Add disease_types column to ConsentFormProgramme model

This allows us to determine the disease types for the consent form in the controller and set that
when creating the consent form, which will eventually determine which questions the parent sees.
This is required now becasue we are adding a new consent flow for MMRV which is a "variant" of the
programme MMR. Hence the programme type alone is insufficient to determine which consent journey is
displayed.

Author: murugapl

app/models/consent_form_programme.rb

@@ -5,6 +5,7 @@
 # Table name: consent_form_programmes
 #
 #  id                 :bigint           not null, primary key
+#  disease_types      :enum             is an Array
 #  notes              :text             default(""), not null
 #  programme_type     :enum             not null
 #  reason_for_refusal :integer
@@ -36,7 +37,11 @@ class ConsentFormProgramme < ApplicationRecord
   delegate :flu?, :hpv?, :menacwy?, :mmr?, :td_ipv?, to: :programme
 
   def disease_types
-    # TODO: Update this when we allow parents to submit consent for MMRV.
+    # Use database column if populated, otherwise fall back to default logic
+    # for records created before disease_types column was added
+    db_value = super
+    return db_value if db_value.present?
+
     if programme_type == "mmr"
       Programme::Variant::DISEASE_TYPES["mmr"]
     else
@@ -46,7 +51,7 @@ def disease_types
 
   def vaccines
     VaccineCriteria.from_consentable(self).apply(
-      Vaccine.active.where(programme_type:)
+      Vaccine.active.where(programme_type:, disease_types:)
     )
   end
 

db/migrate/20260218163043_add_disease_types_to_consent_form_programmes.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class AddDiseaseTypesToConsentFormProgrammes < ActiveRecord::Migration[8.1]
+  def change
+    add_column :consent_form_programmes,
+               :disease_types,
+               :enum,
+               enum_type: :disease_type,
+               array: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_02_17_111256) do
+ActiveRecord::Schema[8.1].define(version: 2026_02_18_163043) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
   enable_extension "pg_trgm"
@@ -202,6 +202,7 @@
 
   create_table "consent_form_programmes", force: :cascade do |t|
     t.bigint "consent_form_id", null: false
+    t.enum "disease_types", array: true, enum_type: "disease_type"
     t.text "notes", default: "", null: false
     t.enum "programme_type", null: false, enum_type: "programme_type"
     t.integer "reason_for_refusal"

spec/factories/consent_form_programmes.rb

@@ -5,6 +5,7 @@
 # Table name: consent_form_programmes
 #
 #  id                 :bigint           not null, primary key
+#  disease_types      :enum             is an Array
 #  notes              :text             default(""), not null
 #  programme_type     :enum             not null
 #  reason_for_refusal :integer
@@ -26,6 +27,13 @@
   factory :consent_form_programme do
     consent_form
     programme { Programme.sample }
+    disease_types do
+      if programme.mmr?
+        programme.variants.sample.disease_types
+      else
+        Programme::DISEASE_TYPES[programme.type]
+      end
+    end
 
     trait :given do
       response { "given" }

spec/factories/consent_forms.rb

@@ -146,6 +146,14 @@
       evaluator.programmes.each do |programme|
         consent_form.consent_form_programmes.build(
           programme:,
+          disease_types:
+            (
+              if programme.mmr?
+                programme.variants.sample.disease_types
+              else
+                Programme::DISEASE_TYPES[programme.type]
+              end
+            ),
           response: evaluator.response
         )
       end

spec/models/consent_form_programme_spec.rb

@@ -5,6 +5,7 @@
 # Table name: consent_form_programmes
 #
 #  id                 :bigint           not null, primary key
+#  disease_types      :enum             is an Array
 #  notes              :text             default(""), not null
 #  programme_type     :enum             not null
 #  reason_for_refusal :integer
@@ -30,6 +31,12 @@
 
   describe "#vaccines" do
     context "when there are MMR and MMRV vaccines" do
+      before do
+        consent_form_programme.update!(
+          disease_types: Programme::Variant::DISEASE_TYPES[programme.type]
+        )
+      end
+
       it "only returns MMR vaccines" do
         # Ensure that the MMRV vaccines do actually exist!
         expect(Vaccine.where(brand: %w[ProQuad Priorix-Tetra]).count).to eq(2)