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': 'laboratory', 'display': 'Laboratory'}]}], 'code': {'coding': [{'system': 'http://loinc.org', 'code': '18262-6', 'display': 'Low Density Lipoprotein Cholesterol'}], 'text': 'Low Density Lipoprotein Cholesterol'}, 'subject': {'reference': 'urn:uuid:ad40c953-7b35-9094-13ec-0e7818dcc10b'}, 'effectiveDateTime': '2016-01-22T19:12:34+05:30', 'valueQuantity': {'value': 132.42, 'unit': 'mg/dL', 'system': 'http://unitsofmeasure.org', 'code': 'mg/dL'}, 'interpretation': None}