Since March 2020, France has been confronted with the SARS-COV-2 pandemic. Analysis of the data of its spread would indicate that close contact between individuals is necessary and containment would be the best way to contain this virus. France has therefore been contained since March 17, 2020 until 11 May 2020.

In order to assess the impact of the measures taken (containment) to protect patients and salaried staff of a french anti-cancer center on the spread of the virus, this observational study assesses the specific seroprevalence of SARS-COV-2 in all caregivers and non-carers of this hospital and in patients treated in consultation, day hospitalization, full hospitalization at the end of the containment period.

The objective for the staff cohort is to describe the seroprevalence and the link between the seroprevalence and sociological / demographic factors relating to the category of profession, to the contacts with the patients, to the presence in the hospital during the period of containment, to the conditions of home containment.

The objective for the patient cohort is to describe the seroprevalence and the link between the seroprevalence and factors relating to the type of cancer treated, the type of treatment and their possible modification during the period of containment, to the conditions of home containment.

Inclusion Criteria:

• Patient group:

Patient over 18 years old. Patient who gave his non-opposition to carrying out the study. Patient affiliated to the social security scheme.

• Salaried staff group:

Salaried staff over 18 years old. Salaried staff not opposing the carrying out of the study. Salaried staff affiliated to the social security scheme.

Exclusion Criteria:

• Patient group:

Minor patient, under legal protection or subject to a legal protection measure Patient deprived of liberty or under guardianship Inability to undergo medical monitoring of the trial for geographical, social or psychological reasons Patient refusal to participate Pregnant or nursing mothers

• Salaried staff group:

Underage salaried staff or under legal protection Salaried staff deprived of liberty or under guardianship Inability of the salaried staff to submit to the monitoring of the test: filling out the questionnaire and taking a blood sample Salaried staff refusal to participate in the study

Patients treated in the anti-cancer hospital of the study and all salaried staff of the anti-cancer hospital of the study.