Prévalence du SARS-CoV-2, étude sérologique en France chez des salariés non confinés et confinés

OBJECTIVES: Retrospectively assess the rate of employees, confined (teleworking) and not confined, infected with SARS-CoV-2 from the end of April 2020 to July 2020, after the 1st lockdown (April to May 2020). METHOD: A serological test for anti-SARS-CoV-2 antibodies, IgG and IgM, with a questionnaire on the symptoms was proposed to 2100 employees of the same company. RESULTS: Among the 786 included employees, serology was positive for: 4.05% in the unconfined, and 6.72%, in the confined (P = NS). Symptoms were present for 86.4% of positives, with no significant difference between confined and non-confined. Among asymptomatic, 1.7% were positives. No symptoms were significantly different between the 2 groups apart from anosmia-ageusia significantly more often observed in the confined group. Symptoms significantly associated with positive serology were anosmia-ageusia, fever-fever sensation -chill, body aches, fatigue and/or malaise, influenza-like illness and respiratory symptoms. This low rate of contamination may be the result of reinforced prevention measures put in place for employees from the end of January 2020, and the regular information meetings with the Occupational Health Doctor about prevention of the risk of contamination in the company. CONCLUSIONS: The rate of employees who were infected with SARS-CoV-2 from the end of April 2020 to July 2020 was half the rate reported in the population of Ile de France at the same period, without difference between employees who continued their activity face-to-face compared to those who had been in confinement.