text: Evolving Phenotypes of non hospitalized Patients that Indicate Long Covid For some SARS CoV 2 survivors recovery from the acute phase of the infection has been grueling with lingering effects Many of the symptoms characterized as the post acute sequelae of COVID 19 PASC could have multiple causes or are similarly seen in non COVID patients Accurate identification of phenotypes will be important to guide future research and help the healthcare system focus its efforts and resources on adequately controlled age and gender specific sequelae of a COVID 19 infection In this retrospective electronic health records EHR cohort study we applied a computational framework for knowledge discovery from clinical data MLHO to identify phenotypes that positively associate with a past positive reverse transcription polymerase chain reaction RT PCR test for COVID 19 We evaluated the post test phenotypes in two temporal windows at 3 6 and 6 9 months after the test and by age and gender Data from longitudinal diagnosis records stored in EHRs from Mass General Brigham in the Boston metropolitan area was used for the analyses Statistical analyses were performed on data from March 2020 to June 2021 Study participants included over 96 thousand patients who had tested positive or negative for COVID 19 and were not hospitalized We identified 33 phenotypes among different age gender cohorts or time windows that were positively associated with past SARS CoV 2 infection All identified phenotypes were newly recorded in patientsâ medical records two months or longer after a COVID 19 RT PCR test in non hospitalized patients regardless of the test result Among these phenotypes a new diagnosis record for anosmia and dysgeusia OR 2 60 95 CI 1 94 3 46 alopecia OR 3 09 95 CI 2 53 3 76 chest pain OR 1 27 95 CI 1 09 1 48 chronic fatigue syndrome OR 2 60 95 CI 1 22 2 10 shortness of breath OR 1 41 95 CI 1 22 1 64 pneumonia OR 1 66 95 CI 1 28 2 16 and type 2 diabetes mellitus OR 1 41 95 CI 1 22 1 64 are some of the most significant indicators of a past COVID 19 infection Additionally more new phenotypes were found with increased confidence among the cohorts who were younger than 65 Our approach avoids a flood of false positive discoveries while offering a more robust probabilistic approach compared to the standard linear phenome wide association study PheWAS The findings of this study confirm many of the post COVID symptoms and suggest that a variety of new diagnoses including new diabetes mellitus and neurological disorder diagnoses are more common among those with a history of COVID 19 than those without the infection Additionally more than 63 percent of PASC phenotypes were observed in patients under 65 years of age pointing out the importance of vaccination to minimize the risk of debilitating post acute sequelae of COVID 19 among younger adults 