Conference Material > Slide Presentation
Finger F, Mimbu N, Ratnayake R, Meakin S, Bahati JB, et al.
MSF Scientific Day International 2024. 2024 May 16; DOI:10.57740/tC1av3293
Conference Material > Abstract
Finger F, Mimbu N, Ratnayake R, Meakin S, Bahati JB, et al.
MSF Scientific Day International 2024. 2024 May 16; DOI:10.57740/hfok99y
INTRODUCTION
The risk of cholera outbreaks spreading rapidly and extensively is substantial. Case-area targeted interventions (CATI) are based on the premise that early detection can trigger a rapid, localised response in the high-risk radius around case-households to reduce transmission sufficiently to extinguish the outbreak or reduce its spread, as opposed to relying on resource-intensive mass interventions. Current evidence supports intervention in a high-risk spatiotemporal zone of up to 200 m around case- households for 5 days after case presentation. Médecins Sans Frontières (MSF) started delivering CATI to people living within these high-risk rings during outbreaks in the Democratic Republic of the Congo in April 2022. We present the results of a prospective observational study designed to evaluate the CATI strategy, measuring effectiveness, feasibility, timeliness, and resource requirements, and we extract operational learnings.
METHODS
Between April 2022 and April 2023, MSF delivered the holistic CATI package in five cholera-affected regions. The package incorporated key interventions combining household-level water, sanitation, and hygiene measures, health promotion, antibiotic chemoprophylaxis, and single-dose oral cholera vaccination (OCV). We conducted a survey in each ring roughly 3 weeks after the intervention to estimate coverage and uptake of the different components. We measured effectiveness by comparing cholera incidence in the first 30 days between rings with different delays from primary case presentation to CATI implementation, using a Bayesian regression model and adjusting for covariates such as population density, age, and access to water and sanitation.
RESULTS
During the study, four MSF operational sections implemented 118 CATI rings in five sites. The median number of households per ring was 70, the median OCV coverage was 85%, and the median time from presentation of the primary case to CATI implementation and to vaccination was 2 days and 3 days, respectively. These characteristics varied widely across sites and between rings. No secondary cases were observed in 81 (78%) of 104 rings included in the analysis, and we noted a (non- significant) decreasing trend in the number of secondary cases with decreasing delay to CATI implementation, e.g. 1.3 cases [95% CrI 0.01–4.9] for CATI implementation starting within 5 days from primary case presentation, and 0.5 cases [0.03–2.0] for CATI starting within 2 days.
CONCLUSION
Our results show that rapid implementation of CATI with vaccination is feasible in complex contexts. The number of secondary cases was low when CATI was implemented promptly. This highly targeted approach may be an effective strategy to quickly protect people most at risk and is resource- efficient if implemented early to extinguish localised outbreaks before they require mass interventions.
The risk of cholera outbreaks spreading rapidly and extensively is substantial. Case-area targeted interventions (CATI) are based on the premise that early detection can trigger a rapid, localised response in the high-risk radius around case-households to reduce transmission sufficiently to extinguish the outbreak or reduce its spread, as opposed to relying on resource-intensive mass interventions. Current evidence supports intervention in a high-risk spatiotemporal zone of up to 200 m around case- households for 5 days after case presentation. Médecins Sans Frontières (MSF) started delivering CATI to people living within these high-risk rings during outbreaks in the Democratic Republic of the Congo in April 2022. We present the results of a prospective observational study designed to evaluate the CATI strategy, measuring effectiveness, feasibility, timeliness, and resource requirements, and we extract operational learnings.
METHODS
Between April 2022 and April 2023, MSF delivered the holistic CATI package in five cholera-affected regions. The package incorporated key interventions combining household-level water, sanitation, and hygiene measures, health promotion, antibiotic chemoprophylaxis, and single-dose oral cholera vaccination (OCV). We conducted a survey in each ring roughly 3 weeks after the intervention to estimate coverage and uptake of the different components. We measured effectiveness by comparing cholera incidence in the first 30 days between rings with different delays from primary case presentation to CATI implementation, using a Bayesian regression model and adjusting for covariates such as population density, age, and access to water and sanitation.
RESULTS
During the study, four MSF operational sections implemented 118 CATI rings in five sites. The median number of households per ring was 70, the median OCV coverage was 85%, and the median time from presentation of the primary case to CATI implementation and to vaccination was 2 days and 3 days, respectively. These characteristics varied widely across sites and between rings. No secondary cases were observed in 81 (78%) of 104 rings included in the analysis, and we noted a (non- significant) decreasing trend in the number of secondary cases with decreasing delay to CATI implementation, e.g. 1.3 cases [95% CrI 0.01–4.9] for CATI implementation starting within 5 days from primary case presentation, and 0.5 cases [0.03–2.0] for CATI starting within 2 days.
CONCLUSION
Our results show that rapid implementation of CATI with vaccination is feasible in complex contexts. The number of secondary cases was low when CATI was implemented promptly. This highly targeted approach may be an effective strategy to quickly protect people most at risk and is resource- efficient if implemented early to extinguish localised outbreaks before they require mass interventions.
Journal Article > ResearchFull Text
Emerg Infect Dis. 2023 January 1; Volume 29 (Issue 1); 149-153.; DOI:10.3201/eid2901.220641
Hounmanou YM, Njamkepo E, Rauzier J, Gallandat K, Jeandron A, et al.
Emerg Infect Dis. 2023 January 1; Volume 29 (Issue 1); 149-153.; DOI:10.3201/eid2901.220641
Africa’s Lake Tanganyika basin is a cholera hotspot. During 2001–2020, Vibrio cholerae O1 isolates obtained from the Democratic Republic of the Congo side of the lake belonged to 2 of the 5 clades of the AFR10 sublineage. One clade became predominant after acquiring a parC mutation that decreased susceptibility to ciprofloxacin.