The main purpose is to study the prevalence of Covid-19 in EHPAD. The primary endpoint will be the combination of PCR results and symptomatology, making it possible to define positive cases in EHPAD, in residents and professionals in contact with them. The prevalence obtained can be compared with the results of serology if these are performed.

This study is taking place in several nursing homes in Ile-de-France, which will be recruited at the end of the diagnostic campaign.

At the initiative of the ARS Ile-de-France, residents and professionals of selected EHPADs will be subjected to systematic screening by RT-PCR for Covid-19, then by serology after the first screening, regardless of whether either the result

Samples, by nasopharyngeal swab for RT-PCR, by capillary blood sampling or venipuncture according to the technique for serology, will be carried out according to the doctrines issued by the ARS Ile de France and the variations proposed by the appropriate departmental directorates in depending on local resources. The results will be brought to the attention of EHPADs to adapt the care of residents and positive professionals.

Data will be collected daily from collection for the first test (RT-PCR), or retrospectively if the collection took place before the study.

Regarding the approach for collecting serologies:

• All subjects included with a negative PCR will be offered the serological test, in accordance with the recommendations in force or the medical decisions of the establishments.
• The qualitative results of the serologies of the subjects included in the study (residents and professionals) will be collected according to the same circuit as those of the RT-PCRs.
• Only the symptoms of residents with a positive serology will be collected, from the date of the sample and for a period of 14 days.
• The symptoms of professionals with a positive serology can be collected, from the date of the sample and for a period of 14 days without mandatory character.
• Both techniques (ELISA or TROD) are accepted and the serology values will not be collected.

Inclusion Criteria:

1. / Residents of nursing homes in Île-de-France in which systematic Covid-19 screening tests were carried out and agreeing to participate in the study.
2. / Professionals in nursing homes in Île-de-France in which systematic screening tests for Covid-19 were carried out and agreeing to participate in the study: nursing assistants, nurses, coordinating doctors, hotel and service agents hygiene, etc.

Exclusion Criteria:

1. / Expression of opposition to the collection of symptoms by professionals, residents or their legal representatives.
2. / Subjects who have not had a diagnostic test by RT-PCR.

Two types of population, EHPAD residents identified and EHPAD professionals