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/tree/main and changes regularly. See the Directory of published versions

Resource Profile: DDCCFolder - Detailed Descriptions

Draft as of 2025-03-10

Definitions for the DDCCFolder resource profile.

Guidance on how to interpret the contents of this table can be found here

0. List
Definition

A list is a curated collection of resources.

ShortA list is a curated collection of resources
Control0..*
Is Modifierfalse
Summaryfalse
Alternate NamesCollection, WorkingList, Organizer
Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (text.`div`.exists())
lst-1: A list can only have an emptyReason if it is empty (emptyReason.empty() or entry.empty())
lst-2: The deleted flag can only be used if the mode of the list is "changes" (mode = 'changes' or entry.deleted.empty())
lst-3: An entry date can only be used if the mode of the list is "working" (mode = 'working' or entry.date.empty())
lst-1: A list can only have an emptyReason if it is empty (emptyReason.empty() or entry.empty())
lst-2: The deleted flag can only be used if the mode of the list is "changes" (mode = 'changes' or entry.deleted.empty())
lst-3: An entry date can only be used if the mode of the list is "working" (mode = 'working' or entry.date.empty())
2. List.implicitRules
Definition

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

ShortA set of rules under which this content was created
Comments

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

Control0..1
Typeuri
Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
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()))
4. List.extension
Definition

An Extension


May be used to represent additional information that is not part of the basic definition of the resource. 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.

ShortExtensionAdditional 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.

Control10..*
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 List.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 6. List.extension:designationType
    Slice NamedesignationType
    Definition

    Expresses contentType of submissionSet or the codeList of a Folder. Usually expressed in LOINC or SNOMED.

    ShortClinical code of the List
    Control1..*
    This element is affected by the following invariants: ele-1
    TypeExtension(Clinical code of the List) (Extension Type: CodeableConcept)
    Is Modifierfalse
    Must Supporttrue
    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())
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    8. List.extension:designationType/ddccDesignation
    Slice NamedesignationType/ddccDesignation
    Definition

    Expresses contentType of submissionSet or the codeList of a Folder. Usually expressed in LOINC or SNOMED.

    ShortClinical code of the List
    Control1..1
    This element is affected by the following invariants: ele-1
    TypeExtension(Clinical code of the List) (Extension Type: CodeableConcept)
    Is Modifierfalse
    Must Supporttrue
    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())
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    10. List.extension:designationType/ddccDesignation.extension
    Definition

    An Extension


    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.

    ShortExtensionAdditional 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..0*
    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 List.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 12. List.extension:designationType/ddccDesignation.url
      Definition

      Source of the definition for the extension code - a logical name or a URL.

      Shortidentifies the meaning of the extension
      Comments

      The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

      Control1..1
      Typeuri
      Is Modifierfalse
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      Fixed Valuehttps://profiles.ihe.net/ITI/MHD/StructureDefinition/ihe-designationType
      14. List.extension:designationType/ddccDesignation.value[x]
      Definition

      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

      ShortValue of extension
      Control10..1
      TypeCodeableConcept, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, Coding, SampledData, id, positiveInt, Distance, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ParameterDefinition, dateTime, code, string, Contributor, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, Signature, unsignedInt, time
      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      16. List.extension:designationType/ddccDesignation.value[x].coding
      Definition

      A reference to a code defined by a terminology system.

      ShortCode defined by a terminology system
      Comments

      Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

      Control10..1*
      TypeCoding
      Is Modifierfalse
      Summarytrue
      Requirements

      Allows for alternative encodings within a code system, and translations to other code systems.

      Pattern Value{
        "system" : "http://smart.who.int/ddcc/CodeSystem/DDCCFolderDesignationTypeCodesystem",
        "code" : "ddcc"
      }
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      18. List.modifierExtension
      Definition

      An Extension


      May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it 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 is allowed to 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).

      ShortExtensionExtensions that cannot be ignored
      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..0*
      TypeExtension
      Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
      Summaryfalse
      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
      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())
      20. List.identifier
      Definition

      Identifier for the List assigned for business purposes outside the context of FHIR.

      ShortBusiness identifier
      NoteThis is a business identifier, not a resource identifier (see discussion)
      Control0..*
      TypeIdentifier
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      SlicingThis element introduces a set of slices on List.identifier. The slices areUnordered and Open, and can be differentiated using the following discriminators:
      • value @ use
      • 22. List.identifier:uniqueId
        Slice NameuniqueId
        Definition

        An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.


        Identifier for the List assigned for business purposes outside the context of FHIR.

        ShortAn identifier intended for computationBusiness identifier
        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..1*
        This element is affected by the following invariants: ele-1
        TypeIdentifier(uniqueId Identifier)
        Is Modifierfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        24. List.identifier:entryUUID
        Slice NameentryUUID
        Definition

        An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.


        Identifier for the List assigned for business purposes outside the context of FHIR.

        ShortAn identifier intended for computationBusiness identifier
        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..*
        This element is affected by the following invariants: ele-1
        TypeIdentifier(entryUUID Identifier)
        Is Modifierfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        26. List.status
        Definition

        Indicates the current state of this list.

        Shortcurrent | retired | entered-in-error
        Comments

        This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

        Control1..1
        BindingThe codes SHALL be taken from ListStatushttp://hl7.org/fhir/ValueSet/list-status|4.0.1
        (required to http://hl7.org/fhir/ValueSet/list-status|4.0.1)

        The current state of the list.

        Typecode
        Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
        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()))
        28. List.mode
        Definition

        How this list was prepared - whether it is a working list that is suitable for being maintained on an ongoing basis, or if it represents a snapshot of a list of items from another source, or whether it is a prepared list where items may be marked as added, modified or deleted.

        Shortworking | snapshot | changes
        Comments

        This element is labeled as a modifier because a change list must not be misunderstood as a complete list.

        Control1..1
        BindingThe codes SHALL be taken from ListModehttp://hl7.org/fhir/ValueSet/list-mode|4.0.1
        (required to http://hl7.org/fhir/ValueSet/list-mode|4.0.1)

        The processing mode that applies to this list.

        Typecode
        Is Modifiertrue because If set to "changes", the list is considered incomplete, while the other two codes indicate the list is complete, which changes the understanding of the elements listed
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Requirements

        Lists are used in various ways, and it must be known in what way it is safe to use them.

        Pattern Valueworking
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        30. List.code
        Definition

        This code defines the purpose of the list - why it was created.

        ShortWhat the purpose of this list is
        Comments

        If there is no code, the purpose of the list is implied where it is used, such as in a document section using Document.section.code.

        Control10..1
        BindingThe codes SHALL be taken from For example codes, see MHD List Types ValueSethttp://hl7.org/fhir/ValueSet/list-example-codes
        (required to https://profiles.ihe.net/ITI/MHD/ValueSet/MHDlistTypesVS)
        TypeCodeableConcept
        Is Modifierfalse
        Summarytrue
        Requirements

        Lists often contain subsets of resources rather than an exhaustive list. The code identifies what type of subset is included.

        Pattern Value{
          "coding" : [{
            "system" : "https://profiles.ihe.net/ITI/MHD/CodeSystem/MHDlistTypes",
            "code" : "folder"
          }]
        }
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        32. List.subject
        Definition

        The common subject (or patient) of the resources that are in the list if there is one.

        ShortIf all resources have the same subject
        Comments

        Some purely arbitrary lists do not have a common subject, so this is optional.

        Control10..1
        TypeReference(DDCC Patient, Patient, Group, Device, Location)
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Requirements

        The primary purpose of listing the subject explicitly is to help with finding the right list.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        34. List.subject.reference
        Definition

        A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

        ShortLiteral reference, Relative, internal or absolute URL
        Comments

        Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

        Control10..1
        This element is affected by the following invariants: ref-1
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supporttrue
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        36. List.encounter
        Definition

        The encounter that is the context in which this list was created.

        ShortContext in which list created
        Control0..01
        TypeReference(Encounter)
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        38. List.source
        Definition

        The entity responsible for deciding what the contents of the list were. Where the list was created by a human, this is the same as the author of the list.

        ShortWho and/or what defined the list contents (aka Author)
        Comments

        The primary source is the entity that made the decisions what items are in the list. This may be software or user.

        Control0..01
        TypeReference(Practitioner, PractitionerRole, Patient, Device)
        Is Modifierfalse
        Summarytrue
        Requirements

        Allows follow-up as well as context.

        Alternate NamesAuthor
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        40. List.orderedBy
        Definition

        What order applies to the items in the list.

        ShortWhat order the list has
        Comments

        Applications SHOULD render ordered lists in the order provided, but MAY allow users to re-order based on their own preferences as well. If there is no order specified, the order is unknown, though there may still be some order.

        Control0..01
        BindingThe codes SHOULD be taken from ListOrderCodeshttp://hl7.org/fhir/ValueSet/list-order
        (preferred to http://hl7.org/fhir/ValueSet/list-order)

        What order applies to the items in a list.

        TypeCodeableConcept
        Is Modifierfalse
        Summaryfalse
        Requirements

        Important for presentation and rendering. Lists may be sorted to place more important information first or to group related entries.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        42. List.note
        Definition

        Comments that apply to the overall list.

        ShortComments about the list
        Control0..1*
        TypeAnnotation
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        44. List.emptyReason
        Definition

        If the list is empty, why the list is empty.

        ShortWhy list is empty
        Comments

        The various reasons for an empty list make a significant interpretation to its interpretation. Note that this code is for use when the entire list has been suppressed, and not for when individual items are omitted - implementers may consider using a text note or a flag on an entry in these cases.

        Control0..01
        This element is affected by the following invariants: lst-1
        BindingThe codes SHOULD be taken from ListEmptyReasonshttp://hl7.org/fhir/ValueSet/list-empty-reason
        (preferred to http://hl7.org/fhir/ValueSet/list-empty-reason)

        If a list is empty, why it is empty.

        TypeCodeableConcept
        Is Modifierfalse
        Summaryfalse
        Requirements

        Allows capturing things like "none exist" or "not asked" which can be important for most lists.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))