The recent SARS-CoV2 pandemic has highlighted that the transmission of the virus within health care facilities plays a fundamental role in its propagation and, therefore, in the increase in COVID-19 cases registered among patients and healthcare workers.

This study, original for the current lack of data on nosocomial transmission mechanisms compared to what happens in the community, proposes to conduct a study in patients, health workers and people in real-life setting.

The study will be monocentric and performed at the San Raffaele Pisana Institute in Rome, that is able to guarantee the necessary number and the right case-mix that will allow to evaluate any possible correlations between infection and pre-existing disease.

Furthermore, hospitals, especially those dedicated to chronic patients, as well as other communities that are not completely closed (such as school and work communities), are also at greater risk of small outbreaks that also affect healthcare professionals.

It is therefore necessary to carry out periodic checks on all healthcare professionals who work in healthcare facilities both to ensure their health and avoid the risk of possible contamination and to prevent the possible transmission of infection from the community to the hospital.

Another essential aspect to prevent infection in such facilities is the control of colonization in admitted patients.

Negativity from SARS-CoV2 should be carefully monitored in these patients prior to their placement in different departments.

On this basis, the study aims to determine the presence of SARS-CoV2 by monitoring with serial nasopharyngeal swabs carried out on healthcare professionals working within the facility and on new patients admitted.

In order to exclude the possibility of false negatives due to low viral load found in the early stages of infection (incubation time) or any exposure that may occur in the days following the execution of the swab, the study will i provide for the repetition of the swab examination, 3 times, at weekly intervals.

In order to verify the correspondence between the presence of IgM and IgG antibodies against the virus and the positivity to the swabs, the healthcare professionals and patients who undergoing nasopharyngeal swab will be previously subjected to the rapid antibody detection test (prick test for IgG and IgM).

Inclusion Criteria:

• Patients/Participants > 18 years
• Subjects who agree with the study signing the informed consent

Exclusion Criteria:

• Age <18 years;
• Pregnancy in progress;
• Simultaneous participation in another clinical study
• Ongoing immunosuppressive therapy or during the last month

Study will be on healthcare workers in direct contact with patients (pts). Surveillance will be done on new admitted pts to evaluate prevalence of infection among pts in pulmonary, or cardiac rehabilitation.

Data will allow to reconstruct eventual transmission and compare values observed in healthcare and real life. Random samples will be done in subjects from the population without obvious risk factors.

Study will have 3 groups:

• 200-300 healthcare workers in direct patients contact, incl. staff at registration desk. 100-200 pts admitted to rehabilitation at the Institute, referred from other health facilities will be enrolled in the study.
• 100 volunteers in Real-life will be other employees, staff not in contact with patients