A new study preprinted June 13 on medRxiv looks at the characteristics of COVID patients who have tested positive for the virus more than once. Researchers pulled clinical and testing data for 23 patients from a large U.S. electronic health record database. The patients had positive test results at least 60 days apart and separated by at least two consecutive negative test results—making it clear that these were reinfection cases, not cases in which people had prolonged COVID infections. According to the study, 96 percent of these reinfected patients had two or more comorbidities, which is the simultaneous presence of diseases or medical conditions within a patient. In this study, 70 percent of the patients had hypertension, 26 percent had cardiovascular disease, atrial fibrillation, or chronic kidney disease, and 22 percent had type 2 diabetes or a history of venous thromboembolism or long-term anticoagulation. These are all considered risk factors for COVID by the Centers for Disease Control and Prevention (CDC).