inclusion criteria: * age 18 years or older * negative rt-pcr test at the beginning of the study. * negative sars-cov-2 serological elecsys anti-sars-cov-2 test at the beginning of the study. * living in a geographic area with active covid-19 transmission (number of * cases reported locally). * living in a geographic area that has been determined by the colombian national statistics department (dane) to have a medium, medium-high, and high vulnerability index (higher prevalence of comorbidities and social and economic vulnerabilities. * working outside the home for at least two days a week, during the last week. * acceptance to participate in the study regardless of the trial arm assignment through verbal informed consent.

inclusion criteria: * age 18 years or older * negative rt-pcr test at the beginning of the study. * negative sars-cov-2 serological elecsys anti-sars-cov-2 test at the beginning of the study. * living in a geographic area with active covid-19 transmission (number of * cases reported locally). * living in a geographic area that has been determined by the colombian national statistics department (dane) to have a medium, medium-high, and high vulnerability index (higher prevalence of comorbidities and social and economic vulnerabilities. * working outside the home for at least two days a week, during the last week. * acceptance to participate in the study regardless of the trial arm assignment through verbal informed consent.

inclusion criteria: - age 18 years or older - negative rt-pcr test at the beginning of the study. - negative sars-cov-2 serological elecsys anti-sars-cov-2 test at the beginning of the study. - living in a geographic area with active covid-19 transmission (number of - cases reported locally). - living in a geographic area that has been determined by the colombian national statistics department (dane) to have a medium, medium-high, and high vulnerability index (higher prevalence of comorbidities and social and economic vulnerabilities. - working outside the home for at least two days a week, during the last week. - acceptance to participate in the study regardless of the trial arm assignment through verbal informed consent.

inclusion criteria: - age 18 years or older - negative rt-pcr test at the beginning of the study. - negative sars-cov-2 serological elecsys anti-sars-cov-2 test at the beginning of the study. - living in a geographic area with active covid-19 transmission (number of - cases reported locally). - living in a geographic area that has been determined by the colombian national statistics department (dane) to have a medium, medium-high, and high vulnerability index (higher prevalence of comorbidities and social and economic vulnerabilities. - working outside the home for at least two days a week, during the last week. - acceptance to participate in the study regardless of the trial arm assignment through verbal informed consent.