Inclusion Criteria:  Active workers from Centro Medico Bournigal (CMBO) and Centro Medico Punta Cana (CMPC) during the study.  Exclusion Criteria  Workers with positive Covid-19 RT-PCR prior to the start of the study Those that did not take the first dose of Ivermectin the first week at the start of the study Those that did not complied with at least 2 out of 4 weekly doses Those that had greater than 14 days difference in days between two intakes Ivermectin