e13604 Background: To limit SARS-Co-2 transmission in general population, French government had set up a first National containment from March 16, 2020 to June 2, 2020. Furthermore, General Direction of our hospital have implemented and organized physical distancing (telework, teleconsultation, virtual multi-disciplinary board), mask wearing, use of alcoholic ... to limit interpersonal contacts. To assess the impact of this policy, we have carried out a seroprevalence study and identified risk factors for SARS-Co-2 prevalence among HCP in May/June 2020. Methods: This is part of CORSER Study (“Etude séro-épidémiologique du virus SARS-CoV-2 en France d’une Cohorte CORSER-2d de personnels d’établissements de santé »), registered with ClinicalTrials.gov (NCT04325646). Two serological tests were applied in this cohort: S-Flow assay and Luciferase-linked immune-sorbent assay (LuLisa-N test). Results: Between 04 May to 26 June 2020, 392 Osar Lambret Cancer Center employees were included in the present study (about 40% of all staff). The most common jobs were: 92 nurses (23.4%), 80 radiology/radiotherapy manipulators (20.4%), 51 physicians (13.0%), 33 medical interns (8.4%) and 47 administrative staff members (11.9%). There were 98 men (25.0%) and 294 women (75.0%). The mean age was 38.7 (+/- 11.4). There were 7 seropositive cases; the seroprevalence was 1.8% (95%-CI: 0.7-3.6). Among the 7 positive cases, 5 were symptomatic (71.4%). In univariate analysis, factors associated with SARS-Co-2 seroprevalence: symptoms suggesting viral infection within 2 months (OR=5.33), dysgueusia (OR=37.00), anosmia (OR=66.29) and HCP exposed to COVID-19 patient outside work (OR=6.69). Gender, tobacco consumption, O blood group, HCP versus administrative staff, HCP working in different services, HCP providing care to suspected COVID-19 patients, HCP providing high-risk cares were not found to be associated with seropositivity. Of note, we have noticed that BMI≥ 24 kg/m² was associated with seroprevalence (OR=15.45), without biological rational. Conclusions: Our study suggests that strict implementation of protective measures was associated with low SARS-Cov-2 prevalence at the end of first National Containment, including among HCP treating COVID-19+ patients. HCPs seroprevalence seemed lower than seroprevalence of the general population at the same period (4-5%). Clinical trial information: NCT04325646.
