Journal Article > ReviewFull Text
PLOS Glob Public Health. 2024 April 16; Volume 4 (Issue 4); e0003077.; DOI:10.1371/journal.pgph.0003077
Monk EJM, Jones TPW, Bongomin F, Kibone W, Nsubuga Y, et al.
PLOS Glob Public Health. 2024 April 16; Volume 4 (Issue 4); e0003077.; DOI:10.1371/journal.pgph.0003077
Antimicrobial resistance (AMR) is a major global threat and AMR-attributable mortality is particularly high in Central, Eastern, Southern and Western Africa. The burden of clinically infected wounds, skin and soft tissue infections (SSTI) and surgical site infections (SSI) in these regions is substantial. This systematic review reports the extent of AMR from sampling of these infections in Africa, to guide treatment. It also highlights gaps in microbiological diagnostic capacity. PubMed, MEDLINE and Embase were searched for studies reporting the prevalence of Staphylococcus aureus, Eschericheria coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii in clinically infected wounds, SSTI and SSI in Central, Eastern, Southern or Western Africa, and studies reporting AMR from such clinical isolates. Estimates for proportions were pooled in meta-analyses, to estimate the isolation prevalence of each bacterial species and the proportion of resistance observed to each antibiotic class. The search (15th August 2022) identified 601 articles: 59 studies met our inclusion criteria. S. aureus was isolated in 29% (95% confidence interval [CI] 25% to 34%) of samples, E. coli in 14% (CI 11% to 18%), K. pneumoniae in 11% (CI 8% to 13%), P. aeruginosa in 14% (CI 11% to 18%) and A. baumannii in 8% (CI 5% to 12%). AMR was high across all five species. S. aureus was resistant to methicillin (MRSA) in >40% of isolates. E. coli and K. pneumoniae were both resistant to amoxicillin-clavulanic acid in ≥80% of isolates and resistant to aminoglycosides in 51% and 38% of isolates respectively. P. aeruginosa and A. baumannii were both resistant to anti-pseudomonal carbapenems (imipenem or meropenem) in ≥20% of isolates. This systematic review found that a large proportion of the organisms isolated from infected wounds, SSTI and SSI in Africa displayed resistance patterns of World Health Organisation (WHO) priority pathogens for critical or urgent antimicrobial development.
Journal Article > CommentaryFull Text
Vaccine. 2019 October 23; Volume 37; DOI:10.1016/j.vaccine.2019.09.038
van Zandvoort K, Checchi F, Diggle E, Eggo RM, Gadroen K, et al.
Vaccine. 2019 October 23; Volume 37; DOI:10.1016/j.vaccine.2019.09.038
Streptococcus pneumoniae is a common human commensal that causes a sizeable part of the overall childhood mortality in low income settings. Populations affected by humanitarian crises are at especially high risk, because a multitude of risk factors that are enhanced during crises increase pneumococcal transmission and disease severity. Pneumococcal conjugate vaccines (PCVs) provide effective protection and have been introduced into the majority of routine childhood immunisation programmes globally, though several barriers have hitherto limited their uptake during humanitarian crises. When PCV coverage cannot be sustained during crises or when PCV has not been part of routine programmes, mass vaccination campaigns offer a quick acting and programmatically feasible bridging solution until services can be restored. However, we currently face a paucity of evidence on which to base the structure of such campaigns. We believe that, now that PCV can be procured at a substantially reduced price through the Humanitarian Mechanism, this lack of information is a remaining hurdle to PCV use in humanitarian crises. Considering the difficulties in conducting research in crises, we propose an evidence generation pathway consisting of primary data collection in combination with mathematical modelling followed by quasi-experimental evaluation of a PCV intervention, which can inform on optimal vaccination strategies that consider age targeting, dosing regimens and impact duration.
Conference Material > Slide Presentation
van Zandvoort K, Bobe M, Hassan AM, Ismail M, Saed M, et al.
MSF Scientific Days International 2023. 2023 June 7; DOI:10.57740/t9ve-m563
Conference Material > Abstract
van Zandvoort K, Bobe M, Buqul A, Ismail M, Saed M, et al.
MSF Scientific Days International 2023. 2023 June 7; DOI:10.57740/cxek-yg24
INTRODUCTION
Despite a likely high burden of disease caused by Streptococcus pneumoniae in humanitarian crises, pneumococcal conjugate vaccines (PCV’s) are rarely used in such settings. Routine immunisation is rarely feasible in crises, and there is little evidence on alternative delivery strategies for PCV. We used modelling to evaluate the effects of different vaccination strategies within humanitarian crisis settings, aiming to identify those which could quickly reduce and sustain low transmission of vaccine serotypes.
METHODS
We conducted a nested carriage and contact survey in a camp for internally displaced people (IDP) in Somaliland to parameterise a transmission model and used it to assess the potential impact and optimal age targeting of PCV campaigns. We extrapolated this model to other representative humanitarian crisis settings: an acute-phase IDP camp, a protracted crisis in a rural setting, and an urban setting with mixed IDP and host communities. For each we explored the impact and efficiency of campaigns with different target age groups and dosing strategies.
ETHICS
This study was approved by the Ethics Review Boards of the London School of Hygiene and Tropical Medicine and the Republic of Somaliland Ministry of Health Development.
RESULTS
We found high prevalence of nasopharyngeal carriage of Streptococcus pneumoniae; 37% (95% confidence interval (CI), 32-42) in all ages, and 76% (95% CI, 70-82) in children <5 years in the Somaliland IDP camp. 53% (95% CI, 45-61) of serotypes are included in the PCV13 vaccine. People had, on average, 9 (9-10) contacts per day, with high mixing rates between children and intergenerational contacts in older age groups. Our model projects that, for the Somaliland IDP camp, a single PCV campaign including children <5 years can temporarily establish substantial herd protection, averting 37% (95% credible interval (CrI) 24-48) of invasive pneumococcal disease cases in the 2 years following the campaign. Extending age eligibility to children up to 10 or 15 years old could further increase this impact by 49% (95% CrI, 39-50) and 53% (95% CrI, 40-64) respectively. Increased migration rates and close contact with unvaccinated host populations reduces the impact. These factors might require wider age targeting and more frequent repeat campaigns until routine services could be re-established.
CONCLUSION
We show that PCV campaigns could be an effective option to reduce the burden of pneumococcal disease in humanitarian crises until routine immunisation can be implemented. Our results are based on modelled estimates, intervention studies are needed to evaluate their feasibility and effectiveness in real settings.
CONFLICTS OF INTEREST
None declared
Despite a likely high burden of disease caused by Streptococcus pneumoniae in humanitarian crises, pneumococcal conjugate vaccines (PCV’s) are rarely used in such settings. Routine immunisation is rarely feasible in crises, and there is little evidence on alternative delivery strategies for PCV. We used modelling to evaluate the effects of different vaccination strategies within humanitarian crisis settings, aiming to identify those which could quickly reduce and sustain low transmission of vaccine serotypes.
METHODS
We conducted a nested carriage and contact survey in a camp for internally displaced people (IDP) in Somaliland to parameterise a transmission model and used it to assess the potential impact and optimal age targeting of PCV campaigns. We extrapolated this model to other representative humanitarian crisis settings: an acute-phase IDP camp, a protracted crisis in a rural setting, and an urban setting with mixed IDP and host communities. For each we explored the impact and efficiency of campaigns with different target age groups and dosing strategies.
ETHICS
This study was approved by the Ethics Review Boards of the London School of Hygiene and Tropical Medicine and the Republic of Somaliland Ministry of Health Development.
RESULTS
We found high prevalence of nasopharyngeal carriage of Streptococcus pneumoniae; 37% (95% confidence interval (CI), 32-42) in all ages, and 76% (95% CI, 70-82) in children <5 years in the Somaliland IDP camp. 53% (95% CI, 45-61) of serotypes are included in the PCV13 vaccine. People had, on average, 9 (9-10) contacts per day, with high mixing rates between children and intergenerational contacts in older age groups. Our model projects that, for the Somaliland IDP camp, a single PCV campaign including children <5 years can temporarily establish substantial herd protection, averting 37% (95% credible interval (CrI) 24-48) of invasive pneumococcal disease cases in the 2 years following the campaign. Extending age eligibility to children up to 10 or 15 years old could further increase this impact by 49% (95% CrI, 39-50) and 53% (95% CrI, 40-64) respectively. Increased migration rates and close contact with unvaccinated host populations reduces the impact. These factors might require wider age targeting and more frequent repeat campaigns until routine services could be re-established.
CONCLUSION
We show that PCV campaigns could be an effective option to reduce the burden of pneumococcal disease in humanitarian crises until routine immunisation can be implemented. Our results are based on modelled estimates, intervention studies are needed to evaluate their feasibility and effectiveness in real settings.
CONFLICTS OF INTEREST
None declared
Conference Material > Video (talk)
van Zandvoort K
MSF Scientific Days International 2023. 2023 June 7; DOI:10.57740/rvhx-fd26
Conference Material > Poster
Monk E, van Zandvoort K, Rao B
MSF Scientific Days International 2023. 2023 June 7