PMC:7160442 / 6601-6779 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T40","span":{"begin":0,"end":178},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Serological studies have been started in several European countries to define population immunity and studies on the duration of immunity will need to be conducted in the future."}