Case fatality risk among individuals vaccinated with rVSVΔG-ZEBOV-GP: a retrospective cohort analysis of patients with confirmed Ebola virus disease in the Democratic Republic of the Congo.

BACKGROUND: The rVSVΔG-ZEBOV-GP vaccine constitutes a valuable tool to control Ebola virus disease outbreaks. This retrospective cohort study aimed to assess the protective effect of the vaccine against death among patients with confirmed Ebola virus disease. METHODS: In this retrospective cohort analysis of patients with confirmed Ebola virus disease admitted to Ebola health facilities in the Democratic Republic of the Congo between July 27, 2018, and April 27, 2020, we performed univariate and multivariate analyses to assess case fatality risk and cycle threshold for nucleoprotein according to vaccination status, Ebola virus disease-specific treatments (eg, mAb114 and REGN-EB3), and other risk factors. FINDINGS: We analysed all 2279 patients with confirmed Ebola virus disease. Of these 2279 patients, 1300 (57%) were female and 979 (43%) were male. Vaccination significantly lowered case fatality risk (vaccinated: 25% [106/423] vs not vaccinated: 56% [570/1015]; p<0·0001). In adjusted analyses, vaccination significantly lowered the risk of death compared with no vaccination, with protection increasing as time elapsed from vaccination to symptom onset (vaccinated ≤2 days before onset: 27% [27/99], adjusted relative risk 0·56 [95% CI 0·36-0·82, p=0·0046]; 3-9 days before onset: 20% [28/139], 0·44 [0·29-0·65, p=0·0001]; ≥10 days before onset: 18% [12/68], 0·40 [0·21-0·69; p=0·0022]; vaccination date unknown: 33% [39/117], 0·69 [0·48-0·96; p=0·0341]; and vaccination status unknown: 52% [441/841], 0·80 [0·70-0·91, p=0·0011]). Longer time from symptom onset to admission significantly increased risk of death (49% [1117/2279], 1·03 [1·02-1·05; p<0·0001]). Cycle threshold values for nucleoprotein were significantly higher-indicating lower viraemia-among patients who were vaccinated compared with those who were not vaccinated; the highest difference was observed among those vaccinated 21 days or longer before symptom onset (median 30·0 cycles [IQR 24·6-33·7]) compared with patients who were not vaccinated (21·4 cycles [18·4-25·9], p<0·0001). INTERPRETATION: To our knowledge, this is the first observational study describing the protective effect of rVSVΔG-ZEBOV-GP vaccination against death among patients with confirmed Ebola virus disease admitted to an Ebola health facility. Vaccination was protective against death for all patients, even when adjusted for Ebola virus disease-specific treatment, age group, and time from symptom onset to admission. FUNDING: Médecins Sans Frontières. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Correction: Seroprevalence of SARS-CoV-2 antibodies and retrospective mortality in a refugee camp, Dagahaley, Kenya.

[This corrects the article DOI: 10.1371/journal.pone.0260989.].

Vaccination coverage and adverse events following a reactive vaccination campaign against hepatitis E in Bentiu displaced persons camp, South Sudan.

INTRODUCTION: Hepatitis E (HEV) genotypes 1 and 2 are the common cause of jaundice and acute viral hepatitis that can cause large-scale outbreaks. HEV infection is associated with adverse fetal outcomes and case fatality risks up to 31% among pregnant women. An efficacious three-dose recombinant vaccine (Hecolin) has been licensed in China since 2011 but until 2022, had not been used for outbreak response despite a 2015 WHO recommendation. The first ever mass vaccination campaign against hepatitis E in response to an outbreak was implemented in 2022 in Bentiu internally displaced persons camp in South Sudan targeting 27,000 residents 16-40 years old, including pregnant women. METHODS: We conducted a vaccination coverage survey using simple random sampling from a sampling frame of all camp shelters following the third round of vaccination. For survey participants vaccinated in the third round in October, we asked about the onset of symptoms experienced within 72 hours of vaccination. During each of the three vaccination rounds, passive surveillance of adverse events following immunisation (AEFI) was put in place at vaccination sites and health facilities in Bentiu IDP camp. RESULTS: We surveyed 1,599 individuals and found that self-reported coverage with one or more dose was 86% (95% CI 84-88%), 73% (95% CI 70-75%) with two or more doses and 58% (95% CI 55-61%) with three doses. Vaccination coverage did not differ significantly by sex or age group. We found no significant difference in coverage of at least one dose between pregnant and non-pregnant women, although coverage of at least two and three doses was 8 and 14 percentage points lower in pregnant women. The most common reasons for non-vaccination were temporary absence or unavailability, reported by 60% of unvaccinated people. Passive AEFI surveillance captured few mild AEFI, and through the survey we found that 91 (7.6%) of the 1,195 individuals reporting to have been vaccinated in October 2022 reported new symptoms starting within 72 hours after vaccination, most commonly fever, headache or fatigue. CONCLUSIONS: We found a high coverage of at least one dose of the Hecolin vaccine following three rounds of vaccination, and no severe AEFI. The vaccine was well accepted and well tolerated in the Bentiu IDP camp community and should be considered for use in future outbreak response.

Seroprevalence of SARS-CoV-2 antibodies and retrospective mortality in two African settings: Lubumbashi, Democratic Republic of the Congo and Abidjan, Côte d'Ivoire.

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.

Seroprevalence of anti-SARS-CoV-2 antibodies among blood donors from December 2020 to June 2021 in Koutiala district, Mali.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus associated with coronavirus disease (COVID-19). At the time of the study, little data on the level of exposure of the population in Koutiala district in Mali to SARS-CoV-2 was available. Although blood donors are not representative of the general population, a COVID-19 seroprevalence estimate in this population was intended to assess the extent of community transmission, serve as a health alert system, and help guide the public health response. We measured seroprevalence of anti-SARS-CoV-2 antibodies using NG-Biotech SARS-Cov-2 RDT and ECLIA test between January and June 2020. This is a cross-sectional study of volunteer blood donors aged 18 to 60 years, independent of any previous COVID-19 disease. A stratified analysis of seroprevalence by month of sample collection and a comparison of the results of the NG-Biotech SARS-Cov-2 RDT with those of the ECLIA test was performed. The overall prevalence of antibodies to SARS-Cov-2 virus assessed by the NG-Biotech SARS-Cov-2 RDT was 24.6% (95% CI 21.8-27.4) and by the ECLIA test was 70.2 (95% CI 64.9-75.5). Both estimates remained relatively stable over the study period. We observed SARS-CoV-2 exposure much higher than indicated by case-based surveillance. The national surveillance system, as it was, was not able to detect variations in incidence, and as such, we do not recommend it as an alert system. However, the discrepancy between the results of the rapid test and the ECLIA test shows that further research is required to assess the validity of these test before a more solid conclusion can be drawn it their use in surveillance.

Effect of large-scale mass drug administration for malaria on mortality and morbidity in Angumu health zone, Ituri, Democratic Republic of Congo.

BACKGROUND: Angumu health zone in Ituri, Democratic Republic of Congo, is a highly malaria-endemic area with an overburdened health system and hosting internally displaced persons (IDP). The World Health Organization recommends mass drug administration (MDA) for malaria in complex emergencies. Therefore, three MDA rounds were implemented by Ministry of Public Health and Médecins sans Frontières from September 2020 to January 2021 in four health areas selected for epidemiological (high malaria incidence) and logistic reasons. Reported mortality and morbidity were compared in locations where MDA has been performed and locations where it has not. METHODS: A non-randomized controlled population-based retrospective mortality survey was conducted in March 2021. Two-stage cluster sampling was used in villages; all IDP sites were surveyed with systematic random sampling. The main (mortality rates) and secondary (morbidity) outcomes were estimated and compared between locations where MDA had been conducted and where it had not, using mixed Poisson and binomial regression models respectively. RESULTS: Data was collected for 2554 households and 15470 individuals, of whom 721 died in the 18-month recall period. The under-five mortality rate (U5MR) decreased in the locations where MDA had been implemented from 2.32 [1.48-3.16] "before" the MDA to 1.10 [0.5-1.71] deaths/10,000 children under 5 years/day "after", whereas it remained stable from 2.74 [2.08-3.40] to 2.67 [1.84-3.50] deaths/10,000 children/day in the same time periods in locations where MDA had not been implemented. The U5MR and malaria-specific mortality was significantly higher in non-MDA locations after MDA was implemented (aRR = 2.17 [1.36-3.49] and 2.60 [1.56-4.33], respectively, for all-cause and malaria-specific mortality among children < 5 years). Morbidity (all age and < 5 years, all cause or malaria-specific) appeared lower in MDA locations 2.5 months after last round: reported malaria-specific morbidity was 14.7% [11-18] and 25.0% [19-31] in villages and IDP sites where MDA had been implemented, while it was 30.4% [27-33] and 49.3% [45-54] in villages and IDP sites with no MDA. CONCLUSIONS: Despite traditional limitations associated with non-randomized controlled retrospective surveys, the documented sharp decrease of under-5 mortality and morbidity shows that MDA has the potential to become an important malaria-control tool in emergency settings. Based on these results, new MDA rounds, along with indoor residual spraying campaigns, have been planned in the health zone in 2022. A set of surveys will be conducted before, during and after these rounds to confirm the effect observed in 2021 and assess its duration.

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

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.

SARS-CoV-2 Antibody Prevalence and Population-Based Death Rates, Greater Omdurman, Sudan.

In a cross-sectional survey in Omdurman, Sudan, during March-April 2021, we estimated that 54.6% of the population had detectable severe acute respiratory syndrome coronavirus 2 antibodies. Overall population death rates among those >50 years of age increased 74% over the first coronavirus disease pandemic year.

Snakebite epidemiology in humans and domestic animals across the Terai region in Nepal: a multicluster random survey.

BACKGROUND: Each year, 2 million people worldwide are bitten by snakes, resulting in an estimated 81 000-138 000 deaths. WHO has added snakebite envenoming to the list of neglected tropical diseases, highlighting the need for stronger epidemiological evidence in endemic countries, such as Nepal. METHODS: We conducted a cross-sectional survey in villages randomly geospatially selected from aerial images from across the Nepal's Terai lowlands region (excluding towns and cities). We collected data between Nov 30, 2018 and May 7, 2019, and analysed snakebite incidence rates and outcomes in humans and domestic animals. FINDINGS: Among 63 454 human participants living in 13 879 households (249 villages), 166 were bitten by a snake over the previous 12 months; 48·8% were envenomed and 7·8% died. This corresponded to an annual crude incidence rate of 262 snakebites (adjusted incidence of 251·1 [95% CI 201·7-312·6]) and 20 deaths (22·4 [11·9-42·1]) per 100 000 people, extrapolating to 26 749-37 661 yearly bitten people and 2386-3225 deaths. Bitten people had a median age of 30 years (IQR 20-45) and with available data, 64% were female. Children younger than 15 years (n=6; 46%) and females (n=10; 77%) were disproportionately affected among the 13 people who died. The incidence was higher in the Eastern region, and mortality was higher in the Central region. Of 183 949 animals, owners reported 144 snakebites, with an annual incidence rate of 42-202 per 100 000 and mortality of 79-100%, varying by animal type. Spatial and seasonal incidence were similar in humans and in animals. INTERPRETATION: This study provides the first epidemiological estimates of snakebite envenoming in humans and domestic animals across Nepal's Terai lowlands. It was also the first to use a community-based, transdisciplinary, and One Health design. These findings call for a strengthening of preventive measures and better access to life-saving treatments. FUNDING: Swiss National Science Foundation project 315130_176271 (SNAKE-BYTE).

Seroprevalence of SARS-CoV-2 antibodies and retrospective mortality in a refugee camp, Dagahaley, Kenya.

BACKGROUND: Camps of forcibly displaced populations are considered to be at risk of large COVID-19 outbreaks. Low screening rates and limited surveillance led us to conduct a study in Dagahaley camp, located in the Dadaab refugee complex in Kenya to estimate SARS-COV-2 seroprevalence and, mortality and to identify changes in access to care during the pandemic. METHODS: To estimate seroprevalence, a cross-sectional survey was conducted among a sample of individuals (n = 587) seeking care at the two main health centres and among all household members (n = 619) of community health workers and traditional birth attendants working in the camp. A rapid immunologic assay was used (BIOSYNEX® COVID-19 BSS [IgG/IgM]) and adjusted for test performance and mismatch between the sampled population and that of the general camp population. To estimate mortality, all households (n = 12860) were exhaustively interviewed in the camp about deaths occurring from January 2019 through March 2021. RESULTS: In total 1206 participants were included in the seroprevalence study, 8% (95% CI: 6.6%-9.7%) had a positive serologic test. After adjusting for test performance and standardizing on age, a seroprevalence of 5.8% was estimated (95% CI: 1.6%-8.4%). The mortality rate for 10,000 persons per day was 0.05 (95% CI 0.05-0.06) prior to the pandemic and 0.07 (95% CI 0.06-0.08) during the pandemic, representing a significant 42% increase (p<0.001). Médecins Sans Frontières health centre consultations and hospital admissions decreased by 38% and 37% respectively. CONCLUSION: The number of infected people was estimated 67 times higher than the number of reported cases. Participants aged 50 years or more were among the most affected. The mortality survey shows an increase in the mortality rate during the pandemic compared to before the pandemic. A decline in attendance at health facilities was observed and sustained despite the easing of restrictions.

Novel transdisciplinary methodology for cross-sectional analysis of snakebite epidemiology at national scale.

BACKGROUND: Worldwide, it is estimated that snakes bite 4.5-5.4 million people annually, 2.7 million of which are envenomed, and 81,000-138,000 die. The World Health Organization reported these estimates and recognized the scarcity of large-scale, community-based, epidemiological data. In this context, we developed the "Snake-Byte" project that aims at (i) quantifying and mapping the impact of snakebite on human and animal health, and on livelihoods, (ii) developing predictive models for medical, ecological and economic indicators, and (iii) analyzing geographic accessibility to healthcare. This paper exclusively describes the methodology we developed to collect large-scale primary data on snakebite in humans and animals in two hyper-endemic countries, Cameroon and Nepal. METHODOLOGY/PRINCIPAL FINDINGS: We compared available methods on snakebite epidemiology and on multi-cluster survey development. Then, in line with those findings, we developed an original study methodology based on a multi-cluster random survey, enhanced by geospatial, One Health, and health economics components. Using a minimum hypothesized snakebite national incidence of 100/100,000/year and optimizing design effect, confidence level, and non-response margin, we calculated a sample of 61,000 people per country. This represented 11,700 households in Cameroon and 13,800 in Nepal. The random selection with probability proportional to size generated 250 clusters from all Cameroonian regions and all Nepalese Terai districts. Our household selection methodology combined spatial randomization and selection via high-resolution satellite images. After ethical approval in Switerland (CCER), Nepal (BPKIHS), and Cameroon (CNERSH), and informed written consent, our e-questionnaires included geolocated baseline demographic and socio-economic characteristics, snakebite clinical features and outcomes, healthcare expenditure, animal ownership, animal outcomes, snake identification, and service accessibility. CONCLUSIONS/SIGNIFICANCE: This novel transdisciplinary survey methodology was subsequently used to collect countrywide snakebite envenoming data in Nepal and Cameroon. District-level incidence data should help health authorities to channel antivenom and healthcare allocation. This methodology, or parts thereof, could be easily adapted to other countries and to other Neglected Tropical Diseases.

A telephone based assessment of the health situation in the far north region of Cameroon.

BACKGROUND: In 2017, Field access was considerably limited in the Far North region of Cameroon due to the conflict. Médecins Sans Frontieres (MSF) in collaboration with Ministry of health needed to estimate the health situation of the populations living in two of the most affected departments of the region: Logone-et-Chari and Mayo-Sava. METHODS: Access to health care and mortality rates were estimated through cell phone interviews, in 30 villages (clusters) in each department. Local Community Health Workers (CHWs) previously collected all household phone numbers in the selected villages and nineteen were randomly selected from each of them. In order to compare telephone interviews to face-to-face interviews for estimating health care access, and mortality rates, both methods were conducted in parallel in the town of Mora in the mayo Sava department. Access to food was assessed through push messages sent by the three main mobile network operators in Cameroon. Additionally, all identified legal health care facilities in the area were interviewed by phone to estimate attendance and services offered before the conflict and at the date of the survey. RESULTS: Of a total of 3423 households called 43% were reached. Over 600,000 push messages sent and only 2255 were returned. We called 43 health facilities and reached 34 of them. In The town of Mora, telephone interviews showed a Crude Mortality Rate (CMR) at 0.30 (CI 95%: 0.16-0.43) death per 10,000-person per day and home visits showed a CMR at 0.16 (0.05-0.27), most other indicators showed comparable results except household composition (more Internally Displaced Persons by telephone). Phone interviews showed a CMR at 0.63 (0.29-0.97) death per 10,000-person per day in Logone-et-Chari, and 0.30 (0.07-0.50) per 10,000-person per day in Mayo-Sava. Among 86 deaths, 13 were attributed to violence (15%), with terrorist attacks being explicitly mentioned for seven deaths. Among 29 health centres, 5 reported being attacked and vandalized; 3 remained temporally closed; Only 4 reported not being affected. CONCLUSION: Telephone interviews are feasible in areas with limited access, although special attention should be paid to the initial collection of phone numbers. The use of text messages to collect data was not satisfactory is not recommended for this purpose. Mortality in Logone-et-Chari and Mayo-Sava was under critical humanitarian thresholds although a considerable number of deaths were directly related to the conflict.

Measles seroprevalence after reactive vaccination campaigns during the 2015 measles outbreak in four health zones of the former Katanga Province, Democratic Republic of Congo.

BACKGROUND: Measles continues to circulate in the Democratic Republic of Congo, and the country suffered from several important outbreaks over the last 5 years. Despite a large outbreak starting in the former province of Katanga in 2010 and the resulting immunization activities, another outbreak occurred in 2015 in this same region. We conducted measles seroprevalence surveys in four health zones (HZ) in the former Katanga Province in order to assess the immunity against measles in children 6 months to 14 years after the 2015 outbreak. METHODS: We conducted multi-stage cluster surveys stratified by age group in four HZs, Kayamba, Malemba-Nkulu, Fungurume, and Manono. The age groups were 6-11 months, 12-59 months, and 5-14 years in Kayamba and Malemba-Nkulu, 6-59 months and 5-14 years in Manono and Fungurume. The serological status was measured on dried capillary blood spots collected systematically along with vaccination status (including routine Extended Program of Immunization (EPI), and supplementary immunization activities (SIAs)) and previous self-reported history of suspected measles. RESULTS: Overall seroprevalence against measles was 82.7% in Kayamba, 97.6% in Malemba-Nkulu, 83.2% in Manono, and 74.4% in Fungurume, and it increased with age in all HZs. It was 70.7 and 93.8% in children 12-59 months in Kayamba and Malemba-Nkulu, and 49.8 and 64.7% in children 6-59 months in Fungurume and Manono. The EPI coverage was low but varied across HZ. The accumulation of any type of vaccination against measles resulted in an overall vaccine coverage (VC) of at least 85% in children 12-59 months in Kayamba and Malemba-Nkulu, 86.1 and 74.8% in children 6-59 months in Fungurume and Manono. Previous measles infection in 2015-early 2016 was more frequently reported in children aged 12-59 months or 6-59 months (depending on the HZ). CONCLUSION: The measured seroprevalence was consistent with the events that occurred in these HZs over the past few years. Measles seroprevalence might prove a valuable source of information to help adjust the timing of future SIAs and prioritizing support to the EPI in this region as long as the VC does not reach a level high enough to efficiently prevent epidemic flare-ups.

Nagaland health assessment: High mortality rates and difficulty accessing essential health services in Lahe Township, Republic of the Union of Myanmar.

INTRODUCTION: Lahe Township belongs to Myanmar`s Naga Self-administered Zone, which is one of the most remote and mountainous areas in Myanmar. However, the limited health data available for the region suggests that there could be neglected health needs that require attention. The purpose of this study was to assess the health status of the population of Lahe Township. METHODS: A cross-sectional study design incorporating a two-stage cluster sampling methodology recommended by the WHO was used to conduct a household level survey. In the first stage, 30 village clusters were selected from all villages situated in the Lahe Township through systematic sampling with probability of selection proportional to the population size of each village based on the 2014 Myanmar census. In the second stage, a GPS-based sampling method was used to select 30 households within a village cluster. The head of the household completed the survey for all members of the household. Questionnaires inquired about maternal health, mortality, morbidities, childhood nutritional status, access to health care, and water & sanitation. The resulting data was stratified by urban/rural status. RESULTS: Data was collected on 5,929 individuals living in 879 households, of which 993 individuals (16.7%) were children 5 years old or younger. The median age was 18.0 (IQR 8.0-35.0). Children 15 years old or younger represented 44.7% of the population. 19.8% of households reported at least 1 household member sick during the previous 30 days. The crude mortality rate per 10,000 people per day was 0.58 (95% CI: 0.48-0.69). The under 5 mortality per 10,000 people per day was 0.74 (95% CI: 0.50-1.06). Only 46.7% of households could access a hospital if there was a need. CONCLUSION: Our results demonstrate a high rate of mortality and the inability to access healthcare in Lahe Township, which should be addressed to prevent further deterioration of health.

A post-conflict vaccination campaign, Central African Republic.

OBJECTIVE: To rapidly increase childhood immunization through a preventive, multi-antigen, vaccination campaign in Mambéré-Kadéï prefecture, Central African Republic, where a conflict from 2012 to 2015 reduced vaccination coverage. METHODS: The three-round campaign took place between December 2015 and June 2016 using: (i) oral poliomyelitis vaccine (OPV); (ii) combined diphtheria, tetanus and pertussis (DTP) vaccine, Haemophilus influenza type B (Hib) and hepatitis B (DTP-Hib-hepatitis B) vaccine; (iii) pneumococcal conjugate vaccine (PCV); (iv) measles vaccine; and (v) yellow fever vaccine. Administrative data were collected on vaccines administered by age group and vaccination coverage surveys were carried out before and after the campaign. FINDINGS: Overall, 294 054 vaccine doses were administered. Vaccination coverage for children aged 6 weeks to 59 months increased to over 85% for the first doses of OPV, DTP-Hib-hepatitis B vaccine and PCV and, in children aged 9 weeks to 59 months, to over 70% for the first measles vaccine dose. In children aged 6 weeks to 23 months, coverage of the second doses of OPV, DTP-Hib-hepatitis B vaccine and PCV was over 58% and coverage of the third doses of OPV and DTP-Hib-hepatitis B vaccine was over 20%. Moreover, 61% (5804/9589) of children aged 12 to 23 months had received two PCV doses and 90% (25933/28764) aged 24 to 59 months had received one dose. CONCLUSION: A preventive, multi-antigen, vaccination campaign was effective in rapidly increasing immunization coverage in a post-conflict setting. To sustain high coverage, routine immunization must be reinforced.

Risk factors for measles mortality and the importance of decentralized case management during an unusually large measles epidemic in eastern Democratic Republic of Congo in 2013.

In 2013, a large measles epidemic occurred in the Aketi Health Zone of the Democratic Republic of Congo. We conducted a two-stage, retrospective cluster survey to estimate the attack rate, the case fatality rate, and the measles-specific mortality rate during the epidemic. 1424 households containing 7880 individuals were included. The estimated attack rate was 14.0%, (35.0% among children aged <5 years). The estimated case fatality rate was 4.2% (6.1% among children aged <5 years). Spatial analysis and linear regression showed that younger children, those who did not receive care, and those living farther away from Aketi Hospital early in the epidemic had a higher risk of measles related death. Vaccination coverage prior to the outbreak was low (76%), and a delayed reactive vaccination campaign contributed to the high attack rate. We provide evidences suggesting that a comprehensive case management approach reduced measles fatality during this epidemic in rural, inaccessible resource-poor setting.