key: cord-292600-mgvrbfzd authors: Ly, T. D. A.; Hoang, V. T.; Goumballa, N.; Louni, M.; Canard, N.; Dao, T. L.; Medkour, H.; Borg, A.; Bardy, K.; Esteves-Vieira, V.; Filosa, V.; Davoust, B.; Mediannikov, O.; Fournier, P.-E.; Raoult, D.; Gautret, P. title: Screening of SARS-CoV-2 among homeless people, asylum seekers and other people living in precarious conditions in Marseille, France, March April 2020. date: 2020-05-11 journal: nan DOI: 10.1101/2020.05.05.20091934 sha: doc_id: 292600 cord_uid: mgvrbfzd Surveillance of SARS-CoV-2 infection among sheltered homeless and other vulnerable people might provide the information needed to prevent its spread within accommodation centres. In March-April, we enrolled 411 homeless individuals, 77 asylum-seekers, 58 people living in precarious conditions, and 152 employees working in these accommodation centres and collected nasal samples. SARS-CoV-2 carriage was assessed by quantitative PCR. Overall, 49 (7.0%) people were positive for SARS-CoV-2, including 37 homeless individuals (of 411, 9.0%), 12 employees (of 152, 7.9%). SARS-CoV-2 positivity correlated with symptoms, although 51% of positive patients did not report respiratory symptoms or fever. Among homeless people, being young (18-34 years) (OR: 3.83 [1.47-10.0], p=0.006) and being housed in one specific shelter (OR: 9.13 [4.09-20.37], p<0.0001) were independent factors associated with the SARS-CoV-2 positivity rates (11.4% and 20.6%, respectively). The survey reveals the role of collective housing in relation to viral transmission within centres. Since March 2020, the coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread over more than 200 countries and territories worldwide (1) . Homeless people are a vulnerable group who may potentially be exposed to this infection and have potentially more severe outcomes than in the general population, due to their poor living conditions, the higher prevalence of comorbidity, and mental and physical conditions impaired by substance or alcohol abuse (2) (3) (4) (5) (6) . Crowded conditions in shelters without specific preventive measures could facilitate viral transmission (7, 8) . In several U.S. cities, 1,192 residents and 313 staff members were tested in 19 homeless shelters in March-April and high rates of SARS-CoV-2 carriage were observed in residents (25%) and staff members (11%) (9, 10); the prevalence was also reported to be 9.7-15.5% and 13.3%-14.8% among residents and staff members in within 3 homeless shelters in Washington, respectively (11). This raised concerns that the virus may be widely transmitted within homeless shelters, even when infection control vigilance is high. Over the past two decades, our institute has carried out a large number of surveys among homeless persons within two shelters (A and B) in Marseille, France. We observed a high prevalence of respiratory symptoms and signs (12) and high carriage rates of both respiratory viruses (13) and bacteria (14), suggesting that SARS-CoV-2 infection might also be frequent in this population. Based on the preliminary information that some homeless persons from these two shelters presented with COVID-19 symptoms, we organised a screening campaign in collaboration with the staff in charge of these shelters. We subsequently received other requests for screening from several accommodation centres specialising in housing vulnerable people. In this study, we present the results of SARS-CoV-2 screening campaigns conducted among sheltered homeless individuals, in comparison with asylum-seekers, other persons living in precarious conditions, and employees working in the accommodation centres. We also investigated the role of potential risk factors for virus carriage among the homeless population. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted May 11, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted May 11, 2020. Participants were encouraged by the management staff of the facilities to get tested and were then recruited on a voluntary basis. They were systematically asked to provide basic demographic information (sex, age, country of origin), chronic conditions, and any respiratory symptoms or fever in the two weeks prior to sampling. Body temperature was measured using a forehead infrared thermometer. Nasal samples were systematically collected on transport media using Sigma Transwabs (Medical Wire, Corsham, United Kingdom). For self-sampling, participants were invited to insert the swab into their nostrils (about 2 cm). If individuals were unable to perform selfsampling, trained investigators carried out the sampling. Specimens were immediately processed for SARS-CoV-2 PCR testing. Homeless peoples' pets were also tested with the approval of their owner and their nasal swabs were collected by vets. Real-time reverse transcription-PCR amplification was used to confirm the presence of SARS-CoV-2 RNA targeting the gene coding for the envelope (E) protein, as previously described (15). Results were considered positive when the cycle threshold (CT) value of real-time PCR was ≤ 35. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.05.20091934 doi: medRxiv preprint Statistical procedures were performed using STATA 11.1 software (StataCorp LLC, USA). Percentage differences were tested using Pearson's chi-square or Fisher's exact tests when appropriate. Means of quantitative data were compared using Student's t-test. A p value <0.05 was considered statistically significant. A separate multivariate logistical regression analysis was used to identify independent risk factors for SARS-CoV-2 carriage prevalence among all individuals and in selected groups (when positive cases were found). The results were presented by percentages and odd ratio (OR) with 95% confidence interval (95%CI). The initial model included variables presenting a p-value <0.2. The stepwise regression procedure and likelihoodratio tests were applied to determine the final model. Overall, 885 individuals were present in the various facilities at the time of enrolment, including 716 residents and 169 employees ( Table 2) . A total of 698 (78.9%) subjects agreed to be tested, including 411/698 homeless people (58.9%), 58 non-homeless people living in precarious conditions (8.3%), 77 asylum-seekers (11.0%), and 152 employees (21.8%). Overall, 38.7% were enrolled before C14, 45.9% between C14 and C20, and 15.4% at C21 and later (Table 1 , 3). The overall acceptation rate of SARS-CoV-2 testing varied significantly according to the housing facility, ranging from 41.7 to 91.7%. The overall acceptation rate among homeless individuals was 74.6% and was significantly lower than that of employees working in the homeless centres (88.7%, p=0.0008). The acceptance rate among people housed in other facilities, varied from 75.5 to 100% and tented to be lower than that of employees in these facilities. The socio-demographic characteristics of the different populations are presented in Table 3 . The male to female gender ratio was 3:1 and the median age was 35.0 years (ranging from 0 to 91 years) with significant variations among different populations. A male predominance was observed among homeless persons and asylum seekers. Children ≤ 15 years old accounted for 7.5% of all residents. Two-thirds of individuals were migrants. A predominance of African origin was found . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.05.20091934 doi: medRxiv preprint among homeless individuals, while other people living in precarious conditions and employees were more likely to be European. There were only four pregnant women (between 26 and 36 weeks of pregnancy), all housed in Hotel 3. Regarding clinical findings, among all the participants, 22.1% reported at least one respiratory symptom or fever with significant variations among different populations. The highest prevalence was observed among employees (25.7%) and homeless persons (24.3%). A cough was the most commonly reported symptom (32.7%) followed by rhinorrhoea (20.4%), dyspnoea (12.2%) and fever (12.2%). No deaths were reported during the study period. In total, 49 participants (7.0%) tested positive for SARS-CoV-2, including 37 homeless people (of 441, 9.0%) and 12 employees (of 152, 7.9%, including seven security staff from Shelters A, B and C and residence γ , four nurses from Shelter A and one management staff member from Shelter C). Only two female homeless people tested positive, including one woman who was 36 weeks pregnant and who frequently attended the hospital during the lockdown and one person with mental illness who did not comply with lockdown measures. proportion of asymptomatic carriers among all tested individuals was 3.6% and that of symptomatic carriers was 3.4%. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.05.20091934 doi: medRxiv preprint Table 3 shows SARS-CoV-2 positivity rates among homeless people according to the time of screening, demographics and housing facility, using univariate analysis. No significant differences were observed according to gender and country of origin regarding SARS-CoV-2 positivity rates. Screening between C14 and C20 and screening in the group B population (Shelter B and hotels to which people from Shelter B were moved) resulted in a significantly higher proportion of positive PCR as compared to screening before C14 or screening in other homeless facilities, respectively. In addition, being young (18-34 years) was associated with an increased prevalence of virus detection. Cough, rhinorrhoea and fever were associated with viral carriage. Using multivariate analysis (Table 4) , being young and screening conducted in the group B population remained significantly associated with a higher likelihood of SARS-CoV-2 detection. To our knowledge, this is the only study addressing SARS-CoV-2 carriage among different precarious populations including homeless adults but also children and other hard-to-reach populations during the COVID-19 outbreak in France. The strength of our study is its large population size, with a high (78.9%) acceptance rate toward testing, particularly among individuals living in precarious conditions (92.1%) suggesting that this population is concerned about the disease. We found an overall 7.0% SARS-CoV-2 positivity rate, with most infected individuals among homeless people and employees working in homeless facilities, while no cases were found in asylum-seekers and in other people also living in precarious conditions. Detection of SARS-CoV-2 correlated with symptoms although many patients who tested positive did not report any respiratory symptoms or fever. Homeless people and professionals in contact with homeless people are therefore at a high risk of COVID-19. These populations should benefit from screening campaigns and specific measures aiming at mitigating the risks of transmission of the disease within these populations and to the overall population should be implemented. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . Table 3 . Characteristics of different populations studied Table 4 . Associations between multiple factors and SARS-CoV-2 positivity among 411 homeless people (univariate and multivariate analysis . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. . is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. Grey cells: four groups in study : Homeless people (N=411); other specific population living in precarious conditions (N=58), asylum seekers (N=77), and employees (N=152) and SARS-CoV-2 prevalence in each group. . It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. Bold lines indicate the variables recruited in initial multivariate mode. . It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 11, 2020. 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