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: DDCCGenerateHealthCertificateParameters - Detailed Descriptions

Draft as of 2025-03-10

Definitions for the DDCCGenerateHealthCertificateParameters resource profile.

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

0. Parameters
Definition

This resource is a non-persisted resource used to pass information into and back from an operation. It has no other use, and there is no RESTful endpoint associated with it.

ShortOperation Request or Response
Comments

The parameters that may be used are defined by the OperationDefinition resource.

Control0..*
Is Modifierfalse
Summaryfalse
2. Parameters.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. Parameters.parameter
Definition

A parameter passed to or received from the operation.

ShortOperation Parameter
Control10..*
TypeBackboneElement
Is Modifierfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
inv-1: A parameter must have one and only one of (value, resource, part) ((part.exists() and value.empty() and resource.empty()) or (part.empty() and (value.exists() xor resource.exists())))
inv-1: A parameter must have one and only one of (value, resource, part) ((part.exists() and value.empty() and resource.empty()) or (part.empty() and (value.exists() xor resource.exists())))
SlicingThis element introduces a set of slices on Parameters.parameter. The slices areUnordered and Closed, and can be differentiated using the following discriminators:
  • value @ name
  • 6. Parameters.parameter.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())
    8. Parameters.parameter.name
    Definition

    The name of the parameter (reference to the operation definition).

    ShortName from the definition
    Control1..1
    Typestring
    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()))
    10. Parameters.parameter:ddccResponse
    Slice NameddccResponse
    Definition

    A parameter passed to or received from the operation.

    ShortOperation Parameter
    Control10..1*
    TypeBackboneElement
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    inv-1: A parameter must have one and only one of (value, resource, part) ((part.exists() and value.empty() and resource.empty()) or (part.empty() and (value.exists() xor resource.exists())))
    inv-1: A parameter must have one and only one of (value, resource, part) ((part.exists() and value.empty() and resource.empty()) or (part.empty() and (value.exists() xor resource.exists())))
    12. Parameters.parameter:ddccResponse.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())
    14. Parameters.parameter:ddccResponse.name
    Definition

    The name of the parameter (reference to the operation definition).

    ShortName from the definition
    Control1..1
    Typestring
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Pattern Valueresponse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    16. Parameters.parameter:ddccResponse.resource
    Definition

    Sets expectations for supported capabilities for questionnaire responses for SDC-conformant systems.


    If the parameter is a whole resource.

    ShortSDC Questionnaire ResponseIf parameter is a whole resource
    Comments

    The QuestionnaireResponse contains enough information about the questions asked and their organization that it can be interpreted somewhat independently from the Questionnaire it is based on. I.e. You don't need access to the Questionnaire in order to extract basic information from a QuestionnaireResponse.


    When resolving references in resources, the operation definition may specify how references may be resolved between parameters. If a reference cannot be resolved between the parameters, the application should fall back to it's general resource resolution methods.

    Control10..1
    This element is affected by the following invariants: inv-1
    TypeChoice of: QuestionnaireResponse(DDCC Questionnaire Response), Bundle, Resource
    Is Modifierfalse
    Summarytrue
    Alternate NamesForm, QuestionnaireAnswers, Form Data