D. Natividad III Graciano, Pastrana Edmart, PiƱera Rizalyn, Validity of PIRO Score as an Assessment Tool for Mortality Risk of COVID-19 Pneumonia among Patients Admitted to World Citi Medical Center from March to August 2020. A Retrospective Observational Cohort Study, International Journal of Coronaviruses, Volume 3, Issue 4, 2021, Pages 1-9, ISSN 2692-1537, https://doi.org/10.14302/issn.2692-1537.ijcv-21-4045. (https://openaccesspub.orgijcv/article/1747) Keywords: COVID-19; PIRO; Pneumonia