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Preprint in English | medRxiv | ID: ppmedrxiv-21261324


BackgroundCamps 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. MethodsTo estimate seroprevalence, we conducted a cross-sectional survey 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. We used a rapid immunologic assay (BIOSYNEX(R) 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, we exhaustively interviewed all households (n=12860) in the camp about deaths occurring from January 2019 through March 2021. ResultsWe included 1206 participants in the seroprevalence study. In total, 8% (95% CI: 6.6%-9.7%) had a positive serologic test. After adjusting for test performance and standardizing on age, we estimated a seroprevalence of 5.8% (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). MSF health centre consultations and hospital admissions decreased by 38% and 37% respectively. ConclusionWe estimated that the number of infected people was 67 times higher than the number of reported cases. Participants aged 50 years or more where 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. Summary BoxO_ST_ABSWhat is already known?C_ST_ABSO_LIAt the early stage of the COVID-19 pandemic, models predicted the risk of a large-scale COVID-19 outbreaks in camps of forcibly displaced populations that would have created excess mortality caused directly by the disease and indirectly by reduced access to care and/or congestion in health facilities. C_LIO_LITo date, this prediction has not materialized in most camps, the lower than expected number of cases and deaths could be attributed to a population characteristics and early implementation of confinement; alternatively, it could be an underestimate caused by limited screening and testing capacity and lack of morbidity and mortality surveillance. C_LIO_LIThe actual impact of COVID-19 on these populations therefore remains an open question. C_LI What are the new findings?O_LIIn Dagahaley camps in Kenya, we estimated that the number of infected people was 67 times higher than the number of reported cases. C_LIO_LIParticipants aged 50 years and over, who are most at risk of severe illness, were among the most affected. C_LIO_LIWe observed an increase in mortality rates during the pandemic, and a decrease in the use of health facilities, which continued despite the easing of restrictions, but access for severe cases was less impacted. C_LI What do the new findings imply?O_LITo our knowledge, this is the first combined survey of COVID-19 seroprevalence and retrospective mortality in a forcibly displaced population living in a camp. C_LIO_LIDespite mitigation measures, the virus has circulated, which should prompt rapid vaccination as most of the population remains susceptible; the collateral effects of the pandemic on access to care must be addressed and public confidence restored in order to limit the risk of excess mortality. C_LIO_LIThe varying situations of forcibly displaced populations living in camps around the world support the need for further research at other sites. C_LI

Preprint in English | medRxiv | ID: ppmedrxiv-20207795


BackgroundA nationwide lockdown was implemented in France on 17 March 2020 to control the COVID-19 pandemic. People living in precarious conditions were relocated by the authorities to emergency shelters, hotels and large venues. Medecins sans Frontieres (MSF) then intervened to provide medical care in several of these locations in Paris and in Seine-Saint-Denis, one of its suburbs, between March and June 2020. A seroprevalence survey was conducted to assess the level of exposure to COVID-19 among the population living in the sites. To our knowledge, this is the first assessment of the impact of the pandemic on populations living in insecure conditions in Europe. MethodsWe conducted a cross-sectional seroprevalence study in the food distribution sites, emergency shelters and workers residences supported by MSF in Paris and Seine-Saint-Denis, to determine the extent of COVID-19 exposure as determined by SARS-CoV2 antibody seropositivity. The detection of SARS-COV2 antibodies in serum was performed at the Institut Pasteur of Paris using two LuLISA (Luciferase-Linked Immunosorbent Assay) assays and a Pseudo Neutralization Test. A questionnaire covering sociodemographic characteristics, living conditions, adherence to sanitary recommendations and symptom manifestations was also completed. We describe here the seroprevalence site by site and identify the risk factors for seropositivity using a multivariable logistic regression model with site random effects. We also investigated associations between seropositivity and symptoms eventually reported. FindingsOverall, 426/818 individuals tested positive in the 14 sites investigated. Seroprevalence varied significantly with the type of site (chi2 p<0.001). It was highest at 88.7% (95%CI 81.8-93.2) among individuals living in workers residences, followed by 50.5% (95%CI 46.3-54.7) in emergency shelters and 27.8 % (95%CI 20.8-35.7) among individuals recruited from the food distribution sites. Seroprevalence also varied significantly between sites of the same type. Among other risk factors, the odds for seropositivity were higher among individuals living in crowded sites (medium: adj. OR 2.7, 95%CI 1.5-5.1, p=0.001; high: adj. OR 3.4, 95%CI 1.7-6.9, p<0.001) compared with individuals from low crowding sites and among those who reported transit accommodation in a gymnasium before the lockdown (adj. OR 3.1, 95%CI 1.2-8.1, p=0.023). More than two-thirds of the seropositive individuals (68.3%; 95%CI 64.2-72.2) did not report any symptoms during the recall period. InterpretationThe results demonstrate rather high exposure to SARS-COV-2 with important variations between study sites. Living in crowded conditions was identified as the most important explanatory factor for differences in levels of exposure. This study describes the key factors which determine the risk of exposure and illustrates the importance of identifying populations at high risk of exposure in order to orient and adapt prevention and control strategies to their specific needs.