Prevalence and determinants of breast cancer screening in four sub-Saharan African countries: a population-based study.

OBJECTIVES: Breast cancer is the most prevalent cancer and the second leading cause of cancer-related deaths among women after cervical cancer in much of sub-Saharan Africa. This study aims to examine the prevalence and sociodemographic-socioeconomic factors associated with breast cancer screening among women of reproductive age in sub-Saharan Africa. DESIGN: A weighted population-based cross-sectional study using Demographic and Health Surveys (DHS) data. We used all available data on breast cancer screening from the DHS for four sub-Saharan African countries (Burkina Faso, Ivory Coast, Kenya and Namibia). Breast cancer screening was the outcome of interest for this study. Multivariable Poisson regression was used to identify independent factors associated with breast cancer screening. SETTING: Four countries participating in the DHS from 2010 to 2014 with data on breast cancer screening. PARTICIPANTS: Women of reproductive age 15-49 years (N=39 646). RESULTS: The overall prevalence of breast cancer screening was only 12.9% during the study period, ranging from 5.2% in Ivory Coast to 23.1% in Namibia. Factors associated with breast cancer screening were secondary/higher education with adjusted prevalence ratio (adjusted PR)=2.33 (95% CI: 2.05 to 2.66) compared with no education; older participants, 35-49 years (adjusted PR=1.73, 95% CI : 1.56 to 1.91) compared with younger participants 15-24 years; health insurance coverage (adjusted PR=1.57, 95% CI: 1.47 to 1.68) compared with those with no health insurance and highest socioeconomic status (adjusted PR=1.33, 95% CI : 1.19 to 1.49) compared with lowest socioeconomic status. CONCLUSION: Despite high breast cancer mortality rates in sub-Saharan Africa, the prevalence of breast cancer screening is substantially low and varies gradually across countries and in relation to factors such as education, age, health insurance coverage and household wealth index level. These results highlight the need for increased efforts to improve the uptake of breast cancer screening in sub-Saharan Africa.

Longitudinal analysis of gamma delta T cell subsets during malaria infections in Malian adults.

BACKGROUND: Immunity that limits malarial disease is acquired over time, but adults living in endemic areas continue to become infected and can require treatment for clinical illness. Gamma delta (γδ) T cells, particularly the Vδ2+ subset, have been associated with development of clinical malaria in children. In this study, the dynamics of total γδ T cells, Vδ2+ and Vδ2- T cells were measured during a malaria transmission season in Malian adults. METHODS: This study explored γδ T cell dynamics and Plasmodium falciparum infection outcomes over the course of the malaria transmission season in Malian adults enrolled in the placebo arm of a double-blind randomized vaccine trial. All volunteers were treated with anti-malarial drugs prior to the start of the transmission season and blood smears were assessed for P. falciparum infection every 2 weeks from July 2014 to January 2015. The study participants were stratified as either asymptomatic infections or clinical malaria cases. Vδ2+ and Vδ2- γδ T cell frequencies and activation (as measured by CD38 expression) were measured in all study participants at baseline and then every 2 months using a whole blood flow cytometry assay. RESULTS: Forty of the forty-three subjects became infected with P. falciparum and, of those, 21 individuals were diagnosed with clinical malaria at least once during the season. The γδ T cell percentage and activation increased over the duration of the transmission season. Both the Vδ2+ and Vδ2- γδ T cells were activated by P. falciparum infection. CONCLUSION: γδ T cells increased during a malaria transmission season and this expansion was noted in both the Vδ2+ and Vδ2- γδ T cells. However, neither expansion or activation of either γδ T cell subsets discriminated study participants that had asymptomatic infections from those that had clinical malaria cases.

Exclusive breastfeeding promotion and neuropsychological outcomes in 5-8 year old children from Uganda and Burkina Faso: Results from the PROMISE EBF cluster randomized trial.

BACKGROUND: The beneficial effects from exclusive breastfeeding (EBF) have been widely acknowledged. We assessed the effect of exclusive breastfeeding promotion by peer counsellors in Uganda and Burkina Faso, on cognitive abilities, social emotional development, school performance and linear growth among 5-8 years old children. METHODS: Children in the PROMISE EBF trial (2006-2008) were re-enrolled in the follow-up PROMISE Saving Brains (SB) study (2013-2015). Caretaker interviews captured sociodemographic characteristics and social emotional development using the parent version of the Strengths and Difficulties Questionnaire (SDQ). Overall cognition and working memory were assessed using the Kaufman Assessment Battery for Children, second edition (KABC2), cognitive flexibility was measured with the Child Category Test (CCT), and attention with the Test of Variables of Attention (T.O.V.A), while school performance was measured by a standardized test on arithmetic and reading. Country-pooled, age adjusted z-scores from each of the above outcomes were entered into a linear regression model controlling for confounders. RESULTS: The number of children re-enrolled in the intervention and control arms were: 274/396 (69.2%) and 256/369 (69.4%) in Uganda and 265/392 (67.6%) and 288/402 (71.6%) in Burkina Faso. Assessment of cognitive ability showed small and no significant differences, of which general cognition (z-scores, 95% CI) showed the largest mean difference: -0.17 (-0.40; 0.05). Social emotional symptoms were similar across arms. There were no differences in school performance or linear growth for age detected. CONCLUSION: Peer promotion for exclusive breastfeeding in Burkina Faso and Uganda was not associated with differences at 5-8 years of age in a range of measures of child development: cognitive abilities, emotion-behaviour-social symptoms or linear growth. This study from sub Saharan Africa did not reconfirm findings elsewhere that have shown an association between exclusive breastfeeding and cognitive performance. This might be due to a number of methodological limitations inherent in the current study. For example since the majority of the children were breastfed, the benefits of the intervention could have been diluted. Other factors such as the mental and HIV status of the mothers (which were not assessed in the current study) could have affected our results. Hence regarding the effect of exclusive breastfeeding on measures of child neurocognitive development in sub Saharan Africa, the jury is still out. TRIAL REGISTRATION: ClinicalTrials.gov NCT01882335.

γδ T Cells Are Required for the Induction of Sterile Immunity during Irradiated Sporozoite Vaccinations.

Whole-sporozoite vaccines confer sterilizing immunity to malaria-naive individuals by unknown mechanisms. In the first PfSPZ Vaccine trial ever in a malaria-endemic population, Vδ2 γδ T cells were significantly elevated and Vγ9/Vδ2 transcripts ranked as the most upregulated in vaccinees who were protected from Plasmodium falciparum infection. In a mouse model, absence of γδ T cells during vaccination impaired protective CD8 T cell responses and ablated sterile protection. γδ T cells were not required for circumsporozoite protein-specific Ab responses, and γδ T cell depletion before infectious challenge did not ablate protection. γδ T cells alone were insufficient to induce protection and required the presence of CD8α+ dendritic cells. In the absence of γδ T cells, CD8α+ dendritic cells did not accumulate in the livers of vaccinated mice. Altogether, our results show that γδ T cells were essential for the induction of sterile immunity during whole-organism vaccination.

Safety and efficacy of PfSPZ Vaccine against Plasmodium falciparum via direct venous inoculation in healthy malaria-exposed adults in Mali: a randomised, double-blind phase 1 trial.

BACKGROUND: Plasmodium falciparum sporozite (PfSPZ) Vaccine is a metabolically active, non-replicating, whole malaria sporozoite vaccine that has been reported to be safe and protective against P falciparum controlled human malaria infection in malaria-naive individuals. We aimed to assess the safety and protective efficacy of PfSPZ Vaccine against naturally acquired P falciparum in malaria-experienced adults in Mali. METHODS: After an open-label dose-escalation study in a pilot safety cohort, we did a double-blind, randomised, placebo-controlled trial based in Donéguébougou and surrounding villages in Mali. We recruited 18-35-year-old healthy adults who were randomly assigned (1:1) in a double-blind manner, with stratification by village and block randomisation, to receive either five doses of 2·7 × 105 PfSPZ or normal saline at days 0, 28, 56, 84, and 140 during the dry season (January to July inclusive). Participants and investigators were masked to group assignments, which were unmasked at the final study visit, 6 months after receipt of the last vaccination. Participants received combined artemether and lumefantrine (four tablets, each containing 20 mg artemether and 120 mg lumefantrine, given twice per day over 3 days for a total of six doses) to eliminate P falciparum before the first and last vaccinations. We collected blood smears every 2 weeks and during any illness for 24 weeks after the fifth vaccination. The primary outcome was the safety and tolerability of the vaccine, assessed as local and systemic reactogenicity and adverse events. The sample size was calculated for the exploratory efficacy endpoint of time to first P falciparum infection beginning 28 days after the fifth vaccination. The safety analysis included all participants who received at least one dose of investigational product, whereas the efficacy analyses included only participants who received all five vaccinations. This trial is registered at ClinicalTrials.gov, number NCT01988636. FINDINGS: Between Jan 18 and Feb 24, 2014, we enrolled 93 participants into the main study cohort with 46 participants assigned PfSPZ Vaccine and 47 assigned placebo, all of whom were evaluable for safety. We detected no significant differences in local or systemic adverse events or laboratory abnormalities between the PfSPZ Vaccine and placebo groups, and only grade 1 (mild) local or systemic adverse events occurred in both groups. The most common solicited systemic adverse event in the vaccine and placebo groups was headache (three [7%] people in the vaccine group vs four [9%] in the placebo group) followed by fatigue (one [2%] person in the placebo group), fever (one [2%] person in the placebo group), and myalgia (one [2%] person in each group). The exploratory efficacy analysis included 41 participants from the vaccine group and 40 from the placebo group. Of these participants, 37 (93%) from the placebo group and 27 (66%) from the vaccine group developed P falciparum infection. The hazard ratio for vaccine efficacy was 0·517 (95% CI 0·313-0·856) by time-to-infection analysis (log-rank p=0·01), and 0·712 (0·528-0·918) by proportional analysis (p=0·006). INTERPRETATION: PfSPZ Vaccine was well tolerated and safe. PfSPZ Vaccine showed significant protection in African adults against P falciparum infection throughout an entire malaria season. FUNDING: US National Institutes of Health Intramural Research Program, Sanaria.

Knops blood group polymorphism and susceptibility to Mycobacterium tuberculosis infection.

BACKGROUND: Complement receptor 1 (CR1) protein carries the Knops blood group antigens and is the receptor for the major ligand involved in Mycobacterium tuberculosis (Mtb) adhesion to macrophages. Erythrocyte CR1 binds immune complexes (ICs) formed during Mtb invasion, facilitating their clearance by the host immune system. The occurrence of specific Knops blood group genotypes among African populations was investigated to evaluate their impact on resistance or susceptibility to Mtb infection. STUDY DESIGN AND METHODS: The distribution of the Knops blood group genotypes (McC and Sl) was compared between tuberculosis (TB) patients with confirmed diagnosis of Mtb in isolates and negative controls. Conditional logistic regression was used to access the association between genotypes distribution and susceptibility to Mtb infection. RESULTS: At the McC locus, individuals heterozygous (McC(a) /McC(b) ) were more resistant to Mtb infection (odds ratio [OR], 0.42; 95% confidence interval [CI], 0.22-0.81; p = 0.007). Although less significant, a similar effect was conferred by Sl1/Sl2 genotype (OR, 0.05; 95% CI, 0.28-0.9; p = 0.02). This protective effect was maintained among individuals presenting the McC(b) /Sl2 haplotype (OR, 0.25; 95% CI, 0.08-0.74; p = 0.008). CONCLUSION: Acquisition of McC(b) and Sl2 alleles among African population is correlated with resistance to Mtb infection, adding this bacterium to the list of mechanisms underlying the selection of the Knops blood group polymorphism among these populations.