WHO Digital Documentation of COVID-19 Certificates (DDCC)
1.0.0 - CI Build International flag

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/ and changes regularly. See the Directory of published versions

Logical Model: DDCCCoreDataSet - Detailed Descriptions

Draft as of 2024-10-17

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.

ShortDDCC Core Data Set Logical Model
Logical ModelInstances of this logical model are not marked to be the target of a Reference
2. DDCCCoreDataSet.name
Definition

The full name of the person.

ShortName
Control1..1
Typestring
Primitive ValueThis 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

ShortDate of birth
Control0..1
Typedate
Primitive ValueThis 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).

ShortUnique identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
8. DDCCCoreDataSet.certificate
Definition

Metadata associated with the certificate

ShortCertificate Metadata
Control0..1
TypeBackboneElement
10. DDCCCoreDataSet.certificate.issuer
Definition

Certificate issuer.

ShortCertificate issuer
Control1..1
TypeReference(DDCC Organization)
12. DDCCCoreDataSet.certificate.kid
Definition

Key ID

ShortKey ID used to verify the signature of the certificate
Control0..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
14. DDCCCoreDataSet.certificate.hcid
Definition

Health certificate identifier (HCID).

ShortHealth certificate identifier (HCID)
Control1..1
TypeIdentifier
16. DDCCCoreDataSet.certificate.ddccid
Definition

DDCC Identifier

ShortDDCC Identifier
Control0..1
TypeIdentifier
18. DDCCCoreDataSet.certificate.version
Definition

Certificate schema version

ShortCertificate schema version
NoteThis is a business version Id, not a resource version Id (see discussion)
Control1..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
20. DDCCCoreDataSet.certificate.period
Definition

Certificate validity period.

ShortCertificate Validity Period
Control0..1
TypePeriod
22. DDCCCoreDataSet.certificate.period.start
Definition

Start date of certificate validity.

ShortCertificate valid from
Control0..1
TypedateTime
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
24. DDCCCoreDataSet.certificate.period.end
Definition

End date of certificate validity.

ShortCertificate valid until
Control0..1
TypedateTime
Primitive ValueThis 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.

ShortDDCC Core Data Set Logical Model
Control0..*
Is Modifierfalse
Logical ModelInstances of this logical model are not marked to be the target of a Reference
2. DDCCCoreDataSet.name
Definition

The full name of the person.

ShortName
Control1..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
4. DDCCCoreDataSet.birthDate
Definition

The person's date of birth (DOB) if known. If unknown, use given DOB for administrative purposes

ShortDate of birth
Control0..1
Typedate
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
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).

ShortUnique identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
Summarytrue
8. DDCCCoreDataSet.certificate
Definition

Metadata associated with the certificate

ShortCertificate Metadata
Control0..1
TypeBackboneElement
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. 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).

ShortExtensions 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.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
Summarytrue
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 Namesextensions, user content, modifiers
Invariantsele-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())
12. DDCCCoreDataSet.certificate.issuer
Definition

Certificate issuer.

ShortCertificate issuer
Control1..1
TypeReference(DDCC Organization)
Summarytrue
14. DDCCCoreDataSet.certificate.kid
Definition

Key ID

ShortKey ID used to verify the signature of the certificate
Control0..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
16. DDCCCoreDataSet.certificate.hcid
Definition

Health certificate identifier (HCID).

ShortHealth certificate identifier (HCID)
Control1..1
TypeIdentifier
Summarytrue
18. DDCCCoreDataSet.certificate.ddccid
Definition

DDCC Identifier

ShortDDCC Identifier
Control0..1
TypeIdentifier
Summarytrue
20. DDCCCoreDataSet.certificate.version
Definition

Certificate schema version

ShortCertificate schema version
NoteThis is a business version Id, not a resource version Id (see discussion)
Control1..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
22. DDCCCoreDataSet.certificate.period
Definition

Certificate validity period.

ShortCertificate Validity Period
Control0..1
TypePeriod
Invariantsele-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))
24. DDCCCoreDataSet.certificate.period.start
Definition

Start date of certificate validity.


The start of the period. The boundary is inclusive.

ShortCertificate valid fromStarting time with inclusive boundary
Comments

If the low element is missing, the meaning is that the low boundary is not known.

Control0..1
This element is affected by the following invariants: per-1
TypedateTime
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
26. 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.

ShortCertificate 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.

Control0..1
This element is affected by the following invariants: per-1
TypedateTime
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Meaning if MissingIf the end of the period is missing, it means that the period is ongoing
Invariantsele-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.

ShortDDCC Core Data Set Logical Model
Control0..*
Is Modifierfalse
Logical ModelInstances of this logical model are not marked to be the target of a Reference
2. DDCCCoreDataSet.name
Definition

The full name of the person.

ShortName
Control1..1
Typestring
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
4. DDCCCoreDataSet.birthDate
Definition

The person's date of birth (DOB) if known. If unknown, use given DOB for administrative purposes

ShortDate of birth
Control0..1
Typedate
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
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).

ShortUnique identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
Summarytrue
8. DDCCCoreDataSet.certificate
Definition

Metadata associated with the certificate

ShortCertificate Metadata
Control0..1
TypeBackboneElement
Summarytrue
Invariantsele-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.

ShortUnique id for inter-element referencing
Control0..1
Typestring
Is Modifierfalse
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
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.

ShortAdditional 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.

Control0..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-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())
SlicingThis element introduces a set of slices on DDCCCoreDataSet.certificate.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 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).

    ShortExtensions 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.

    Control0..*
    TypeExtension
    Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
    Summarytrue
    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 Namesextensions, user content, modifiers
    Invariantsele-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.

    ShortCertificate issuer
    Control1..1
    TypeReference(DDCC Organization)
    Summarytrue
    18. DDCCCoreDataSet.certificate.kid
    Definition

    Key ID

    ShortKey ID used to verify the signature of the certificate
    Control0..1
    Typestring
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    20. DDCCCoreDataSet.certificate.hcid
    Definition

    Health certificate identifier (HCID).

    ShortHealth certificate identifier (HCID)
    Control1..1
    TypeIdentifier
    Summarytrue
    22. DDCCCoreDataSet.certificate.ddccid
    Definition

    DDCC Identifier

    ShortDDCC Identifier
    Control0..1
    TypeIdentifier
    Summarytrue
    24. DDCCCoreDataSet.certificate.version
    Definition

    Certificate schema version

    ShortCertificate schema version
    NoteThis is a business version Id, not a resource version Id (see discussion)
    Control1..1
    Typestring
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    26. DDCCCoreDataSet.certificate.period
    Definition

    Certificate validity period.

    ShortCertificate Validity Period
    Control0..1
    TypePeriod
    Invariantsele-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.

    ShortUnique id for inter-element referencing
    Control0..1
    Typestring
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    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.

    ShortAdditional 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.

    Control0..*
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Alternate Namesextensions, user content
    Invariantsele-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())
    SlicingThis element introduces a set of slices on DDCCCoreDataSet.certificate.period.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 32. DDCCCoreDataSet.certificate.period.start
      Definition

      Start date of certificate validity.

      ShortCertificate valid from
      Comments

      If the low element is missing, the meaning is that the low boundary is not known.

      Control0..1
      This element is affected by the following invariants: per-1
      TypedateTime
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-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.

      ShortCertificate 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.

      Control0..1
      This element is affected by the following invariants: per-1
      TypedateTime
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Meaning if MissingIf the end of the period is missing, it means that the period is ongoing
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))