Inclusion Criteria:  Men and women health workers in the General Tijuana Hospital, Mexico who works in high-risk areas with direct contact with patients infected and diagnosed with COVID-19.  Exclusion Criteria:  persons with history of hypersensitivity to silver (rashes and other contraindications), a history of SARS-CoV-2 infection in the three months prior to the start of the study, any respiratory distress, and refusal to sign the informed consent.