The SARS-CoV2 virus is responsible for a variety of unknown, non-specific clinical symptoms ranging from asymptomatic to severe respiratory forms. This clinical polymorphism causes an underestimation of the number of proven cases (having symptoms consistent with a positive PCR) and of the incidence of the disease as a result.
The strategy to end the lockdown primarily relies on the existence of herd immunity to reduce the human-to-human transmission of the virus, thereby protecting uninfected individuals.
Herd immunity therefore cannot be assessed based on the number of proven cases.
Performing specific serologies for SARS-Cov2 in the general population seems to be a relevant method to evaluate the actual prevalence of the infection to plan how the lock-down is lifted.
The main objective of the study is to determine the percentage of patients presenting a seroconversion against SARS-Cov2 (significant presence of IgG or IgM) in the population of Hauts de France – patients going to the emergency department of the Lille CHU, patients consulting practitioners or surgeons as outpatients or needing a scheduled surgical procedure at the Lille CHU and finally, in collaboration with the URPS de Biologie (Regional union of health professionals), non-hospitalized patients who need to have blood tests in a biology laboratory for other reasons.