Seroprevalence and Immunoprotection Against SARS-CoV2 in Children Hospitalized in Paris

Background of the study:

The fraction of undiagnosed cases is a critical epidemiological characteristic that modulates the epidemic potential of SARS-CoV-2 emerging respiratory virus. These subjects most often present themselves in benign or totally asymptomatic form, although they are likely to spread the virus in the general population. The containment strategy was implemented in France to reverse the exponential epidemic growth of infection.

A crucial issue is the specific study of the paediatric population because the prevalence of symptomatic infections is low and children are mostly mild and under-diagnosed. Children could frequently be asymptomatic carriers and act as a real reservoir for the spread of the virus. In these "sub-symptomatic" carriers, the viral load may be low, and it is possible that PCR nasal tests may be defective. The serological study is therefore essential because it will inform us about the speed and effectiveness of seroconversion and therefore about the immunoprotection of this subpopulation.

The rationale for the study is that the proportion of children who have developed immunoprotection is decisive in defining measures to control the epidemic. It is essential to assess the prevalence and typology of antibody responses in this population and to follow kinetics over time.

The many emerging atypical forms and in particular the post-infectious kawasaki-like forms have a very particular immunopathological profile that provides information on the natural history of the disease.