Before revision:  The extracted information is also mapped to standard clinical concepts in the  common data model  of OHDSI OMOP.
After revision:  The extracted information is also mapped to standard clinical concepts in the common data model . A hybrid approach of combining deep learning-based models, curated lexicons, and pattern-based rules was applied to quickly build the COVID-19 SignSym from CLAMP, with optimized performance. Our extensive evaluation using 3 external sites with clinical notes of OHDSI OMOP.