49 research outputs found
Delivery strategies for malaria vaccination in areas with seasonal malaria transmission
BACKGROUND: Seasonal vaccination with the RTS,S/AS01E malaria vaccine given alongside seasonal malaria chemoprevention (SMC) substantially reduces malaria in young children. The WHO has recommended the use of RTS,S/AS01E, including seasonal vaccination, in areas with seasonal malaria transmission. This study aimed to identify potential strategies to deliver RTS,S/AS01E, and assess the considerations and recommendations for delivery of seasonal malaria vaccination in Mali, a country with highly seasonal malaria. METHODS: Potential delivery strategies for RTS,S/AS01E in areas with seasonal malaria were identified through a series of high level discussions with the RTS,S/AS01E plus SMC trial investigators, international and national immunisation and malaria experts, and through the development of a theory of change. These were explored through qualitative in-depth interviews with 108 participants, including national-level, regional-level and district-level malaria and immunisation programme managers, health workers, caregivers of children under 5âyears of age, and community stakeholders. A national-level workshop was held to confirm the qualitative findings and work towards consensus on an appropriate strategy. RESULTS: Four delivery strategies were identified: age-based vaccination delivered via the Essential Programme on Immunisation (EPI); seasonal vaccination via EPI mass vaccination campaigns (MVCs); a combination of age-based priming vaccination doses delivered via the EPI clinics and seasonal booster doses delivered via MVCs; and a combination of age-based priming vaccination doses and seasonal booster doses, all delivered via the EPI clinics, which was the preferred strategy for delivery of RTS,S/AS01E in Mali identified during the national workshop. Participants recommended that supportive interventions, including communications and mobilisation, would be needed for this strategy to achieve required coverage. CONCLUSIONS: Four delivery strategies were identified for administration of RTS,S/AS01E alongside SMC in countries with seasonal malaria transmission. Components of these delivery strategies were defined as the vaccination schedule, and the delivery system(s) plus the supportive interventions needed for the strategies to be effective. Further implementation research and evaluation is needed to explore how, where, when and what effective coverage is achievable via these new strategies and their supportive interventions
Stakeholder engagement in the development of genetically modified mosquitoes for malaria control in West Africa: lessons learned from 10 years of Target Malariaâs work in Mali
From 2012 to 2023, the Malaria Research and Training Center (MRTC), based out of the University of Sciences, Techniques and Technologies of Bamako (USTTB), was part of the Target Malaria research consortium working towards developing novel gene drive-based tools for controlling populations of malaria vector mosquitoes. As part of this work, Target Malaria Mali has undertaken a range of in-depth engagement activities with the communities where their research is conducted and with other stakeholders nationally. These activities were meant to ensure that the projectâs activities took place with the agreement of those communities, and that those communities were able to play a role in shaping the projectâs approach to ensure that its eventual outcomes were in line with their needs and concerns. This paper aims to conduct a critical assessment of those 10Â years of stakeholder engagement in order to identify good practices which can inform future engagement work on gene drive research in West Africa. It sets out a range of approaches and practices that enabled the Target Malaria Mali team to engage a variety of stakeholders, to share information, collect feedback, and determine community agreement, in a manner that was inclusive, effective, and culturally appropriate. These can be useful tools for those working on gene drive research and other area-wide vector control methods in West African contexts to ensure that their research is aligned with the interests of the communities who are intended to be its ultimate beneficiaries, and to allow those communities to play a meaningful role in the research process
12-month mortality and loss-to-program in antiretroviral-treated children: The IeDEA pediatric West African Database to evaluate AIDS (pWADA), 2000-2008
<p>Abstract</p> <p>Background</p> <p>The IeDEA West Africa Pediatric Working Group (pWADA) was established in January 2007 to study the care and treatment of HIV-infected children in this region. We describe here the characteristics at antiretroviral treatment (ART) initiation and study the 12-month mortality and loss-to-program of HIV-infected children followed in ART programs in West Africa.</p> <p>Methods</p> <p>Standardized data from HIV-infected children followed-up in ART programs were included. Nine clinical centers from six countries contributed to the dataset (Benin, CĂŽte d'Ivoire, Gambia, Ghana, Mali and Senegal). Inclusion criteria were the followings: age 0-15 years and initiated triple antiretroviral drug regimens. Baseline time was the date of ART initiation. WHO criteria was used to define severe immunosuppression based on CD4 count by age or CD4 percent < 15%. We estimated the 12-month Kaplan-Meier probabilities of mortality and loss-to-program (death or loss to follow-up > 6 months) after ART initiation and factors associated with these two outcomes.</p> <p>Results</p> <p>Between June 2000 and December 2007, 2170 children were included. Characteristics at ART initiation were the following: median age of 5 years (Interquartile range (IQR: 2-9) and median CD4 percentage of 13% (IQR: 7-19). The most frequent drug regimen consisted of two nucleoside reverse transcriptase inhibitors and one non-nucleoside reverse transcriptase inhibitors (62%). During the first 12 months, 169 (7.8%) children died and 461(21.2%) were lost-to-program. Overall, in HIV-infected children on ART, the 12-month probability of death was 8.3% (95% Confidence Interval (CI): 7.2-9.6%), and of loss-to-program was 23.1% (95% CI: 21.3-25.0%). Both mortality and loss-to program were associated with advanced clinical stage, CD4 percentage < 15% at ART initiation and year (> 2005) of ART initiation.</p> <p>Conclusion</p> <p>Innovative and sustainable approaches are needed to better document causes of death and increase retention in HIV pediatric clinics in West Africa.</p
The Prevalence of Trachomatous Trichiasis in People Aged 15 Years and Over in Six Evaluation Units of Gaoual, Labé, Dalaba and Beyla Districts, Guinea.
PURPOSE: Trachoma is a public health problem in 42 countries. Inflammation associated with repeated ocular infection with Chlamydia trachomatis can cause the eyelid to scar and turn inwards, resulting in the eyelashes rubbing against the eyeball, known as trachomatous trichiasis (TT). In Guinea, baseline surveys conducted in 2013 reported inflammatory trachoma prevalences below the World Health Organization (WHO) threshold for elimination, but TT prevalences above threshold. Given this epidemiological context and time since baseline survey, TT-only surveys were conducted in selected districts to determine current TT prevalence. The results of this study provide critical data for assessing Guinea's achievement of trachoma elimination targets. METHODS: Four health districts, consisting of six evaluation units (EU), were surveyed. In each EU, field teams visited 29 clusters with a minimum 30 households included in each. Participants agedâ„15âyears were examined by certified graders trained to identify TT and determine whether management had been offered. RESULTS: A total of 22,476 people were examined, with 48 TT cases across the six EUs identified. Five of six EUs had an age-and-gender adjusted TT-prevalence unknown to the health system less than 0.2%, whereas one EU, Beyla 2, had an adjusted TT prevalence of 0.24%. CONCLUSION: These TT-only surveys, along with findings from other trachoma interventions, suggest that Guinea is close to achieving elimination of trachoma as a public health problem. This study demonstrates the value of undertaking TT-only surveys in settings where baseline surveys indicated active trachoma prevalences below WHO elimination threshold, but TT prevalences above it
HIV Status Disclosure and Retention in Care in HIV-Infected Adolescents on Antiretroviral Therapy (ART) in West Africa
We assessed the effect of HIV status disclosure on retention in care from initiation of antiretroviral therapy (ART) among HIV-infected children aged 10 years or more in Cote d'Ivoire, Mali and SĂ©nĂ©gal.Multi-centre cohort study within five paediatric clinics participating in the IeDEA West Africa collaboration. HIV-infected patients were included in this study if they met the following inclusion criteria: aged 10-21 years while on ART; having initiated ART â„ 200 days before the closure date of the clinic database; followed â„ 15 days from ART initiation in clinics with â„ 10 adolescents enrolled. Routine follow-up data were merged with those collected through a standardized ad hoc questionnaire on awareness of HIV status. Probability of retention (no death or loss-to-follow-up) was estimated with Kaplan-Meier method. Cox proportional hazard model with date of ART initiation as origin and a delayed entry at date of 10th birthday was used to identify factors associated with death or loss-to-follow-up.650 adolescents were available for this analysis. Characteristics at ART initiation were: median age of 10.4 years; median CD4 count of 224 cells/mmÂł (47% with severe immunosuppression), 48% CDC stage C/WHO stage 3/4. The median follow-up on ART after the age of 10 was 23.3 months; 187 adolescents (28.8%) knew their HIV status. The overall probability of retention at 36 months after ART initiation was 74.6% (95% confidence interval [CI]: 70.5-79.0) and was higher for those disclosed compared to those not: adjusted hazard ratio for the risk of being death or loss-to-follow-upâ=â0.23 (95% CI: 0.13-0.39).About 2/3 of HIV-infected adolescents on ART were not aware of their HIV status in these ART clinics in West Africa but disclosed HIV status improved retention in care. The disclosure process should be thus systematically encouraged and organized in adolescent populations
Long-term cellular immunity of vaccines for Zaire Ebola Virus Diseases
Recent Ebola outbreaks underscore the importance of continuous prevention and disease control efforts. Authorized vaccines include Merckâs Ervebo (rVSV-ZEBOV) and Johnson & Johnsonâs two-dose combination (Ad26.ZEBOV/MVA-BN-Filo). Here, in a five-year follow-up of the PREVAC randomized trial (NCT02876328), we report the results of the immunology ancillary study of the trial. The primary endpoint is to evaluate long-term memory T-cell responses induced by three vaccine regimens: Ad26âMVA, rVSV, and rVSVâbooster. Polyfunctional EBOV-specific CD4+ T-cell responses increase after Ad26 priming and are further boosted by MVA, whereas minimal responses are observed in the rVSV groups, declining after one year. In-vitro expansion for eight days show sustained EBOV-specific T-cell responses for up to 60 months post-prime vaccination with both Ad26-MVA and rVSV, with no decline. Cytokine production analysis identify shared biomarkers between the Ad26-MVA and rVSV groups. In secondary endpoint, we observed an elevation of pro-inflammatory cytokines at Day 7 in the rVSV group. Finally, we establish a correlation between EBOV-specific T-cell responses and anti-EBOV IgG responses. Our findings can guide booster vaccination recommendations and help identify populations likely to benefit from revaccination
Amélioration de la méthode d'échantillonnage en deux cycles et application à l'estimation du total de la population
L'analyse des données dans des populations de tailles finies utilise les méthodes d'échantillonnage. Lorsque nous sommes en présence de données qui sont recueillies à diverses périodes dans le temps, une méthode que l'on peut privilégier est la méthode d'échantillonnage en deux cycles. Ce mémoire propose une amélioration de la méthode d'échantillonnage en deux cycles basée sur l'exploitation de la technique de sélection avec probabilités proportionnelles à la taille. AprÚs avoir introduit les méthodes classiques d'échantillonnage, nous décrirons en détail le plan d'échantillonnage en deux cycles et nous l'appliquerons à un ensemble de données agricoles
Amélioration de la méthode d'échantillonnage en deux cycles et application à l'estimation du total de la population
L'analyse des données dans des populations de tailles finies utilise les méthodes d'échantillonnage. Lorsque nous sommes en présence de données qui sont recueillies à diverses périodes dans le temps, une méthode que l'on peut privilégier est la méthode d'échantillonnage en deux cycles. Ce mémoire propose une amélioration de la méthode d'échantillonnage en deux cycles basée sur l'exploitation de la technique de sélection avec probabilités proportionnelles à la taille. AprÚs avoir introduit les méthodes classiques d'échantillonnage, nous décrirons en détail le plan d'échantillonnage en deux cycles et nous l'appliquerons à un ensemble de données agricoles
Evaluation of a Nutritional Support Intervention in Malnourished HIV-Infected Children in Bamako, Mali
International audienceBackground: We assessed a nutritional support intervention in malnourished HIV-infected children in a HIV-care program of the University Hospital Gabriel TourĂ©, Bamako, Mali. Methods: All HIV-infected children younger than 15 years were diagnosed for malnutrition between 07 and 12, 2014. Malnutrition was defined according to the WHO growth standards with Z-scores. Two types were studied: acute malnutrition (AM) and chronic malnutrition (CM). All participants were enrolled in a 6-month prospective interventional cohort, receiving Ready-To-Use Therapeutic Food, according to type of malnutrition. The nutritional intervention was offered until child growth reached â1.5 SD threshold. Six-month probability to catch up growth (>â2 SD) was assessed for AM using Kaplan-Meier curves and Cox model. Results: Among the 348 children screened, 198 (57%) were malnourished of whom 158 (80%) children were included: 97 (61%) for AM (35 with associated CM) and 61 (39%) with CM. Fifty-nine percent were boys, 97% were on antiretroviral therapy, median age was 9.5 years (Interquartile Range: 6.7â12.3). Among children with AM, 74% catch-up their growth at 6-month; probability to catch-up growth was greater for those without associated CM (adjusted Hazard Ratio = 1.97, CI 95%: 1.13 to 3.44). Anemia decreased significantly from 40% to 12% at the end of intervention ( P < 0.001). Conclusions: This macronutrient intervention showed 6-month benefits for weight gain and reduced anemia among these children mainly on antiretroviral therapy for years and aged greater than 5 years at inclusion. Associated CM slows down AM recovery and needs longer support. Integration of nutritional screening and care in the pediatric HIV-care package is needed to optimize growth and prevent metabolic disorders
Production and sensory evaluation of composite breads based on wheat and whole millet or sorghum in the presence of Weissella confusa A16 exopolysaccharides
The aim of the study was to evaluate the acceptability of composite breads based on local cereal (millet and sorghum) formulations. Bread preparations based on 50% wheat flour and 50% local cereal flour were made in the presence of exopolysaccharide (Eps) production stimulated by a strain of Weissella confusa A16 in the fermented dough. Seven formulations were done in two baking sets and were submitted to sensory evaluations which consisted of tests on sensory profile, hedonic analysis and ranking. Results showed that the presence of Eps improved the acceptability of breads made with local cereal flours. The white color of the crumb of breads made with 100% wheat flour was the most appreciated by consumers. The less local flour is used in the bread preparation, the better the bread is appreciated. Nevertheless, formulations containing whole grains were the least appreciated, partly because of the hardness of the breads. Interestingly, more than 50% of consumers found the taste pleasant for breads made with 50% millet flour.Peer reviewe