Conference Material > Abstract
Eisenhauer C
Epicentre Scientific Day 2024. 23 May 2024
BACKGROUND
Outbreak alert systems can offset the severity of measles epidemics by minimising response delays. Existing systems, however, are often too sensitive to be practical when identifying areas for reactive interventions. To redress this challenge, we present a simple alternative system that combines a weekly and triweekly suspected case threshold. First evaluated in the DRC in 2022, here we extend the evaluation of this system to the context of Niger.
METHODS
A large number of threshold combinations were evaluated against indicators of cases captured by intervention and false alert risk. Combinations were evaluated against admin 2 level surveillance data from the DRC and Niger from 2015-2024. Performance was then compared to standard recommendations from the WHO and MSF.
RESULTS
The two example countries have distinct epidemic profiles, with the DRC exhibiting mas epidemics and Niger showing strong annual seasonality. In both settings, the proposed alternative alert system outperformed the existing WHO and MSF recommendation. The WHO recommendation, which is triggered by four suspected cases occuring within one month in a given locale (here, admin level 2), performs similarly to the proposed alternative when selecting the most sensitive of threshold combinations. The MSF recommendation, which is triggered by a raw increase in number of cases for three consecutive weeks, performed markedly worse, capturing 50% or less of cases. This poor performance is predominantly attributable to the high volatility of weekly measles surveillance data.
CONCLUSION
This analysis presents a simple evidence based alert system to improve measles outbreak response. It has been assessed in two countries, Niger and the DRC, and found to outperform standard recommendations. At present the system is available for use in both countries via their respective surveillance dashboards. Ongoing work is being conducted to evaluate the system in settings with additional epidemic profiles, including areas with low burden and areas with poor surveillance.
Outbreak alert systems can offset the severity of measles epidemics by minimising response delays. Existing systems, however, are often too sensitive to be practical when identifying areas for reactive interventions. To redress this challenge, we present a simple alternative system that combines a weekly and triweekly suspected case threshold. First evaluated in the DRC in 2022, here we extend the evaluation of this system to the context of Niger.
METHODS
A large number of threshold combinations were evaluated against indicators of cases captured by intervention and false alert risk. Combinations were evaluated against admin 2 level surveillance data from the DRC and Niger from 2015-2024. Performance was then compared to standard recommendations from the WHO and MSF.
RESULTS
The two example countries have distinct epidemic profiles, with the DRC exhibiting mas epidemics and Niger showing strong annual seasonality. In both settings, the proposed alternative alert system outperformed the existing WHO and MSF recommendation. The WHO recommendation, which is triggered by four suspected cases occuring within one month in a given locale (here, admin level 2), performs similarly to the proposed alternative when selecting the most sensitive of threshold combinations. The MSF recommendation, which is triggered by a raw increase in number of cases for three consecutive weeks, performed markedly worse, capturing 50% or less of cases. This poor performance is predominantly attributable to the high volatility of weekly measles surveillance data.
CONCLUSION
This analysis presents a simple evidence based alert system to improve measles outbreak response. It has been assessed in two countries, Niger and the DRC, and found to outperform standard recommendations. At present the system is available for use in both countries via their respective surveillance dashboards. Ongoing work is being conducted to evaluate the system in settings with additional epidemic profiles, including areas with low burden and areas with poor surveillance.
Conference Material > Abstract
Langendorf C, Nikolay B
Epicentre Scientific Day 2024. 23 May 2024
BACKGROUND
While case confirmation is most of the time not necessary for case management decisions– the measles outbreak response relies on the timely biological confirmation of outbreaks to facilitate a vaccination response. Seroprevalence estimates, on the other hand, can help plan vaccination activities or evaluate them, by quantifying immunization levels in the population. In remote areas where transport of serum or plasma samples is challenging, we ideally would like to use dried blood spots (DBS) which are easy to collect, easy to transport, and theoretically stable in time and temperature. However, the practical use of DBS under field conditions is not as easy as we expect. Based on different examples of measles surveys in the DRC and Niger, we will describe the challenges we are facing regarding interpretation of serology results from DBS for both measles
biological confirmation and seroprevalence surveys.
RESULTS AND DISCUSSION
In the DRC, for biological confirmation , the sensitivity of DBS samples compared to plasma decreases with transport delays and is lower in remote settings. Measles seroprevalence based on DBS was lower than expected, raising questions about the use of the recommended seropositivity threshold and the correlation with seroprotection after vaccination. In Niger, we found that a good quality DBS can be obtain under field conditions, and an adjustment factor for DBS compared to serum is needed but may vary between settings.
CONCLUSION
Serology on DBS is the most acceptable procedure so far for biological confirmation of measles cases and seroprevalence. However, additional investigations are needed to better standardize, test, and interpret DBS samples to help making the most appropriate operational decisions.
While case confirmation is most of the time not necessary for case management decisions– the measles outbreak response relies on the timely biological confirmation of outbreaks to facilitate a vaccination response. Seroprevalence estimates, on the other hand, can help plan vaccination activities or evaluate them, by quantifying immunization levels in the population. In remote areas where transport of serum or plasma samples is challenging, we ideally would like to use dried blood spots (DBS) which are easy to collect, easy to transport, and theoretically stable in time and temperature. However, the practical use of DBS under field conditions is not as easy as we expect. Based on different examples of measles surveys in the DRC and Niger, we will describe the challenges we are facing regarding interpretation of serology results from DBS for both measles
biological confirmation and seroprevalence surveys.
RESULTS AND DISCUSSION
In the DRC, for biological confirmation , the sensitivity of DBS samples compared to plasma decreases with transport delays and is lower in remote settings. Measles seroprevalence based on DBS was lower than expected, raising questions about the use of the recommended seropositivity threshold and the correlation with seroprotection after vaccination. In Niger, we found that a good quality DBS can be obtain under field conditions, and an adjustment factor for DBS compared to serum is needed but may vary between settings.
CONCLUSION
Serology on DBS is the most acceptable procedure so far for biological confirmation of measles cases and seroprevalence. However, additional investigations are needed to better standardize, test, and interpret DBS samples to help making the most appropriate operational decisions.
Conference Material > Poster
Salou H, Nikolay B
Epicentre Scientific Day 2024. 23 May 2024
Français
Conference Material > Poster
Mamaty AA, Atti S, Sani KA, Tonamou G, Ciglenecki I, et al.
MSF Scientific Day International 2024. 16 May 2024; DOI:10.57740/QLiHOZ
Conference Material > Poster
Sheikh Mohamed A, Ilyas A, Abbas A, Avochi S, Kihara M, et al.
MSF Paediatric Days 2024. 3 May 2024; DOI:10.57740/fDNraEM
Conference Material > Slide Presentation
Lau DK, Seebacher S, Abdi AM, Bishar S, Nur MB, et al.
MSF Paediatric Days 2024. 3 May 2024; DOI:10.57740/ld1iLMav4
Conference Material > Poster
Al-Zubairi TA, Mohammed NA, Al-Soumal MH
MSF Paediatric Days 2024. 3 May 2024; DOI:10.57740/sUVsrUbdz
Conference Material > Abstract
Lau DK, Seebacher S, Abdi AM, Bishar S, Nur MB, et al.
MSF Paediatric Days 2024. 3 May 2024; DOI:10.57740/eyJwVt4rop
BACKGROUND AND OBJECTIVES
Kismayo is a city in southern Somalia and the capital of Jubaland State. In 2020, the Jubaland State Ministry of Health (MoH) recorded 1094 measles cases: an 8.2-fold increase from 2019. This study sought to estimate measles disease burden and measles vaccination coverage during the 2020-2021 outbreak, while further identifying key barriers and facilitators to measles vaccination and care.
METHODS
We utilised a sequential mixed-method approach with two phases of data collection. Phase one involved a cross-sectional household survey with a standard questionnaire while phase two included key informant interviews and focus group discussions with community members, health care workers and vaccination program administrators.
RESULTS
Of 6664 individuals, 338 measles cases were recorded during the two-year recall period, giving an attack rate of 5% (95%CI:4-5). 17 measles deaths were reported, giving a case fatality ratio of 4% (95%CI:2-6). Measles-specific mortality was 0.04 deaths/day/10000 population (95%CI:0.02-0.05). Initially, 50% of vaccine-eligible children had one or more doses of measles containing vaccine (MCV) and this rose to 69% by the end of the recall period. Thematic analysis led to the grouping of qualitative data into two overarching themes: sociocultural factors and health system factors. Regarding sociocultural factors, respondents gave insights on community measles knowledge and care practices, social responsibility for prevention, security challenges and measles-related rumours. Regarding health system factors, respondents spoke about challenges with health service management and shortcomings in the implementation of the expanded programme on immunisation (EPI) and mass vaccination campaigns.
CONCLUSIONS
Our results show that measles represents a serious health burden for the Kismayo population and that MCV coverage is well below the 95% target for herd immunity. We recommend developing a population-specific approach to risk communication and community engagement, expanding measles care, increasing accessibility for EPI services in health facilities and mobile clinics, and developing improved programmatic strategies for mass vaccination campaigns.
Kismayo is a city in southern Somalia and the capital of Jubaland State. In 2020, the Jubaland State Ministry of Health (MoH) recorded 1094 measles cases: an 8.2-fold increase from 2019. This study sought to estimate measles disease burden and measles vaccination coverage during the 2020-2021 outbreak, while further identifying key barriers and facilitators to measles vaccination and care.
METHODS
We utilised a sequential mixed-method approach with two phases of data collection. Phase one involved a cross-sectional household survey with a standard questionnaire while phase two included key informant interviews and focus group discussions with community members, health care workers and vaccination program administrators.
RESULTS
Of 6664 individuals, 338 measles cases were recorded during the two-year recall period, giving an attack rate of 5% (95%CI:4-5). 17 measles deaths were reported, giving a case fatality ratio of 4% (95%CI:2-6). Measles-specific mortality was 0.04 deaths/day/10000 population (95%CI:0.02-0.05). Initially, 50% of vaccine-eligible children had one or more doses of measles containing vaccine (MCV) and this rose to 69% by the end of the recall period. Thematic analysis led to the grouping of qualitative data into two overarching themes: sociocultural factors and health system factors. Regarding sociocultural factors, respondents gave insights on community measles knowledge and care practices, social responsibility for prevention, security challenges and measles-related rumours. Regarding health system factors, respondents spoke about challenges with health service management and shortcomings in the implementation of the expanded programme on immunisation (EPI) and mass vaccination campaigns.
CONCLUSIONS
Our results show that measles represents a serious health burden for the Kismayo population and that MCV coverage is well below the 95% target for herd immunity. We recommend developing a population-specific approach to risk communication and community engagement, expanding measles care, increasing accessibility for EPI services in health facilities and mobile clinics, and developing improved programmatic strategies for mass vaccination campaigns.
Journal Article > CommentaryFull Text
Lancet. 29 April 2024; Volume 403 (Issue 10439); 1825-1827.; DOI:10.1016/S0140-6736(24)00749-9
Coulborn RM, Danet C, Alsalhani A
Lancet. 29 April 2024; Volume 403 (Issue 10439); 1825-1827.; DOI:10.1016/S0140-6736(24)00749-9
Worldwide, more than 99% of the burden of measles infections and deaths affects populations in low-income and middle-income countries. Measles accounts for 3% of the global mortality of children younger than five years, constituting 90% of deaths from measles, and rubella is the main vaccine-preventable cause of birth defects. Vaccine coverage, both through routine immunisation and supplementary immunisation activities, remains below targets for measles elimination, with considerable heterogeneity between and within countries.
Journal Article > CommentaryFull Text
Confl Health. 1 February 2024; Volume 18 (Issue 1); 14.; DOI:10.1186/s13031-024-00569-6
Van Brusselen D, Dubois AH, Bindu LK, Moluh Z, Nzomukunda Y, et al.
Confl Health. 1 February 2024; Volume 18 (Issue 1); 14.; DOI:10.1186/s13031-024-00569-6
The COVID-19 pandemic and vaccine hesitancy are not the only causes of the increase in measles cases in low- and middle-income countries. Measles epidemics, like the recent one in eastern DRC, are often quickly halted by mass vaccination in ‘easy to reach’ refugee camps. However, governmental and humanitarian actors fail to respond effectively in ‘hard-to-reach’ areas like Masisi, frequently limiting themselves to more accessible areas close to big cities.