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75 result(s)
Journal Article > ResearchFull Text

Body mass index trajectories and association with tuberculosis risk in a cohort of household contacts in Southern Africa

Clin Infect Dis. 28 April 2025; DOI:doi: 10.1093/cid/ciaf222
Larsson L, Calderwood CJ, Marambire ET, Held K, Banze D,  et al.
Clin Infect Dis. 28 April 2025; DOI:doi: 10.1093/cid/ciaf222

BACKGROUND

Studies have demonstrated an inverse log-linear relationship between body mass index (BMI) and tuberculosis incidence. However, a person’s BMI is dynamic and longitudinal changes may be more informative than cross-sectional assessments. We evaluate the association between cross-sectional and changing BMI and risk of tuberculosis and describe longitudinal trajectories in a high-risk cohort.


METHODS

ERASE-TB was a prospective longitudinal cohort study of household contacts ≥10 years in Southern Africa (Zimbabwe, Tanzania, and Mozambique), with 6-monthly follow-up up to 24 months. Associations between BMI and tuberculosis were investigated based on baseline (including haemoglobin) and changing BMI, using logistic, Poisson, and Cox models. Prevalent tuberculosis was defined as diagnosis during <30 days after recruitment. Growth mixture modelling (GMM) was used to model longitudinal latent trajectories.


RESULTS

Of 2,107 recruited household contacts (621 [29.5%] adolescents and 1,310 [62.2%] female), 520 (24.7%) were underweight. There were 21 and 41 people diagnosed with prevalent and incident tuberculosis, of whom 5/21 (23.8%) and 12/41 (29.3%) were underweight. Being underweight and anaemic (aHR: 3.77, 95% CI: 1.50-9.51) and >10% negative change in BMI during follow-up (aIRR: 2.27 (95% CI: 0.22-22.9) were associated with increased risk of incident tuberculosis. The association between continuous BMI-for-age Z-scores were non-linear, with increased risk of tuberculosis with lower BMI. Four latent groups were defined in the GMM: increasing, decreasing, and low/high stable BMI.


CONCLUSIONS

Declining BMI, regardless of absolute value, is a strong predictor of tuberculosis among household contacts. Longitudinal measurements should be considered in active case finding among tuberculosis-affected households.

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Journal Article > Pre-PrintFull Text

A comparison of acceptability of contraceptive vaginal rings, pills, and injectables among cisgender women in Kenya and Zimbabwe: protocol for a mixed-methods study

VeriXiv. 20 December 2024; DOI:10.12688/verixiv.471.1
Polis CB, Obare FO, Bruce IV, Banda C, Haddad LB,  et al.
VeriXiv. 20 December 2024; DOI:10.12688/verixiv.471.1

BACKGROUND

Expanding contraceptive options could better meet users’ diverse needs and preferences. Annovera® is a contraceptive vaginal ring that provides a year of pregnancy prevention while remaining under user control and allowing for regular menstrual cycles. This method may also help to reduce burdens on some health care and supply chain systems. However, knowledge gaps exist regarding initial and ongoing acceptability of contraceptive vaginal rings in African settings.

METHODS

We will undertake an open-label, non-randomized, two-arm, parallel clinical acceptability study with an embedded qualitative component, based in clinics providing contraceptive services in Kenya and Zimbabwe. Women aged 18-45 interested in newly initiating or switching contraception will choose from among all available contraceptive options, including Annovera. We aim to enroll 200 participants selecting Annovera and 200 participants selecting either contraceptive injectables or pills. We will compare method uptake, continuation, and satisfaction over one year. Participants will complete questionnaires administered by study staff during two in-person visits (a screening/enrollment visit, and an end of study visit after 52 weeks of method use or at discontinuation) and four phone appointments (at 4, 12, 24, and 36 weeks of use). We will evaluate used rings for discoloration and residual drug levels. The qualitative component involve in-depth interviews with women in the clinical study, their sexual partners, and their service providers, to further examine drivers of and barriers to interest in and use of contraceptive vaginal rings.


DISCUSSION

This study will explore acceptability of contraceptive vaginal rings in ‘real-world’ contraceptive service settings in two African countries. Findings will be based on actual ring use and contextualized via comparison to two other commonly available methods. As vaginal rings are being considered for multiple reproductive health indications, this work can fill key knowledge gaps and empower decision-makers with information needed to inform future investments in reproductive health.

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Journal Article > ReviewFull Text

Carriage of third-generation cephalosporin-resistant and carbapenem-resistant Enterobacterales among children in sub-Saharan Africa: a systematic review and meta-analysis

E Clinical Medicine. 11 March 2024; Volume 70; 102508.; DOI:10.1016/j.eclinm.2024.102508
Ruef M, Emonet S, Merglen A, Dewez JE, Obama BM,  et al.
E Clinical Medicine. 11 March 2024; Volume 70; 102508.; DOI:10.1016/j.eclinm.2024.102508
BACKGROUND
The increasing resistance of Enterobacterales to third-generation cephalosporins and carbapenems in sub-Saharan Africa (SSA) is a major public health concern. We did a systematic review and meta-analysis of studies to estimate the carriage prevalence of Enterobacterales not susceptible to third-generation cephalosporins or carbapenems among paediatric populations in SSA.

METHODS
We performed a systematic literature review and meta-analysis of cross-sectional and cohort studies to estimate the prevalence of childhood (0-18 years old) carriage of extended-spectrum cephalosporin-resistant Enterobacterales (ESCR-E) or carbapenem-resistant Enterobacterales (CRE) in SSA. Medline, EMBASE and the Cochrane Library were searched for studies published from 1 January 2005 to 1 June 2022. Studies with <10 occurrences per bacteria, case reports, and meta-analyses were excluded. Quality and risk of bias were assessed using the Newcastle-Ottawa scale. Meta-analyses of prevalences and odds ratios were calculated using generalised linear mixed-effects models. Heterogeneity was assessed using I2 statistics. The protocol is available on PROSPERO (CRD42021260157).

FINDINGS
Of 1111 studies examined, 40 met our inclusion criteria, reporting on the carriage prevalence of Enterobacterales in 9408 children. The pooled carriage prevalence of ESCR-E was 32.2% (95% CI: 25.2%-40.2%). Between-study heterogeneity was high (I2 = 96%). The main sources of bias pertained to participant selection and the heterogeneity of the microbiological specimens. Carriage proportions were higher among sick children than healthy ones (35.7% vs 16.9%). The pooled proportion of nosocomial acquisition was 53.8% (95% CI: 32.1%-74.1%) among the 922 children without ESCR-E carriage at hospital admission. The pooled odds ratio of ESCR-E carriage after antibiotic treatment within the previous 3 months was 3.20 (95% CI: 2.10-4.88). The proportion of pooled carbapenem-resistant for Enterobacterales was 3.6% (95% CI: 0.7%-16.4%).

INTERPRETATION
This study suggests that ESCR-E carriage among children in SSA is frequent. Microbiology capacity and infection control must be scaled-up to reduce the spread of those multidrug-resistant microorganisms.
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Journal Article > ReviewFull Text

Antimicrobial resistance in Enterobacterales infections among children in sub-Saharan Africa: a systematic review and meta-analysis

E Clinical Medicine. 8 March 2024; Volume 70; 102512.; DOI:10.1016/j.eclinm.2024.102512
Kowalski M, Minka Obama B, Catho G, Dewez JE, Merglen A,  et al.
E Clinical Medicine. 8 March 2024; Volume 70; 102512.; DOI:10.1016/j.eclinm.2024.102512
BACKGROUND
The burden of antimicrobial resistance (AMR) has been estimated to be the highest in sub-Saharan Africa (SSA). The current study estimated the proportion of drug-resistant Enterobacterales causing infections in SSA children.

METHODS
We searched MEDLINE/PubMed, Embase and the Cochrane Library to identify retrospective and prospective studies published from 01/01/2005 to 01/06/2022 reporting AMR of Enterobacterales causing infections in sub-Saharan children (0-18 years old). Studies were excluded if they had unclear documentation of antimicrobial susceptibility testing methods or fewer than ten observations per bacteria. Data extraction and quality appraisal were conducted by two authors independently. The primary outcome was the proportion of Enterobacterales resistant to antibiotics commonly used in paediatrics. Proportions were combined across studies using mixed-effects logistic regression models per bacteria and per antibiotic. Between-study heterogeneity was assessed using the I2 statistic. The protocol was registered with PROSPERO (CRD42021260157).

FINDINGS
After screening 1111 records, 122 relevant studies were included, providing data on more than 30,000 blood, urine and stool isolates. Escherichia coli and Klebsiella spp. were the predominant species, both presenting high proportions of resistance to third-generation cephalosporins, especially in blood cultures: 40.6% (95% CI: 27.7%-55%; I2: 85.7%, number of isolates (n): 1032) and 84.9% (72.8%-92.2%; I2: 94.1%, n: 2067), respectively. High proportions of resistance to other commonly used antibiotics were also observed. E. coli had high proportions of resistance, especially for ampicillin (92.5%; 95% CI: 76.4%-97.9%; I2: 89.8%, n: 888) and gentamicin (42.7%; 95% CI: 30%-56.5%; I2: 71.9%, n: 968). Gentamicin-resistant Klebsiella spp. were also frequently reported (77.6%; 95% CI: 65.5%-86.3%; I2: 91.6%, n: 1886).

INTERPRETATION
High proportions of resistance to antibiotics commonly used for empirical treatment of infectious syndromes were found for Enterobacterales in sub-Saharan children. There is a critical need to better identify local patterns of AMR to inform and update clinical guidelines for better treatment outcomes.
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Journal Article > ResearchFull Text

Adolescents and young adults are the most undiagnosed of HIV and virally unsuppressed in Eastern and Southern Africa: Pooled analyses from five population-based surveys

PLOS Glob Public Health. 22 December 2023; Volume 3 (Issue 12); e0002398.; DOI:10.1371/journal.pgph.0002398
Huerga H, Farhat JB, Maman D, Conan N, Van Cutsem G,  et al.
PLOS Glob Public Health. 22 December 2023; Volume 3 (Issue 12); e0002398.; DOI:10.1371/journal.pgph.0002398
Age and gender disparities within the HIV cascade of care are critical to focus interventions efficiently. We assessed gender-age groups at the highest probability of unfavorable outcomes in the HIV cascade in five HIV prevalent settings. We performed pooled data analyses from population-based surveys conducted in Kenya, South Africa, Malawi and Zimbabwe between 2012 and 2016. Individuals aged 15–59 years were eligible. Participants were tested for HIV and viral load was measured. The HIV cascade outcomes and the probability of being undiagnosed, untreated among those diagnosed, and virally unsuppressed (≥1,000 copies/mL) among those treated were assessed for several age-gender groups. Among 26,743 participants, 5,221 (19.5%) were HIV-positive (69.9% women, median age 36 years). Of them, 72.8% were previously diagnosed and 56.7% virally suppressed (88.5% among those treated). Among individuals 15–24 years, 51.5% were diagnosed vs 83.0% among 45–59 years, p<0.001. Among 15–24 years diagnosed, 60.6% were treated vs 86.5% among 45–59 years, p<0.001. Among 15–24 years treated, 77.9% were virally suppressed vs 92.0% among 45–59 years, p<0.001. Among all HIV-positive, viral suppression was 32.9% in 15–24 years, 47.9% in 25–34 years, 64.9% in 35–44 years, 70.6% in 45–59 years. Men were less diagnosed than women (65.2% vs 76.0%, p<0.001). Treatment among diagnosed and viral suppression among treated was not different by gender. Compared to women 45–59 years, young people had a higher probability of being undiagnosed (men 15–24 years OR: 37.9, women 15–24 years OR: 12.2), untreated (men 15–24 years OR:2.2, women 15–24 years OR: 5.7) and virally unsuppressed (men 15–24 years OR: 1.6, women 15–24 years OR: 6.6). In these five Eastern and Southern Africa settings, adolescents and young adults had the largest gaps in the HIV cascade. They were less diagnosed, treated, and virally suppressed, than older counterparts. Targeted preventive, testing and treating interventions should be scaled-up.More
Journal Article > ResearchFull Text

Descriptive epidemiology of the cholera outbreak in Zimbabwe 2018–2019: role of multi-sectorial approach in cholera epidemic control

BMJ Open. 30 January 2023; Volume 13 (Issue 1); e059134.; DOI:10.1136/bmjopen-2021-059134
Mashe T, Chaibva BV, Nair P, Sani KA, Jallow M,  et al.
BMJ Open. 30 January 2023; Volume 13 (Issue 1); e059134.; DOI:10.1136/bmjopen-2021-059134
OBJECTIVES
This study was conducted to explore the epidemiology and microbiological pattern of the cholera outbreaks that occurred in Zimbabwe from 2018 to 2019.

STUDY SETTING AND DESIGN
This descriptive study used secondary data of 9971 out of 10 730 suspected cases from the Zimbabwean National Diseases Surveillance system and microbiology data of 241 out of 371 patients from the National Microbiology Reference Laboratory in Harare, for the period 5 September 2018 and 3 January 2019. Descriptive analysis was performed to describe the characteristics of the outbreak in terms of person, place and time.

RESULTS
A cumulative total of 10 730 suspected, 371 laboratory-confirmed cholera cases and 68 deaths were reported in Zimbabwe through the situation analysis report (sitrep). The attack rate during the outbreak was 174.6 per 100 000 with a case fatality rate of 0.63%. Most cases seen were among adults from Harare province. Antimicrobial sensitivity testing results showed that a multidrug resistant strain of Vibrio cholerae O1, Ogawa serotype was responsible for the outbreak. The treatment of cases was changed from the standard recommended medicine ciprofloxacin to azithromycin as confirmed by the antimicrobial sensitivity test results. Strategies employed to contain the outbreak included mass oral cholera vaccination in the hotspot areas of Harare, provision of improved and appropriate sanitation measures, provision of safe and adequate water, chlorination of water and improved waste management practice.

CONCLUSIONS
The recurrence of a cholera outbreak is a global concern, especially with the emergence of multi-drug resistant strains of the causal organism. Improving water, sanitation, hygiene infrastructure, health system strengthening measures and inter-sectoral collaboration in responding to the cholera outbreak was key to controlling the outbreak.
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Journal Article > ResearchFull Text

Time, space and health: using the life history calendar methodology applied to mobility in a medical-humanitarian organisation

Glob Health Action. 6 October 2022; Volume 15 (Issue 1); DOI:10.1080/16549716.2022.2128281
Cubides JC, Jorgensen N, Peiter PC
Glob Health Action. 6 October 2022; Volume 15 (Issue 1); DOI:10.1080/16549716.2022.2128281
In the medical humanitarian context, the challenging task of collecting health information from people on the move constitutes a key element to identifying critical health care needs and gaps. Médecins Sans Frontières (MSF), during its long history of working with migrants, refugees and mobile populations in different contexts, has acknowledged how crucial it is to generate detailed context-related data on migrant and refugee populations in order to adapt the response interventions to their needs and circumstances. In 2019, the Brazilian Medical Unit/MSF developed the Migration History Tool (MHT), an application based on the life history method which was created in close dialogue with field teams in order to respond to information needs emerging from medical operations in mobile populations. The tool was piloted in two different contexts: firstly, among mobile populations transiting and living in Beitbridge and Musina, at the Zimbabwe-South Africa border; and, secondly, among Venezuelan migrants and refugees in Colombia. This article describes the implementation of this innovative method for collecting quantitative retrospective data on mobility and health in the context of two humanitarian interventions. The results have proven the flexibility of the methodology, which generated detailed information on mobility trajectories and on the temporalities of migration in two different contexts. It also revealed how health outcomes are not only associated with the spatial dimensions of movement, but also with the temporalities of mobility trajectories.More
Journal Article > ResearchFull Text

Cholera outbreaks in sub-Saharan Africa during 2010-2019: a descriptive analysis

Int J Infect Dis. 1 September 2022; Volume 122; 215-221.; DOI:10.1016/j.ijid.2022.05.039
Zheng Q, Luquero FJ, Ciglenecki I, Wamala JF, Abubakar A,  et al.
Int J Infect Dis. 1 September 2022; Volume 122; 215-221.; DOI:10.1016/j.ijid.2022.05.039
BACKGROUND
Cholera remains a public health threat but is inequitably distributed across sub-Saharan Africa. Lack of standardized reporting and inconsistent outbreak definitions limit our understanding of cholera outbreak epidemiology.

METHODS
From a database of cholera incidence and mortality, we extracted data from sub-Saharan Africa and reconstructed outbreaks of suspected cholera starting in January 2010 to December 2019 based on location-specific average weekly incidence rate thresholds. We then described the distribution of key outbreak metrics.

RESULTS
We identified 999 suspected cholera outbreaks in 744 regions across 25 sub-Saharan African countries. The outbreak periods accounted for 1.8 billion person-months (2% of the total during this period) from January 2010 to January 2020. Among 692 outbreaks reported from second-level administrative units (e.g., districts), the median attack rate was 0.8 per 1000 people (interquartile range (IQR), 0.3-2.4 per 1000), the median epidemic duration was 13 weeks (IQR, 8-19), and the median early outbreak reproductive number was 1.8 (range, 1.1-3.5). Larger attack rates were associated with longer times to outbreak peak, longer epidemic durations, and lower case fatality risks.

CONCLUSIONS
This study provides a baseline from which the progress toward cholera control and essential statistics to inform outbreak management in sub-Saharan Africa can be monitored.
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Journal Article > ResearchFull Text

Implementation of an outbreak response vaccination campaign with typhoid conjugate vaccine – Harare, Zimbabwe, 2019

Vaccine. 2 August 2022; Volume 12; 100201.; DOI:10.1016/j.jvacx.2022.100201
Poncin M, Marembo J, Chitando P, Sreenivasan N, Makwara I,  et al.
Vaccine. 2 August 2022; Volume 12; 100201.; DOI:10.1016/j.jvacx.2022.100201
INTRODUCTION
Typhoid fever is a public-health problem in Harare, the capital city of Zimbabwe, with seasonal outbreaks occurring annually since 2010. In 2019, the Ministry of Health and Child Care (MOHCC) organized the first typhoid conjugate vaccination campaign in Africa in response to a recurring typhoid outbreak in a large urban setting.

METHODS
As part of a larger public health response to a typhoid fever outbreak in Harare, Gavi approved in September 2018 a MOHCC request for 340,000 doses of recently prequalified Typbar-TCV to implement a mass vaccination campaign. To select areas for the campaign, typhoid fever surveillance data from January 2016 until June 2018 was reviewed. We collected and analyzed information from the MOHCC and its partners to describe the vaccination campaign planning, implementation, feasibility, administrative coverage and financial costs.

RESULTS
The campaign was conducted in nine high-density suburbs of Harare over eight days in February-March 2019 and targeted all children aged 6 months-15 years; however, the target age range was extended up to 45 years in one suburb due to the past high attack rate among adults. A total of 318,698 people were vaccinated, resulting in overall administrative coverage of 85.4 percent. More than 750 community volunteers and personnel from the MOHCC and the Ministry of Education were trained and involved in social mobilization and vaccination activities. The MOHCC used a combination of vaccination strategies (i.e., fixed and mobile immunization sites, a creche and school-based strategy, and door-to-door activities). Financial costs were estimated at US$ 2.39 per dose, including the vaccine and vaccination supplies (US$ 0.79 operational costs per dose excluding vaccine and vaccination supplies).

CONCLUSIONS
A mass targeted campaign in densely populated urban areas in Harare, using the recently prequalified typhoid conjugate vaccine, was feasible and achieved a high overall coverage in a short period of time.
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Protocol > Research Protocol

Effectiveness of case-area targeted interventions including vaccination on the control of epidemic cholera: protocol for a prospective observational study

BMJ Open. 6 July 2022; Volume 12 (Issue 7); e061206.; DOI:10.1136/bmjopen-2022-061206
Ratnayake R, Peyraud N, Ciglenecki I, Gignoux EM, Lightowler M,  et al.
BMJ Open. 6 July 2022; Volume 12 (Issue 7); e061206.; DOI:10.1136/bmjopen-2022-061206
INTRODUCTION
Cholera outbreaks in fragile settings are prone to rapid expansion. Case-area targeted interventions (CATIs) have been proposed as a rapid and efficient response strategy to halt or substantially reduce the size of small outbreaks. CATI aims to deliver synergistic interventions (eg, water, sanitation, and hygiene interventions, vaccination, and antibiotic chemoprophylaxis) to households in a 100-250 m 'ring' around primary outbreak cases.

METHODS AND ANALYSIS
We report on a protocol for a prospective observational study of the effectiveness of CATI. Médecins Sans Frontières (MSF) plans to implement CATI in the Democratic Republic of the Congo (DRC), Cameroon, Niger and Zimbabwe. This study will run in parallel to each implementation. The primary outcome is the cumulative incidence of cholera in each CATI ring. CATI will be triggered immediately on notification of a case in a new area. As with most real-world interventions, there will be delays to response as the strategy is rolled out. We will compare the cumulative incidence among rings as a function of response delay, as a proxy for performance. Cross-sectional household surveys will measure population-based coverage. Cohort studies will measure effects on reducing incidence among household contacts and changes in antimicrobial resistance.

ETHICS AND DISSEMINATION
The ethics review boards of MSF and the London School of Hygiene and Tropical Medicine have approved a generic protocol. The DRC and Niger-specific versions have been approved by the respective national ethics review boards. Approvals are in process for Cameroon and Zimbabwe. The study findings will be disseminated to the networks of national cholera control actors and the Global Task Force for Cholera Control using meetings and policy briefs, to the scientific community using journal articles, and to communities via community meetings.
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