The COVID-19 Infectious Disease Ontology (IDO-COVID-19) is an extension of the Infectious Disease Ontology (IDO) and the Virus Infectious Disease Ontology (VIDO). IDO Virus follows OBO Foundry guidelines, employs the Basic Formal Ontology as its starting point, and covers epidemiology, classification, pathogenesis, and treatment of terms used to represent infection by the SARS-CoV-2 virus strain, and the associated COVID-19 disease. Other terms are defined as cross-products of terms from Foundry ontologies to the extent possible.