The medical and paramedical staff of the front-line services are potentially exposed to SARS-CoV-2. Therefore, despite the application of standard protective measures, it is possible that a certain number of these personnel have already contracted SARS-CoV-2, including in its asymptomatic form. Serological testing in this context would be useful for deploying immune healthcare workers as to limit the risk of viral infection and transmission. Therefore, it is of utmost importance to prove that the serological response entails the production of neutralizing antibodies.

Inclusion Criteria:

• Not previously diagnosed with COVID-19 except for convalescents
• Not currently symptomatic with fever or respiratory symptoms (cough, dyspnea)

Exclusion Criteria:

• Patients with fever or respiratory symptoms (cough, dyspnea)
• Refusal to give informed consent, or contraindication to venipuncture.

Age-stratified sample from general population with 3 subgroups:

1. Healthcare workers (HCWs), comprising frontline doctors, nurses, health attendants, and receptionists.
2. Healthy blood donors and healthy subjects in blood bank or laboratory (routine examinations as pre-employment, likely to be representative of the general population
3. Convalescents