PMC:7784824 / 1850-1960 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T27","span":{"begin":41,"end":51},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":" 2nd week after symptom onset or later.\n\nBackground\nIn December 2019, several cases of an unidentified pneumon"}