Query: When was my last Hepatitis A immunization?, 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': '8289-1', 'display': 'Head Occipital-frontal circumference Percentile'}], 'text': 'Head Occipital-frontal circumference Percentile'}, 'subject': {'reference': 'urn:uuid:c3c262d7-4fa7-a191-7763-336a5562f55c'}, 'effectiveDateTime': '2021-12-16T02:23:54+05:30', 'valueQuantity': {'value': 87.98, 'unit': '%', 'system': 'http://unitsofmeasure.org', 'code': '%'}, 'interpretation': None}