Agence de Médecine Préventive

Flexible grid topology has become a key enabler of flexibility in modern power grids, particularly for congestion management. Studying the effects of combinatorial topological changes is therefore of significant interest, though this remains computationally intensive in most cases. To address this, we revisit the superposition theorem, which has served as the foundation for the decomposition of numerous power system problems over the past decades, particularly those involving changes in generation and loads. However, its application has traditionally been restricted to fixed grid topologies, breaking down as soon as a topological change occurs. In this paper, we extend the superposition theorem to accommodate varying grid topologies by leveraging well-known distribution factors. This unified framework applies to all types of topological changes, including line disconnection and reconnection, as well as bus splitting and merging. We provide numerical experiments to validate our approach and highlight its advantages in terms of speed-up and interpretability. Finally, we demonstrate its application in two key use cases: remedial action search and updated security analysis following a topological change. Our results show more than an order-of-magnitude speed-up for real-sized grids compared to the fastest power flow solvers.

Abstract Introduction The burden of morbidity and mortality from severe pneumonia remains high among children under five, particularly in resource-limited countries such as Burkina Faso. Targeted hospital-based interventions are essential to achieve Sustainable Development Goal 3.2, which aims to reduce under-five mortality to 25 deaths per 1,000 live births by 2030. Methods A prospective cohort study was conducted in the pediatrics department of Regional Referral Hospital of Banfora, including 1,406 children aged 2–59 months hospitalized for severe pneumonia between August 2021 and January 2024. Predictors of mortality were identified using the Fine and Gray competing risk model. Results A total of 1,406 children were included in the analysis. The median age was 18 months (interquartile range: 9–32 months), and 53% were male. During hospitalization, 8.96% (126/1,406; 95% CI: 7.58–10.57) died, corresponding to a mortality rate of 1.93 per 100 person-days. Age < 12 months doubled the instantaneous risk of death. Additionally, hypoxemia (SaO₂ < 90%) (adjusted subdistribution hazard ratio [aSHR]: 1.54; 95% CI: 1.02–2.32), hospitalization during the rainy season (aSHR: 1.73; 95% CI: 1.18–2.54), convulsions (aSHR: 2.93; 95% CI: 1.92–4.47), the presence of stridor (aSHR: 2.17; 95% CI: 1.46–3.22), and hypoglycemia (aSHR: 2.37; 95% CI: 1.45–3.88) increased the risk of death. However, the risk of death was significantly lower in children with moderate or severe anaemia (respectively aSHR = 0.45; 95% CI: 0.24 - 0.84 and aSHR = 0.26; 95% CI: 0.13 - 0.52) and having received antibiotic therapy (ceftriaxone alone [SHRa = 0.52; 95% CI: 0.30 - 0.90] or combined with gentamicin (SHRa = 0.45; 95% CI: 0.30-0.69); ampicillin [aSHR = 0,35; IC95%: 0,13-0,97] and ampicillin combined with gentamicin (SHRa = 0.43; CI: 0.20 - 0.95). Conclusion The incidence and in-hospital mortality of severe pneumonia are a cause for concern at the Regional Referral Hospital of Banfora and in Burkina Faso. Targeted interventions in hospital settings are necessary and can help achieve Sustainable Development Goal 3.2 on reducing under-five mortality to 25 deaths per 1,000 live births by 2030.

RésuméIntroductionLa Direction de la vaccination et logistique du Bénin a commandité cette étude afin de disposer de données factuelles pour améliorer la performance du Programme élargi de vaccination. Les objectifs étaient de recenser les acteurs de la vaccination, décrire leur profil, leur répartition géographique et déterminer leurs besoins de formation.MéthodesEn décembre 2020, nous avons recensé les acteurs de la vaccination via leurs dossiers administratifs et des entretiens téléphoniques. Les données étaient collectées dans chaque direction départementale et zone sanitaire par des points focaux à l'aide d'une grille Excel®.RésultatsNous avons recensé 3 893 acteurs de la vaccination, âgés en moyenne de 39 ans dont 66% de femmes, 53% d'aides-soignants, 77% de vaccinateurs et 56% d'agents contractuels de l’État. Environ 96% d'entre eux exerçaient dans les centres périphériques, 56% n’étaient pas formés et 14% l’étaient depuis plus de 5 ans. Plus de la moitié des acteurs n’étaient pas formés pour leur fonction. Nous avons estimé à 70% la proportion d'acteurs à former, alors que 98% des acteurs souhaitaient être formés notamment en vaccination (74%), gestion des vaccins (69%), chaîne du froid (61%), surveillance des maladies (61%) et maintenance (47%).ConclusionLa prédominance des aides-soignants et des femmes et la faible proportion de formés parmi les acteurs de la vaccination, étaient également observées dans d'autres pays d'Afrique subsaharienne. Le Bénin devra mobiliser des ressources suffisantes pour renforcer les capacités techniques des acteurs de la vaccination.

ABSTRACT Introduction There is a dearth of literature on vaccine hesitancy in Africa. In this study, we aimed to explore the drivers of hesitancy toward recommended childhood vaccines in Kenya, Malawi, and Ethiopia. Methods A scoping review methodology was used as this evidence synthesis approach is suitable for mapping existing literature and identifying knowledge gaps. For this study, we systematically searched four electronic databases for published and unpublished literature from the three African countries. The methodological framework that was used is in line with Arksey and O’Malley’s recommendations as modified by Levac. Results A total of 23 publications met the inclusion criteria and were included in the study. Majority of the studies were published after 2012. In these three African countries, hesitancy toward recommended childhood vaccines is driven by a mix of caregiver-related factors, health systems-related factors as well as the influence of community context. Conclusion This study demonstrated that vaccine hesitancy in Kenya, Malawi, and Ethiopia is a complex phenomenon that is driven by multiple interrelated and interconnected factors.

ObjectiveTo evaluate vaccination coverage, identify reasons for non-vaccination and assess satisfaction with two innovative strategies for distributing second doses in an oral cholera vaccine campaign in 2016 in Lake Chilwa, Malawi, in response to a cholera outbreak.MethodsWe performed a two-stage cluster survey. The population interviewed was divided in three strata according to the second-dose vaccine distribution strategy: (i) a standard strategy in 1477 individuals (68 clusters of 5 households) on the lake shores; (ii) a simplified cold-chain strategy in 1153 individuals (59 clusters of 5 households) on islands in the lake; and (iii) an out-of-cold-chain strategy in 295 fishermen (46 clusters of 5 to 15 fishermen) in floating homes, called zimboweras.FindingVaccination coverage with at least one dose was 79.5% (1153/1451) on the lake shores, 99.3% (1098/1106) on the islands and 84.7% (200/236) on zimboweras. Coverage with two doses was 53.0% (769/1451), 91.1% (1010/1106) and 78.8% (186/236), in the three strata, respectively. The most common reason for non-vaccination was absence from home during the campaign. Most interviewees liked the novel distribution strategies.ConclusionVaccination coverage on the shores of Lake Chilwa was moderately high and the innovative distribution strategies tailored to people living on the lake provided adequate coverage, even among hard-to-reach communities. Community engagement and simplified delivery procedures were critical for success. Off-label, out-of-cold-chain administration of oral cholera vaccine should be considered as an effective strategy for achieving high coverage in hard-to-reach communities. Nevertheless, coverage and effectiveness must be monitored over the short and long term.

PROFESSOR DOUTOR ILÍDIO DO AMARAL

BackgroundCholera is endemic in Guinea, having suffered consecutive outbreaks from 2004 to 2008 followed by a lull until the 2012 epidemic. Here we describe the temporal-spatial and behavioural characteristics of cholera cases in Conakry during a three-year period, including the large-scale 2012 epidemic.MethodsWe used the national and African Cholera Surveillance Network (Africhol) surveillance data collected from every cholera treatment centre in Conakry city from August 2011 to December 2013. The prevalence of suspect and confirmed cholera cases, the case fatality ratio (CFR), and the factors associated with suspected cholera were described according to three periods: pre-epidemic (A), epidemic 2012 (B) and post epidemic (C). Weekly attack rates and temporal-spatial clustering were calculated at municipality level for period B. Cholera was confirmed by culture at the cholera national reference laboratory.ResultsA total of 4559 suspect cases were reported: 66, 4437, and 66 suspect cases in periods A, B and C, respectively. Among the 204 suspect cases with culture results available, 6%, 60%, and 70% were confirmed in periods A, B, and C, respectively. With 0.3%, the CFR was significantly lower in period B than in periods A (7.6%) and C (7.1%). The overall attack rate was 0.28% in period B, ranging from 0.17% to 0.31% across municipalities. Concomitantly, a cluster of cases was identified in two districts in the northern part of Conakry. At 14%, rice water stools were less frequent in period A than in period B and C (78% and 84%). Dehydration (31% vs 94% and 89%) and coma (0.4% vs 3.1% and 2.9%) were lower during period B than in periods A and C. The treatment of drinking water was less frequent in period A, while there were more reports of recent travel in period C.ConclusionsThe epidemic dynamic and the sociological description of suspect cases before, during, and after the large-scale epidemic revealed that the Vibrio cholerae was already present before the epidemic. However, it appeared that infected individuals reacted differently in terms of disease severity as well as their access to treated water and travel habits. Such an in-depth description of cholera epidemics should be systematically carried out in cholera endemic settings in order to prioritize higher risk areas, identify transmission factors, and optimize preventive interventions.