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Résumé : La présente étude vise à présenter sociologiquement et linguistiquement une langue qui, jusqu’à présent n’a pas été étudiée : le gbandjé. En effet, cette langue, située au nord de la Côte d’Ivoire, à la frontière avec le Mali, fait partie des langues en danger et qui n’ont pas encore été l’objet d’une étude descriptive ou sociolinguistique. Une langue en danger dont la constitution des ressources documentaires s’avère capitale pour la recherche scientifique la préservation et la promotion de patrimoine linguistique et culturel de la Côte d’Ivoire. Mots-clés : Gbandjé, langue en danger, sociolinguistique, linguistique.

Introduction: Few studies on SARS-CoV-2 seroprevalence in Ivory Coast have been conducted since the first case was reported on March 11, 2020. The main objective of this study was to observe and better understand the circulation of SARS-CoV-2 in Abidjan. Methodology: This prospective study collected data concerning age, sex, vaccination status, municipality of origin, monthly income, frequency of malaria, and frequency of diarrheal diseases in persons who gave their informed consent. Venous blood samples were taken to test for anti- SARS-COV-2 antibodies (IgM and IgG) using the VIDAS automated system. Results: A total of 1504 patients were recruited and tested for antibodies directed against SARS-COV-2. Data analysis revealed the presence of anti-SARS-CoV-2 in 53.5% of participants, 17.3% of the participants had a previous symptomatic infection, 31.4% had an asymptomatic infection, and 44.8% were never in contact with the virus. Seroprevalence of SARS-CoV-2 was higher in Marcory (70.9%) and Cocody (61.1%) than in the remaining townships (48.4%). Township rates of serologically confirmed SARS-CoV-2 infection correlated with poverty index (p = 0.025), children < 5 years' proportion in the township (p = 0.026), and levels of malaria (p = 0.034). Conclusions: In the city of Abidjan, COVID-19 is strongly modulated by poverty, the proportion of babies and toddlers in the community, or exposure to malaria. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) infection is the tenth leading cause of death worldwide. Mother‐to‐child transmission of HBV occurring mainly at delivery remains one of the most common routes of infection in developing countries. One of the main challenges concerning HBV in Africa is to implement a prevention policy aiming at interrupting the cycle of pseudo‐vertical transmission of this infection. The aim of this study was to assess the implication of certain bacterial and viral factors in mother‐to‐child transmission of HBV. This prospective study was conducted on 165 pregnant women carriers of HBV surface antigen (HBsAg) and their 169 newborns who attended care at the Gynecology Department of the University Hospital of Cocody. Serological, molecular, and bacteriological analyses were performed on blood samples and vaginal secretions. Mean viral load (VL) was 4.5 ± 1.3 log10 IU/ml, while mean HBsAg titres were 3.5 ± 0.9 log10 IU/ml. HBV DNA was found in vaginal secretions in 13.3% of mothers and in the blood of 10.3% of the newborns. Six bacterial species were identified in the vaginal discharge of pregnant women during labour before delivery. Staphylococcus aureus and Enterococcus faecalis were the most frequent species found in 23.0% and 13.9% of cases. Mothers positive for vaginal HBV DNA displayed higher plasma HBV DNA loads than negative mothers (6.2 ± 1.6 log10 IU/ml vs. 4.3 ± 1.0 log10 IU/ml, p <.0001). In conclusion, our study showed that presence of HBV DNA in vaginal secretions and the presence of S. aureus could play a role in mother‐to‐child transmission of HBV. HBV DNA detection in vaginal discharge represents a promising biomarker to identify newborns at risk of perinatal persistent infection. [ABSTRACT FROM AUTHOR]

Background: Although most births in Mali occur in health facilities, a substantial number of newborns still die during delivery and within the first 7 days of life, mainly because of existing training deficiencies and the challenges of maintaining intrapartum and postpartum care skills. Objective: This trial aims to assess the effectiveness and cost-effectiveness of an intervention combining clinical audits and low-dose, high-frequency (LDHF) in-service training of health care providers and community health workers to reduce perinatal mortality. Methods: The study is a three-arm cluster randomized controlled trial in the Koulikoro region in Mali. The units of randomization are each of 84 primary care facilities. Each trial arm will include 28 facilities. The facilities in the first intervention arm will receive support in implementing mortality and morbidity audits, followed by one-day LDHF training biweekly, for 6 months. The health workers in the second intervention arm (28 facilities) will receive a refresher course in maternal neonatal and child health (MNCH) for 10 days in a classroom setting, in addition to mortality and morbidity audits and LDHF hands-on training for 6 months. The control arm, also with 28 facilities, will consist solely of the standard MNCH refresher training delivered in a classroom setting. The main outcomes are perinatal deaths in the intervention arms compared with those in the control arm. A final sample of approximately 600 deliveries per cluster was expected for a total of 30,000 newborns over 14 months. Data sources included both routine health records and follow-up household surveys of all women who recently gave birth in the study facility 7 days postdelivery. Data collection tools will capture perinatal deaths, complications, and adverse events, as well as the status of the newborn during the perinatal period. A full economic evaluation will be conducted to determine the incremental cost-effectiveness of each of the case-based focused LDHF hands-on training strategies in comparison to MNCH refresher training in a classroom setting. Results: The trial is complete. The recruitment began on July 15, 2019, and data collection began on July 23, 2019, and was completed in November 2020. Data cleaning or analyses began at the time of submission of the protocol. Conclusions: The results will provide policy makers and practitioners with crucial information on the impact of different health care provider training modalities on maternal and newborn health outcomes and how to successfully implement these strategies in resource-limited settings. [ABSTRACT FROM AUTHOR]

The 2014–2015 outbreak of Ebola Virus Disease (EVD) in West Africa was unprecedented in size and scope. The World Health Organization, government of Guinea and other partners undertook a field trial of efficacy of an Ebola vaccine in Guinea, with a parallel immunogenicity study in front-line workers. However, several obstacles had to be overcome. One was the need to teach Good Clinical Practices to a large group of field workers who had never participated in vaccine clinical trial research. Because the trial design was complex, performing this efficacy trial during an Ebola outbreak would have been challenging even for experienced investigators. For field workers who had never previously participated in a clinical trial, this constituted a daunting challenge. Another challenge was to provide independent monitoring to document the quality and validity of the field trial data to support future regulatory agency licensure. Here we discuss how these challenges were overcome, and what lessons can be drawn for the future. Intensive GCP was expeditiously arranged for 251 clinical study staff on-site in Guinea. The trials were initiated within days after completion of training. Monitoring (100% of participants in the efficacy trial and 50% in the immunogenicity trial) began at the onset of the trials. Early monitoring detected many minor errors but prompt feedback and guidance from the monitors, who explained the mistakes and proposed corrective actions, diminished error frequency as the trials progressed. Monitoring later in the trials showed what one would expect in a study conducted by experienced investigators. Should a vaccine field trial have to be hastily arranged during a future emerging disease outbreak in a developing country setting, our methods of training and monitoring could provide a model. [ABSTRACT FROM AUTHOR]

Background Few studies describe the respiratory syncytial virus (RSV) burden in African populations, and most have utilized hospital-based surveillance. In Mali, no community-based studies exist of the incidence or epidemiology of RSV infection. This study provides the first estimates of RSV incidence in Mali. Methods In a cohort of infants enrolled in a clinical trial of maternal influenza vaccination, we estimate incidence of RSV-associated febrile illness in the first 6 months of life and identify risk factors for RSV infection and progression to severe disease. Infants (N = 1871) were followed from birth to 6 months of age and visited weekly to detect pneumonia and influenza-like illness. Baseline covariates were explored as risk factors for RSV febrile illness and RSV pneumonia or hospitalization. Results Incidence of RSV illness was estimated at 536.8 per 1000 person-years, and 86% (131/153) of RSV illness episodes were positive for RSV-B. RSV illness was most frequent in the fifth month of life and associated with having older mothers and with lower parity. The incidence of RSV-associated hospitalizations was 45.6 per 1000 person-years. Among infants with RSV illness, males were more likely to be hospitalized. The incidence of RSV pneumonia was 29 cases per 1000 person-years. Conclusions In the first 6 months of life, Malian infants have a high incidence of RSV illness, primarily caused by RSV-B. Prevention of early RSV will require passive protection via maternal immunization in pregnancy. Mali is the first country where RSV-B has been identified as the dominant subtype, with potential implications for vaccine development. [ABSTRACT FROM AUTHOR]

Type-E hepatitis is responsible for more than three million symptomatic cases and more than 40,000 deaths worldwide. The situation of this hepatitis is overall poorly known in sub-Saharan Africa. Notably, the baseline circulation of HEV outside sporadic outbreaks has been barely characterized in this large region. More specifically, the impact of superinfection by this virus on the health status of the large reservoir of patients chronically infected with other hepatitis viruses remains to be evaluated. We searched for anti-HEV immunoglobulins in a series of 200 pregnant women and 92 patients with persistent liver infections with hepatitis B or C viruses and subsequently tried to assess serological co-variations with demographical and clinical features. We observed that only 1.5 % of expectant mothers were seropositive of anti-HEV IgG while it was the case for 18.4 % of patients with chronic liver diseases (P=4.5E-07). The presence of anti-HEV was not linked to any of the collected demographical features (age, sex, education, pork meat consumption, water supply, ...). By contrast, the presence of anti-HEV was significantly associated with increased levels (1.6-1.8-fold, P<0.0001) of blood aminotransferases (AST, ALT) in patients with persistent hepatitis B or C. Our work indicates that, in Ivory Coast, the presence of IgG directed against HEV might contribute to a deterioration of liver health in patients with already installed persistent liver infections. The mechanisms explaining such phenomenon at distance of acute phase of infection are still unknown but might be linked either to a residual persistence of HEV in a context of general immune exhaustion or to an inappropriate auto-immune reaction as already observed in the aftermath of other viral infection types. [ABSTRACT FROM AUTHOR]

In this paper, we extend the mathematical model framework of Dembele et al. (2009), and use it to study malaria disease transmission dynamics and control in irrigated and non-irrigated villages of Niono in Mali. In case studies, we use our "fftted" models to show that in support of the survey studies of Dolo et al., the female mosquito density in irrigated villages of Niono is much higher than that of the adjacent non-irrigated villages. Many parasitological surveys have observed higher incidence of malaria in non-irrigated villages than in adjacent irrigated areas. Our "fftted" models support these observations. That is, there are more malaria cases in non-irrigated areas than the adjacent irrigated villages of Niono. As in Chitnis et al., we use sensitivity analysis on the basic reproduction numbers in constant and periodic environments to study the impact of the model parameters on malaria control in both irrigated and non-irrigated villages of Niono. [ABSTRACT FROM AUTHOR]

Background: Maternal influenza immunization has gained traction as a strategy to diminish maternal and neonatal mortality. However, efforts to vaccinate pregnant women against influenza in developing countries will require substantial investment. We present cost-effectiveness estimates of maternal influenza immunization based on clinical trial data from Bamako, Mali. Methods: We parameterized a decision-tree model using prospectively collected trial data on influenza incidence, vaccine efficacy, and direct and indirect influenza-related healthcare expenditures. Since clinical trial participants likely had better access to care than the general Malian population, we also simulated scenarios with poor access to care, including decreased healthcare resource utilization and worse influenza-related outcomes. Results: Under base-case assumptions, a maternal influenza immunization program in Mali would cost $857 (95% UI: $188-$2358) per disability-adjusted life year (DALY) saved. Adjusting for poor access to care yielded a cost-effectiveness ratio of $486 (95% UI: $105-$1425) per DALY saved. Cost-effectiveness ratios were most sensitive to changes in the cost of a maternal vaccination program and to the proportion of laboratory-confirmed influenza among infants warranting hospitalization. Mean cost-effectiveness estimates fell below Mali’s GDP per capita when the cost per pregnant woman vaccinated was $1.00 or less with no adjustment for access to care or $1.67 for those with poor access to care. Healthcare expenditures for lab-confirmed influenza were not significantly different than the cost of influenza-like illness. Conclusions: Maternal influenza immunization in Mali would be cost-effective in most settings if vaccine can be obtained, managed, and administered for ≤$1.00 per pregnant woman. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a major public health concern in Sub-Saharan Africa. Early research in Ivory Coast showed that chronic hepatitis B and aflatoxin B1 exposure were the two most important etiological agents of HCC in the country but, surprisingly, no survey analyzing HCC etiologies has been conducted since decades. In a preliminary report, we characterized for hepatitis B and C markers 30 consecutive cases of HCC recruited from Abidjan hospitals between June 2011 and December 2012. Nutritional and lifestyle features of patients were analyzed as well. The mean age of the patients was 53 ± 15 years with a sex ratio (M:F = 2.7). HBsAg was the most frequent viral marker in the series (63 %). All HBV isolates belonged to genotype E. With regards to regional standard, anti-HCV reached a very high level (47 %) in the present series. Hepatitis C was more frequent among patients living outside Abidjan (83 vs 23 %, P = 0.009). Patients living in Abidjan were significantly younger than individual living elsewhere in the country (48 ± 14 vs 60 ± 16 years old, P = 0.038) reflecting a possible role for local environmental pollution in tumor progression. Finally, we observed that patients born in Mandé/Gur-speaking regions (North) were younger (48 ± 14 vs 59 ± 15, P = 0.05) and consumed maize more frequently (80 vs 26 %, P = 0.009) than other patients. Interestingly, maize consumption was associated with a trend for aminotransferases elevation (mean = 1.7-1.8 fold, P = 0.06) suggesting a direct hepatic toxicity of this staple food in Ivory Coast. In conclusion, our work indicates that HCC epidemiology underwent recently major drifts in Ivory Coast. [ABSTRACT FROM AUTHOR]

Background: Neglected tropical diseases are co-endemic in many areas of the world, including sub Saharan Africa. Currently lymphatic filariasis (albendazole/ivermectin) and trachoma (azithromycin) are treated separately. Consequently, financial and logistical benefit can be gained from integration of preventive chemotherapy programs in such areas. Methodology/Findings: 4 villages in two co-endemic districts (Kolondièba and Bougouni) of Sikasso, Mali, were randomly assigned to coadministered treatment (ivermectin/albendazole/azithromycin) or standard therapy (ivermectin/albendazole with azithromycin 1 week later). These villages had previously undergone 4 annual MDA campaigns with ivermectin/albendazole and 2 with azithromycin. One village was randomly assigned to each treatment arm in each district. There were 7515 eligible individuals in the 4 villages, 3011(40.1%) of whom participated in the study. No serious adverse events occurred, and the majority of adverse events were mild in intensity (mainly headache, abdominal pain, diarrhoea and "other signs/symptoms"). The median time to the onset of the first event, of any type, was later (8 days) in the two standard treatment villages than in the co-administration villages. Overall the number of subjects reporting any event was similar in the co-administration group compared to the standard treatment group [18.7% (281/1501) vs. 15.8% (239/1510)]. However, the event frequency was higher in the coadministration group (30.4%) than in the standard treatment group (11.0%) in Kolondièba, while the opposite was observed in Bougouni (7.1% and 20.9% respectively). Additionally, the overall frequency of adverse events in the co-administration group (18.7%) was comparable to or lower than published frequencies for ivermectin+albendazole alone. Conclusions: These data suggest that co-administration of ivermectin+albendazole and azithromycin is safe; however the small number of villages studied and the large differences between them resulted in an inability to calculate a meaningful overall estimate of the difference in adverse event rates between the regimens. Further work is therefore needed before co-administration can be definitively recommended. Trial Registration: ClinicalTrials.gov; NCT01586169 Author Summary: Neglected tropical diseases are co-endemic in many areas of the world. Currently lymphatic filariasis (albendazole+ivermectin) and trachoma (azithromycin) are treated separately. Benefits can be gained from integration of preventive chemotherapy programs in such areas. To assess the safety of this approach, 4 villages in two co-endemic districts in Mali were randomly assigned to coadministered treatment (ivermectin/albendazole/azithromycin) or standard therapy (ivermectin/albendazole with azithromycin 1 week later). One village was randomly assigned to each treatment in each district. 3011(40.1%) of 7515 eligible individuals in the 4 villages participated in the study. No serious adverse events occurred, and most events were mild in intensity (mainly headache, abdominal pain, and diarrhoea). Overall the number of subjects reporting any event was similar with co-administration compared to standard treatment [18.7% (281/1501) vs. 15.8% (239/1510)]. The overall frequency of adverse events with co-administration was comparable to or lower than published frequencies for ivermectin/albendazole alone. These data suggest that co-administration is safe; however the small number of villages studied and the large differences between them meant that a meaningful estimate of the differences could not be calculated, and further work will be needed before a recommendation can be made. [ABSTRACT FROM AUTHOR]

• New RSV prevention products can substantially reduce disease burden. • Longer-acting monoclonal antibodies, priced affordably, are likely cost-effective. • Maternal vaccines meeting preferred product characteristics would be cost-effective. • RSV prevention products can provide good value in low-income countries. Low- and middle-income countries have a high burden of respiratory syncytial virus lower respiratory tract infections. A monoclonal antibody administered monthly is licensed to prevent these infections, but it is cost-prohibitive for most low- and middle-income countries. Long-acting monoclonal antibodies and maternal vaccines against respiratory syncytial virus are under development. We estimated the likelihood of respiratory syncytial virus preventive interventions (current monoclonal antibody, long-acting monoclonal antibody, and maternal vaccine) being cost-effective in Mali. We modeled age-specific and season-specific risks of respiratory syncytial virus lower respiratory tract infections within monthly cohorts of infants from birth to six months. We parameterized with respiratory syncytial virus data from Malian cohort studies, as well as product efficacy from clinical trials. Integrating parameter uncertainty, we simulated health and economic outcomes for status quo without prevention, intra-seasonal monthly administration of licensed monoclonal antibody, pre-seasonal birth dose administration of a long-acting monoclonal antibody, and maternal vaccination. We then calculated the incremental cost-effectiveness ratio of each intervention compared to status quo from the perspectives of the government, donor, and society. At a price of $3 per dose and from the societal perspective, current monoclonal antibody, long-acting monoclonal antibody, and maternal vaccine would have incremental cost-effectiveness ratios of $4280 (95% CI $1892 to $122,434), $1656 (95% CI $734 to $9091), and $8020 (95% CI $3501 to $47,047) per disability-adjusted life-year averted, respectively. In Mali, long-acting monoclonal antibody is likely to be cost-effective from both the government and donor perspectives at $3 per dose. Maternal vaccine would need higher efficacy over that measured by a recent trial in order to be considered cost-effective. [ABSTRACT FROM AUTHOR]

Background: The 2014 west African Zaire Ebola virus epidemic prompted worldwide partners to accelerate clinical development of replication-defective chimpanzee adenovirus 3 vector vaccine expressing Zaire Ebola virus glycoprotein (ChAd3-EBO-Z). We aimed to investigate the safety, tolerability, and immunogenicity of ChAd3-EBO-Z in Malian and US adults, and assess the effect of boosting of Malians with modified vaccinia Ankara expressing Zaire Ebola virus glycoprotein and other filovirus antigens (MVA-BN-Filo).Methods: In the phase 1, single-blind, randomised trial of ChAd3-EBO-Z in the USA, we recruited adults aged 18-65 years from the University of Maryland medical community and the Baltimore community. In the phase 1b, open-label and double-blind, dose-escalation trial of ChAd3-EBO-Z in Mali, we recruited adults 18-50 years of age from six hospitals and health centres in Bamako (Mali), some of whom were also eligible for a nested, randomised, double-blind, placebo-controlled trial of MVA-BN-Filo. For randomised segments of the Malian trial and for the US trial, we randomly allocated participants (1:1; block size of six [Malian] or four [US]; ARB produced computer-generated randomisation lists; clinical staff did randomisation) to different single doses of intramuscular immunisation with ChAd3-EBO-Z: Malians received 1 × 10(10) viral particle units (pu), 2·5 × 10(10) pu, 5 × 10(10) pu, or 1 × 10(11) pu; US participants received 1 × 10(10) pu or 1 × 10(11) pu. We randomly allocated Malians in the nested trial (1:1) to receive a single dose of 2 × 10(8) plaque-forming units of MVA-BN-Filo or saline placebo. In the double-blind segments of the Malian trial, investigators, clinical staff, participants, and immunology laboratory staff were masked, but the study pharmacist (MK), vaccine administrator, and study statistician (ARB) were unmasked. In the US trial, investigators were not masked, but participants were. Analyses were per protocol. The primary outcome was safety, measured with occurrence of adverse events for 7 days after vaccination. Both trials are registered with ClinicalTrials.gov, numbers NCT02231866 (US) and NCT02267109 (Malian).Findings: Between Oct 8, 2014, and Feb 16, 2015, we randomly allocated 91 participants in Mali (ten [11%] to 1 × 10(10) pu, 35 [38%] to 2·5 × 10(10) pu, 35 [38%] to 5 × 10(10) pu, and 11 [12%] to 1 × 10(11) pu) and 20 in the USA (ten [50%] to 1 × 10(10) pu and ten [50%] to 1 × 10(11) pu), and boosted 52 Malians with MVA-BN-Filo (27 [52%]) or saline (25 [48%]). We identified no safety concerns with either vaccine: seven (8%) of 91 participants in Mali (five [5%] received 5 × 10(10) and two [2%] received 1 × 10(11) pu) and four (20%) of 20 in the USA (all received 1 × 10(11) pu) given ChAd3-EBO-Z had fever lasting for less than 24 h, and 15 (56%) of 27 Malians boosted with MVA-BN-Filo had injection-site pain or tenderness.Interpretation: 1 × 10(11) pu single-dose ChAd3-EBO-Z could suffice for phase 3 efficacy trials of ring-vaccination containment needing short-term, high-level protection to interrupt transmission. MVA-BN-Filo boosting, although a complex regimen, could confer long-lived protection if needed (eg, for health-care workers).Funding: Wellcome Trust, Medical Research Council UK, Department for International Development UK, National Cancer Institute, Frederick National Laboratory for Cancer Research, Federal Funds from National Institute of Allergy and Infectious Diseases. [ABSTRACT FROM AUTHOR]

Abstract: The oral, pentavalent rotavirus vaccine (PRV), RotaTeq was assessed for prevention of severe rotavirus gastroenteritis (RVGE) in young children in two multi-site, randomized, placebo-controlled field trials; one in Asia (Vietnam and Bangladesh) and the other in sub-Saharan Africa (Ghana, Kenya and Mali). The efficacy results for the Mali site of the multi-country trial are presented here. We randomly assigned infants in a 1:1 ratio to receive 3 doses of PRV/placebo at approximately 6, 10, and 14 weeks of age. Gastroenteritis episodes were captured passively at the local health centers and by home visits. The primary study outcome was severe RVGE, as defined by a score of ≥11 using the Vesikari Clinical Scoring System occurring ≥14 days after the third dose until the end of the study. Other efficacy analyses included efficacy against severe RVGE through the first year and during the second years of life, as well as efficacy after receiving at least one dose of vaccine. In total, 1960 infants were enrolled in the trial at the Mali site and sera were collected on a subset of infants (approximately 150) for immunogenicity testing. In the first year of follow-up, largely due to cultural practices to visit traditional healers as the first point of care, the point estimate of efficacy was unreliable: the per protocol vaccine efficacy against severe RVGE was 1% (95% confidence interval [CI]: −431.7, 81.6); the intention-to-treat vaccine efficacy was 42.9% (95% CI: −125.7, 87.7). During the second year of follow-up, after the surveillance system was modified to adapt to local customs and health care seeking practices, the point estimate of per-protocol vaccine efficacy was 19.2% (95% CI: −23.1,47.3%). 82.5% of Malian infants (95% CI: 70.1,91.3%) who received PRV mounted a seroresponse (≥3-fold rise from baseline (prevaccination) to post-dose 3 vaccination) of anti-rotavirus immunoglobulin A antibody, with a post third-dose geometric mean titer (GMT) of 31.3units/mL. By contrast, only 20.0% of placebo recipients (95% CI: 10.0, 33.7%) developed a seroresponse and the post-third dose GMT was 3.2units/mL. None of the serious clinical adverse events observed were considered to be vaccine-related. [Copyright &y& Elsevier]

Although seroprevalence studies have demonstrated the wide circulation of SARS-COV-2 in African countries, the impact on population health in these settings is still poorly understood. Using representative samples of the general population, we evaluated retrospective mortality and seroprevalence of anti-SARS-CoV-2 antibodies in Lubumbashi and Abidjan. The studies included retrospective mortality surveys and nested anti-SARS-CoV-2 antibody prevalence surveys. In Lubumbashi the study took place during April-May 2021 and in Abidjan the survey was implemented in two phases: July-August 2021 and October-November 2021. Crude mortality rates were stratified between pre-pandemic and pandemic periods and further investigated by age group and COVID waves. Anti-SARS-CoV-2 seroprevalence was quantified by rapid diagnostic testing (RDT) and laboratory-based testing (ELISA in Lubumbashi and ECLIA in Abidjan). In Lubumbashi, the crude mortality rate (CMR) increased from 0.08 deaths per 10 000 persons per day (pre-pandemic) to 0.20 deaths per 10 000 persons per day (pandemic period). Increases were particularly pronounced among <5 years old. In Abidjan, no overall increase was observed during the pandemic period (pre-pandemic: 0.05 deaths per 10 000 persons per day; pandemic: 0.07 deaths per 10 000 persons per day). However, an increase was observed during the third wave (0.11 deaths per 10 000 persons per day). The estimated seroprevalence in Lubumbashi was 15.7% (RDT) and 43.2% (laboratory-based). In Abidjan, the estimated seroprevalence was 17.4% (RDT) and 72.9% (laboratory-based) during the first phase of the survey and 38.8% (RDT) and 82.2% (laboratory-based) during the second phase of the survey. Although circulation of SARS-CoV-2 seems to have been extensive in both settings, the public health impact varied. The increases, particularly among the youngest age group, suggest indirect impacts of COVID and the pandemic on population health. The seroprevalence results confirmed substantial underdetection of cases through the national surveillance systems., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Simons et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: An effective, affordable, multivalent meningococcal conjugate vaccine is needed to prevent epidemic meningitis in the African meningitis belt. Data on the safety and immunogenicity of NmCV-5, a pentavalent vaccine targeting the A, C, W, Y, and X serogroups, have been limited., Methods: We conducted a phase 3, noninferiority trial involving healthy 2-to-29-year-olds in Mali and Gambia. Participants were randomly assigned in a 2:1 ratio to receive a single intramuscular dose of NmCV-5 or the quadrivalent vaccine MenACWY-D. Immunogenicity was assessed at day 28. The noninferiority of NmCV-5 to MenACWY-D was assessed on the basis of the difference in the percentage of participants with a seroresponse (defined as prespecified changes in titer; margin, lower limit of the 96% confidence interval [CI] above -10 percentage points) or geometric mean titer (GMT) ratios (margin, lower limit of the 98.98% CI >0.5). Serogroup X responses in the NmCV-5 group were compared with the lowest response among the MenACWY-D serogroups. Safety was also assessed., Results: A total of 1800 participants received NmCV-5 or MenACWY-D. In the NmCV-5 group, the percentage of participants with a seroresponse ranged from 70.5% (95% CI, 67.8 to 73.2) for serogroup A to 98.5% (95% CI, 97.6 to 99.2) for serogroup W; the percentage with a serogroup X response was 97.2% (95% CI, 96.0 to 98.1). The overall difference between the two vaccines in seroresponse for the four shared serogroups ranged from 1.2 percentage points (96% CI, -0.3 to 3.1) for serogroup W to 20.5 percentage points (96% CI, 15.4 to 25.6) for serogroup A. The overall GMT ratios for the four shared serogroups ranged from 1.7 (98.98% CI, 1.5 to 1.9) for serogroup A to 2.8 (98.98% CI, 2.3 to 3.5) for serogroup C. The serogroup X component of the NmCV-5 vaccine generated seroresponses and GMTs that met the prespecified noninferiority criteria. The incidence of systemic adverse events was similar in the two groups (11.1% in the NmCV-5 group and 9.2% in the MenACWY-D group)., Conclusions: For all four serotypes in common with the MenACWY-D vaccine, the NmCV-5 vaccine elicited immune responses that were noninferior to those elicited by the MenACWY-D vaccine. NmCV-5 also elicited immune responses to serogroup X. No safety concerns were evident. (Funded by the U.K. Foreign, Commonwealth, and Development Office and others; ClinicalTrials.gov number, NCT03964012.)., (Copyright © 2023 Massachusetts Medical Society.)

Respiratory syncytial virus (RSV) is the most common cause of early childhood lower respiratory tract infection (LRTI) in low- and middle-income countries (LMICs). Maternal vaccines, birth-dose extended half-life monoclonal antibodies (mAbs), and pediatric vaccines are under development for prevention of respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) in young children. We analyzed the health and economic impact of RSV interventions used alone or in combinations in Mali. We modeled age-specific and season-specific risks of RSV LRTI in children through three years, using WHO Preferred Product Characteristics and data generated in Mali. Health outcomes included RSV LRTI cases, hospitalizations, deaths, and disability-adjusted life-years (DALYs). We identified the optimal combination of products across a range of scenarios. We found that mAb delivered at birth could avert 878 DALYs per birth cohort at an incremental cost-effectiveness ratio (ICER) of $597 per DALY averted compared to no intervention if the product were available at $1 per dose. Combining mAb with pediatric vaccine administered at 10/14 weeks, 1947 DALYs would be prevented. The ICER of this combination strategy is $1514 per DALY averted compared to mAb alone. Incorporating parameter uncertainty, mAb alone is likely to be optimal from the societal perspective at efficacy against RSV LRTI above 66%. The optimal strategy was sensitive to economic considerations, including product prices and willingness-to-pay for DALYs. For example, the combination of mAb and pediatric vaccine would be optimal from the government perspective at a willingness-to-pay above $775 per DALY. Maternal vaccine alone or in combination with other interventions was never the optimal strategy, even for high vaccine efficacy. The same was true for pediatric vaccine administered at 6/7 months. At prices comparable to existing vaccine products, extended half-life RSV mAbs would be impactful and efficient components of prevention strategies in LMICs such as Mali., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: • Rachel S. Laufer reports no interests. • Ranju Baral reports that her institution has received research grants from the Bill and Melinda Gates Foundation. • Andrea G. Buchwald reports no interests. • James D. Campbell reports that his institution has received research grants from GlaxoSmithKline and Pfizer. • Flanon Coulibaly reports no interests. • Fatoumata Diallo reports no interests. • Moussa Doumbia reports no interests. • Amanda J. Driscoll reports no interests. • Alison P. Galvani reports no interests. • Adama M. Keita reports no interests. • Kathleen M. Neuzil reports that her institution has received research grants from GlaxoSmithKline, Pfizer, PATH, and National Institutes of Health for vaccine research. She is a member of SAGE. • Clint Pecenka reports that his institution has received research grants from the Bill and Melinda Gates Foundation. • Samba Sow reports no interests. • Justin R. Ortiz reports grants to his institution from National Science Foundation, Bill & Melinda Gates Foundation, Pfizer, National Institutes of Health, and World Health Organization outside the submitted work. • Meagan C. Fitzpatrick reports personal fees from Sanofi Pasteur, outside the submitted work., (Copyright: © 2023 Laufer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) in young children and is associated with subsequent recurrent wheezing illness and asthma (wheeze/asthma). RSV prevention may therefore reduce wheeze/asthma prevalence., Objectives: We estimated the contribution of RSV LRTI and the impact of RSV prevention on recurrent wheeze/asthma in Mali., Methods: We simulated 12 consecutive monthly birth cohorts in Mali and estimated RSV LRTI cases through 2 years and recurrent wheeze/asthma prevalence at 6 years under different RSV prevention scenarios: status quo, seasonal birth-dose extended half-life mAb, and seasonal birth-dose extended half-life mAb followed by 2 doses of pediatric vaccine (mAb + vaccine). We used World Health Organization (WHO) Preferred Product Characteristics for RSV prevention, demographic and RSV epidemiologic data from Mali, regional recurrent wheeze/asthma prevalence, and relative risk of recurrent wheeze/asthma given early childhood RSV LRTI., Results: Among the simulated cohort of 778,680 live births, 10.0% had RSV LRTI by 2 years and 89.6% survived to 6 years. We estimated that 13.4% of all recurrent wheeze/asthma at 6 years was attributable to RSV LRTI. Recurrent wheeze/asthma prevalence at 6 years was 145.0 per 10,000 persons (RSV LRTI attributable) and 1084.2 per 10,000 persons (total). In mAb and mAb + vaccine scenarios, RSV LRTI cases decreased by 11.8% and 44.4%, respectively, and recurrent wheeze/asthma prevalence decreased by 11.8% and 44.4% (RSV LRTI attributable) and 1.6% and 5.9% (total)., Conclusion: In Mali, RSV prevention programs may have a meaningful impact on chronic respiratory disease, strengthening the case for investment in RSV prevention., (© 2023 The Authors.)

Background: Questions remain concerning the rapidity of immune responses and the durability and safety of vaccines used to prevent Zaire Ebola virus disease., Methods: We conducted two randomized, placebo-controlled trials - one involving adults and one involving children - to evaluate the safety and immune responses of three vaccine regimens against Zaire Ebola virus disease: Ad26.ZEBOV followed by MVA-BN-Filo 56 days later (the Ad26-MVA group), rVSVΔG-ZEBOV-GP followed by placebo 56 days later (the rVSV group), and rVSVΔG-ZEBOV-GP followed by rVSVΔG-ZEBOV-GP 56 days later (the rVSV-booster group). The primary end point was antibody response at 12 months, defined as having both a 12-month antibody concentration of at least 200 enzyme-linked immunosorbent assay units (EU) per milliliter and an increase from baseline in the antibody concentration by at least a factor of 4., Results: A total of 1400 adults and 1401 children underwent randomization. Among both adults and children, the incidence of injection-site reactions and symptoms (e.g., feverishness and headache) was higher in the week after receipt of the primary and second or booster vaccinations than after receipt of placebo but not at later time points. These events were largely low-grade. At month 12, a total of 41% of adults (titer, 401 EU per milliliter) and 78% of children (titer, 828 EU per milliliter) had a response in the Ad26-MVA group; 76% (titer, 992 EU per milliliter) and 87% (titer, 1415 EU per milliliter), respectively, had a response in the rVSV group; 81% (titer, 1037 EU per milliliter) and 93% (titer, 1745 EU per milliliter), respectively, had a response in the rVSV-booster group; and 3% (titer, 93 EU per milliliter) and 4% (titer, 67 EU per milliliter), respectively, had a response in the placebo group (P<0.001 for all comparisons of vaccine with placebo). In both adults and children, antibody responses with vaccine differed from those with placebo beginning on day 14., Conclusions: No safety concerns were identified in this trial. With all three vaccine regimens, immune responses were seen from day 14 through month 12. (Funded by the National Institutes of Health and others; PREVAC ClinicalTrials.gov number, NCT02876328; EudraCT numbers, 2017-001798-18 and 2017-001798-18/3rd; and Pan African Clinical Trials Registry number, PACTR201712002760250.)., (Copyright © 2022 Massachusetts Medical Society.)

Reactive immunization with a single-dose cholera vaccine that could rapidly (within days) protect immunologically naive individuals during virgin soil epidemics, when cholera reaches immunologically naive populations that have not experienced cholera for decades, would facilitate cholera control. One dose of attenuated Vibrio cholerae O1 classical Inaba vaccine CVD 103-HgR (Vaxchora) containing ≥2 × 10 8 CFU induces vibriocidal antibody seroconversion (a correlate of protection) in >90% of U.S. adults. A previous CVD 103-HgR commercial formulation required ≥2 × 10 9 CFU to elicit high levels of seroconversion in populations in developing countries. We compared the vibriocidal responses of Malians (individuals 18 to 45 years old) randomized to ingest a single ≥2 × 10 8 -CFU standard dose ( n = 50) or a ≥2 × 10 9 -CFU high dose ( n = 50) of PaxVax CVD 103-HgR with buffer or two doses ( n = 50) of Shanchol inactivated cholera vaccine (the immunologic comparator). To maintain blinding, participants were dosed twice 2 weeks apart; CVD 103-HgR recipients ingested placebo 2 weeks before or after ingesting vaccine. Seroconversion (a ≥4-fold vibriocidal titer rise) between the baseline and 14 days after CVD 103-HgR ingestion and following the first and second doses of Shanchol were the main outcomes measured. By day 14 postvaccination, the rates of seroconversion after ingestion of a single standard dose and a high dose of CVD 103-HgR were 71.7% (33/46 participants) and 83.3% (40/48 participants), respectively. The rate of seroconversion following the first dose of Shanchol, 56.0% (28/50 participants), was significantly lower than that following the high dose of CVD 103-HgR ( P = 0.003). The vibriocidal geometric mean titer (GMT) of the high dose of CVD 103-HgR exceeded the GMT of the standard dose at day 14 (214 versus 95, P = 0.045) and was ∼2-fold higher than the GMT on day 7 and day 14 following the first Shanchol dose ( P > 0.05). High-dose CVD 103-HgR is recommended for accelerated evaluation in developing countries to assess its efficacy and practicality in field situations. (This study has been registered at ClinicalTrials.gov under registration no. NCT02145377.)., (Copyright © 2017 Sow et al.)