000 participants, were undertaken pre- and post-IRS in Bongo District, Ghana. Following the application of three-rounds of IRS, P. falciparum transmission intensity declined, as measured by a >90% reduction in the monthly entomological inoculation rate. This decline was accompanied by reductions in parasitological parameters, with participants of all ages being significantly less likely to harbor P. falciparum infections at the end of the wet season post-IRS (aOR = 0.22 [95% CI: 0.19–0.26], p-value < 0.001). In addition, multiplicity of infection (MOIvar) was measured using a parasite fingerprinting tool, designed to capture within-host genome diversity. At the end of the wet season post-IRS, the prevalence of multi-genome infections declined from 75.6% to 54.1%. This study demonstrates that in areas characterized by high seasonal malaria transmission, IRS in combination with LLINs can significantly reduce the reservoir of P. falciparum infection. Nonetheless despite this success, 41.6% of the population, especially older children and adolescents, still harboured multi-genome infections. Given the persistence of this diverse reservoir across all ages, these data highlight the importance of sustaining vector control in combination with targeted chemotherapy to move high-transmission settings towards pre-elimination. This study also points to the benefits of molecular surveillance to ensure that incremental achievements are not lost and that the goals advocated for in the WHO’s High Burden to High Impact strategy are realized

Can we measure cognitive constructs consistently within and across cultures? Evidence from a test battery in Bangladesh, Ghana, and Tanzania.

We developed a test battery for use among children in Bangladesh, Ghana, and Tanzania, assessing general intelligence, executive functioning, and school achievement. The instruments were drawn from previously published materials and tests. The instruments were adapted and translated in a systematic way to meet the needs of the three assessment contexts. The instruments were administered by a total of 43 trained assessors to 786 children in Bangladesh, Ghana, and Tanzania with a mean age of about 13 years (range: 7-18 years). The battery provides a psychometrically solid basis for evaluating intervention studies in multiple settings. Within-group variation was adequate in each group. The expected positive correlations between test performance and age were found and reliability indices yielded adequate values. A confirmatory factor analysis (not including the literacy and numeracy tests) showed a good fit for a model, merging the intelligence and executive tests in a single factor labeled general intelligence. Measurement weights invariance was found, supporting conceptual equivalence across the three country groups, but not supporting full score comparability across the three countries

Can we measure cognitive constructs consistently within and across cultures? Evidence from a test battery in Bangladesh, Ghana, and Tanzania

We developed a test battery for use among children in Bangladesh, Ghana, and Tanzania, assessing general intelligence, executive functioning, and school achievement. The instruments were drawn from previously published materials and tests. The instruments were adapted and translated in a systematic way to meet the needs of the three assessment contexts. The instruments were administered by a total of 43 trained assessors to 786 children in Bangladesh, Ghana, and Tanzania with a mean age of about 13 years (range: 7–18 years). The battery provides a psychometrically solid basis for evaluating intervention studies in multiple settings. Within-group variation was adequate in each group. The expected positive correlations between test performance and age were found and reliability indices yielded adequate values. A confirmatory factor analysis (not including the literacy and numeracy tests) showed a good fit for a model, merging the intelligence and executive tests in a single factor labeled general intelligence. Measurement weights invariance was found, supporting conceptual equivalence across the three country groups, but not supporting full score comparability across the three countries