Query: When was the last time I received the influenza vaccine?, FHIR Resource: {'resourceType': 'Observation', 'status': 'final', 'category': [{'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/observation-category', 'code': 'vital-signs', 'display': 'Vital signs'}]}], 'code': {'coding': [{'system': 'http://loinc.org', 'code': '8302-2', 'display': 'Body Height'}], 'text': 'Body Height'}, 'subject': {'reference': 'urn:uuid:ad40c953-7b35-9094-13ec-0e7818dcc10b'}, 'effectiveDateTime': '2015-12-25T19:12:34+05:30', 'valueQuantity': {'value': 175.2, 'unit': 'cm', 'system': 'http://unitsofmeasure.org', 'code': 'cm'}, 'interpretation': None}