WHO Digital Documentation of COVID-19 Certificates (DDCC)
1.0.0 - CI Build
WHO Digital Documentation of COVID-19 Certificates (DDCC)
1.0.0 - CI Build
WHO Digital Documentation of COVID-19 Certificates (DDCC), published by WHO. This guide is not an authorized publication; it is the continuous build for version 1.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/WorldHealthOrganization/ddcc/tree/main and changes regularly. See the Directory of published versions
| Draft as of 2025-03-10 |
Definitions for the DDCCCoreDataSet logical model.
Guidance on how to interpret the contents of this table can be found here
| 0. DDCCCoreDataSet | |
| Definition | Data elements for the DDCC Core Data Set. |
| Short | DDCC Core Data Set Logical Model |
| Control | 0..* |
| Is Modifier | false |
| Logical Model | Instances of this logical model are not marked to be the target of a Reference |
| 2. DDCCCoreDataSet.name | |
| Definition | The full name of the person. |
| Short | Name |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 4. DDCCCoreDataSet.birthDate | |
| Definition | The person's date of birth (DOB) if known. If unknown, use given DOB for administrative purposes |
| Short | Date of birth |
| Control | 0..1 |
| Type | date |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 6. DDCCCoreDataSet.identifier | |
| Definition | Unique identifier for the person, according to the policies applicable to each country. There can be more than one unique identifier used to link records. (e.g. national ID, health ID, immunization information system ID, medical record ID). |
| Short | Unique identifier |
| Note | This is a business identifier, not a resource identifier (see discussion) |
| Control | 0..1 |
| Type | Identifier |
| Summary | true |
| 8. DDCCCoreDataSet.certificate | |
| Definition | Metadata associated with the certificate |
| Short | Certificate Metadata |
| Control | 0..1 |
| Type | BackboneElement |
| Summary | true |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |
| 10. DDCCCoreDataSet.certificate.id | |
| Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| Short | Unique id for inter-element referencing |
| Control | 0..1 |
| Type | string |
| Is Modifier | false |
| XML Format | In the XML format, this property is represented as an attribute. |
| Summary | false |
| 12. DDCCCoreDataSet.certificate.extension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. |
| Short | Additional content defined by implementations |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | false |
| Summary | false |
| Alternate Names | extensions, user content |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists()) |
| Slicing | This element introduces a set of slices on DDCCCoreDataSet.certificate.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators: |
| 14. DDCCCoreDataSet.certificate.modifierExtension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself). |
| Short | Extensions that cannot be ignored even if unrecognized |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them |
| Summary | true |
| Requirements | Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions. |
| Alternate Names | extensions, user content, modifiers |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists()) |
| 16. DDCCCoreDataSet.certificate.issuer | |
| Definition | Certificate issuer. |
| Short | Certificate issuer |
| Control | 1..1 |
| Type | Reference(DDCC Organization) |
| Summary | true |
| 18. DDCCCoreDataSet.certificate.kid | |
| Definition | Key ID |
| Short | Key ID used to verify the signature of the certificate |
| Control | 0..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 20. DDCCCoreDataSet.certificate.hcid | |
| Definition | Health certificate identifier (HCID). |
| Short | Health certificate identifier (HCID) |
| Control | 1..1 |
| Type | Identifier |
| Summary | true |
| 22. DDCCCoreDataSet.certificate.ddccid | |
| Definition | DDCC Identifier |
| Short | DDCC Identifier |
| Control | 0..1 |
| Type | Identifier |
| Summary | true |
| 24. DDCCCoreDataSet.certificate.version | |
| Definition | Certificate schema version |
| Short | Certificate schema version |
| Note | This is a business version Id, not a resource version Id (see discussion) |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 26. DDCCCoreDataSet.certificate.period | |
| Definition | Certificate validity period. |
| Short | Certificate Validity Period |
| Control | 0..1 |
| Type | Period |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))per-1: If present, start SHALL have a lower value than end ( start.hasValue().not() or end.hasValue().not() or (start <= end)) |
| 28. DDCCCoreDataSet.certificate.period.id | |
| Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| Short | Unique id for inter-element referencing |
| Control | 0..1 |
| Type | string |
| Is Modifier | false |
| XML Format | In the XML format, this property is represented as an attribute. |
| Summary | false |
| 30. DDCCCoreDataSet.certificate.period.extension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. |
| Short | Additional content defined by implementations |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | false |
| Summary | false |
| Alternate Names | extensions, user content |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists()) |
| Slicing | This element introduces a set of slices on DDCCCoreDataSet.certificate.period.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators: |
| 32. DDCCCoreDataSet.certificate.period.start | |
| Definition | Start date of certificate validity. The start of the period. The boundary is inclusive. |
| Short | Certificate valid fromStarting time with inclusive boundary |
| Comments | If the low element is missing, the meaning is that the low boundary is not known. |
| Control | 0..1 This element is affected by the following invariants: per-1 |
| Type | dateTime |
| Is Modifier | false |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |
| 34. DDCCCoreDataSet.certificate.period.end | |
| Definition | End date of certificate validity. The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time. |
| Short | Certificate valid untilEnd time with inclusive boundary, if not ongoing |
| Comments | The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03. |
| Control | 0..1 This element is affected by the following invariants: per-1 |
| Type | dateTime |
| Is Modifier | false |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| Meaning if Missing | If the end of the period is missing, it means that the period is ongoing |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |
Guidance on how to interpret the contents of this table can be found here
| 0. DDCCCoreDataSet | |
| Definition | Data elements for the DDCC Core Data Set. |
| Short | DDCC Core Data Set Logical Model |
| Logical Model | Instances of this logical model are not marked to be the target of a Reference |
| 2. DDCCCoreDataSet.name | |
| Definition | The full name of the person. |
| Short | Name |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 4. DDCCCoreDataSet.birthDate | |
| Definition | The person's date of birth (DOB) if known. If unknown, use given DOB for administrative purposes |
| Short | Date of birth |
| Control | 0..1 |
| Type | date |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 6. DDCCCoreDataSet.identifier | |
| Definition | Unique identifier for the person, according to the policies applicable to each country. There can be more than one unique identifier used to link records. (e.g. national ID, health ID, immunization information system ID, medical record ID). |
| Short | Unique identifier |
| Note | This is a business identifier, not a resource identifier (see discussion) |
| Control | 0..1 |
| Type | Identifier |
| 8. DDCCCoreDataSet.certificate | |
| Definition | Metadata associated with the certificate |
| Short | Certificate Metadata |
| Control | 0..1 |
| Type | BackboneElement |
| 10. DDCCCoreDataSet.certificate.issuer | |
| Definition | Certificate issuer. |
| Short | Certificate issuer |
| Control | 1..1 |
| Type | Reference(DDCC Organization) |
| 12. DDCCCoreDataSet.certificate.kid | |
| Definition | Key ID |
| Short | Key ID used to verify the signature of the certificate |
| Control | 0..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 14. DDCCCoreDataSet.certificate.hcid | |
| Definition | Health certificate identifier (HCID). |
| Short | Health certificate identifier (HCID) |
| Control | 1..1 |
| Type | Identifier |
| 16. DDCCCoreDataSet.certificate.ddccid | |
| Definition | DDCC Identifier |
| Short | DDCC Identifier |
| Control | 0..1 |
| Type | Identifier |
| 18. DDCCCoreDataSet.certificate.version | |
| Definition | Certificate schema version |
| Short | Certificate schema version |
| Note | This is a business version Id, not a resource version Id (see discussion) |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 20. DDCCCoreDataSet.certificate.period | |
| Definition | Certificate validity period. |
| Short | Certificate Validity Period |
| Control | 0..1 |
| Type | Period |
| 22. DDCCCoreDataSet.certificate.period.start | |
| Definition | Start date of certificate validity. |
| Short | Certificate valid from |
| Control | 0..1 |
| Type | dateTime |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 24. DDCCCoreDataSet.certificate.period.end | |
| Definition | End date of certificate validity. |
| Short | Certificate valid until |
| Control | 0..1 |
| Type | dateTime |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
Guidance on how to interpret the contents of this table can be found here
| 0. DDCCCoreDataSet | |
| Definition | Data elements for the DDCC Core Data Set. |
| Short | DDCC Core Data Set Logical Model |
| Control | 0..* |
| Is Modifier | false |
| Logical Model | Instances of this logical model are not marked to be the target of a Reference |
| 2. DDCCCoreDataSet.name | |
| Definition | The full name of the person. |
| Short | Name |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 4. DDCCCoreDataSet.birthDate | |
| Definition | The person's date of birth (DOB) if known. If unknown, use given DOB for administrative purposes |
| Short | Date of birth |
| Control | 0..1 |
| Type | date |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 6. DDCCCoreDataSet.identifier | |
| Definition | Unique identifier for the person, according to the policies applicable to each country. There can be more than one unique identifier used to link records. (e.g. national ID, health ID, immunization information system ID, medical record ID). |
| Short | Unique identifier |
| Note | This is a business identifier, not a resource identifier (see discussion) |
| Control | 0..1 |
| Type | Identifier |
| Summary | true |
| 8. DDCCCoreDataSet.certificate | |
| Definition | Metadata associated with the certificate |
| Short | Certificate Metadata |
| Control | 0..1 |
| Type | BackboneElement |
| Summary | true |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |
| 10. DDCCCoreDataSet.certificate.id | |
| Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| Short | Unique id for inter-element referencing |
| Control | 0..1 |
| Type | string |
| Is Modifier | false |
| XML Format | In the XML format, this property is represented as an attribute. |
| Summary | false |
| 12. DDCCCoreDataSet.certificate.extension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. |
| Short | Additional content defined by implementations |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | false |
| Summary | false |
| Alternate Names | extensions, user content |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))ext-1: Must have either extensions or value[x], not both ( extension.exists() != value.exists()) |
| Slicing | This element introduces a set of slices on DDCCCoreDataSet.certificate.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators: |
| 14. DDCCCoreDataSet.certificate.modifierExtension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself). |
| Short | Extensions that cannot be ignored even if unrecognized |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them |
| Summary | true |
| Requirements | Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions. |
| Alternate Names | extensions, user content, modifiers |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))ext-1: Must have either extensions or value[x], not both ( extension.exists() != value.exists()) |
| 16. DDCCCoreDataSet.certificate.issuer | |
| Definition | Certificate issuer. |
| Short | Certificate issuer |
| Control | 1..1 |
| Type | Reference(DDCC Organization) |
| Summary | true |
| 18. DDCCCoreDataSet.certificate.kid | |
| Definition | Key ID |
| Short | Key ID used to verify the signature of the certificate |
| Control | 0..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| 20. DDCCCoreDataSet.certificate.hcid | |
| Definition | Health certificate identifier (HCID). |
| Short | Health certificate identifier (HCID) |
| Control | 1..1 |
| Type | Identifier |
| Summary | true |
| 22. DDCCCoreDataSet.certificate.ddccid | |
| Definition | DDCC Identifier |
| Short | DDCC Identifier |
| Control | 0..1 |
| Type | Identifier |
| Summary | true |
| 24. DDCCCoreDataSet.certificate.version | |
| Definition | Certificate schema version |
| Short | Certificate schema version |
| Note | This is a business version Id, not a resource version Id (see discussion) |
| Control | 1..1 |
| Type | string |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| 26. DDCCCoreDataSet.certificate.period | |
| Definition | Certificate validity period. |
| Short | Certificate Validity Period |
| Control | 0..1 |
| Type | Period |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))per-1: If present, start SHALL have a lower value than end ( start.hasValue().not() or end.hasValue().not() or (start <= end)) |
| 28. DDCCCoreDataSet.certificate.period.id | |
| Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| Short | Unique id for inter-element referencing |
| Control | 0..1 |
| Type | string |
| Is Modifier | false |
| XML Format | In the XML format, this property is represented as an attribute. |
| Summary | false |
| 30. DDCCCoreDataSet.certificate.period.extension | |
| Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. |
| Short | Additional content defined by implementations |
| Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| Control | 0..* |
| Type | Extension |
| Is Modifier | false |
| Summary | false |
| Alternate Names | extensions, user content |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))ext-1: Must have either extensions or value[x], not both ( extension.exists() != value.exists()) |
| Slicing | This element introduces a set of slices on DDCCCoreDataSet.certificate.period.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators: |
| 32. DDCCCoreDataSet.certificate.period.start | |
| Definition | Start date of certificate validity. |
| Short | Certificate valid from |
| Comments | If the low element is missing, the meaning is that the low boundary is not known. |
| Control | 0..1 This element is affected by the following invariants: per-1 |
| Type | dateTime |
| Is Modifier | false |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |
| 34. DDCCCoreDataSet.certificate.period.end | |
| Definition | End date of certificate validity. |
| Short | Certificate valid until |
| Comments | The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03. |
| Control | 0..1 This element is affected by the following invariants: per-1 |
| Type | dateTime |
| Is Modifier | false |
| Primitive Value | This primitive element may be present, or absent, or replaced by an extension |
| Summary | true |
| Meaning if Missing | If the end of the period is missing, it means that the period is ongoing |
| Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) |