To date, in France, in the context of the SARS Cov2 pandemic,both the number of affected subjects and the number of severe forms requiring hospital care are increasing.

Several nosocomial transmission clusters have already been identified in hospitals (both pediatric and adult) but there is still limited data on the nosocomial spread of SARS-Cov2.

This nosocomial transmission affects both patients and caregivers. It is important to understand the spread of the virus within the hospital. This will help to optimize procedures to prevent transmission to caregivers and hospitalizedpatients not infected with SARS Cov2, and more generally this will contribute to control the spread of SARS Cov2 in the community

It is an observational study without any risk. Every participating service will be investigated for 2 consecutive days .

• At each staff rotation, an individualsensorwill be provided toall thestaff(caregivers, administrative, students etc…) to be worn duringtheirworking hours. Also a sensor will be placed at each patient's bedside.
• In addition, epidemiological data relating to socio-demographic characteristics, profession, protective measures will be collectedfrom hospitalstaff. Also, some data from the 'entrepot des données de santé" regarding individual carepathways in the hospitalwill be extracted.
• A map of the unit, specifying the location of each patient will be made.

Inclusion Criteria for patients:

• Informed of the purpose of the study and having expressed his non-opposition or of a relative (if the patient's state of health does not allow it)
• Hospitalized in one of the participating departments

Inclusion criteria for hospital staff:

• Informed of the objective of the study and having expressed his no opposition
• Having daily contact with patients hospitalized in participating departments

Inclusion criteria for patient visitors

• Informed of the purpose of the study and having expressed his non-opposition
• Having daily contacts with patients hospitalized in the participating departments

Exclusion Criteria for evryone (patient, hospital staff and patients visitors) :

• Refuse to participate

Working caregivers and hospitalized patients in care services dedicated or not to SARS Cov2 (including resuscitation services) in both adult and pediatric hospitals. Investigator will be interested in both adult and child services because the latter present a pauci-symptomatic form so the dynamics of transmission can be different.