inclusion criteria: healthcare workers in service during the covid-19 outbreak including medical, nurse, technical, and auxiliary staff. negative rapid serologic and molecular testing for sars-cov-2. written informed consent.

inclusion criteria: healthcare workers in service during the covid-19 outbreak including medical, nurse, technical, and auxiliary staff. negative rapid serologic and molecular testing for sars-cov-2. written informed consent.

inclusion criteria: 1. healthcare workers in service during the covid-19 outbreak including medical, nurse, technical, and auxiliary staff. 2. negative rapid serologic and molecular testing for sars-cov-2. 3. written informed consent.

inclusion criteria: 1. healthcare workers in service during the covid-19 outbreak including medical, nurse, technical, and auxiliary staff. 2. negative rapid serologic and molecular testing for sars-cov-2. 3. written informed consent.