Hospital staff, on the front line in the COVID-19 crisis, have many questions about the risk that they have been infected with this potentially fatal virus. These questions of course primarily concern caregivers working in sectors dedicated to COVID-19 patients, whether they are resuscitating or not, but also those in non-COVID-19 sectors, or even staff without direct contact with patients. In addition, depending on the suddenness and intensity of this "COVID-19 wave", these personnel have been more or less trained and sometimes exposed due to the dire lack of protective equipment. In some countries such as Great Britain, this has resulted in significant absenteeism, a source of deepening the shortage of caregivers.

This proportion of contaminated caregivers has not been evaluated on the whole of French territory. Studies from other countries suggest figures ranging from 1.5% in China to 20% in Italy. It is therefore impossible to rely on such variable data to have a reliable estimate.

Since june 2020, all staff in French health establishments could benefit a serological test.

Thus, in this epidemiological study, we propose to rely on this institutional serological screening to describe the link between seroconversion of hospital staff, regional intensity of the epidemic, and sectors of activity (COVID-19 sectors, non-COVID-19 caregivers , non-COVID-19 non-caregivers.

Inclusion Criteria:

• Hospital staff from Argenteuil, Belfort, Dijon and Limoges hospitals.
• Age ≥ 18 years old
• Participation agreement

Exclusion Criteria:

• Protected persons
• Refusal of participation

Hospital staff