Emerging in China in December 2019, Covid-19, whose pathogen is SARS-Cov-2, was declared a global pandemic in March 2020. The clinical presentation is highly variable, ranging from asymptomatic forms to acute respiratory distress and even death. Transmission is by droplet route, with an R0 of approximately 3.

Rapidly, population protection measures were put in place by governments, including the confinement of all persons whose functions were not considered essential and the closure of educational institutions.

Health care institutions are places at risk of Covid-19 transmission and hospital staff are particularly exposed, either through direct contact with patients, contact with exposed persons or through the environment. In order to protect personnel, hygiene measures were immediately recalled and reinforced.

During the period of containment, the majority of students from the Lyon-Bron Military Medical Schools were sent as reinforcement in Army Training Hospitals and in the Military Reanimation Unit (Mulhouse). Some students developed symptomatic forms of SARS-Cov-2 infection, documented by positive PCR, during Operation Resilience or on their return from the mission.

The Lyon-Bron Military Medical Schools staff, exposed both to the initial phase of the epidemic and to national protection measures, represent an extremely interesting population for understanding the epidemiological dynamics of the virus.

Inclusion Criteria:

• at least 18 years of age
• personnel of the Military Health Schools of Lyon-Bron
• working at the Military Health Schools of Lyon-Bron during the COVID-19 crisis

Exclusion Criteria:

• under 18
• contraindication to blood sampling

The study population will be composed of personnel of the Military Health Schools of Lyon-Bron (students, teachers, supervisors).