diff --git a/terraform/dynamodb.tf b/terraform/dynamodb.tf
index 5bf01ae20..22d60dcb7 100644
--- a/terraform/dynamodb.tf
+++ b/terraform/dynamodb.tf
@@ -68,6 +68,11 @@ resource "aws_dynamodb_table" "delta-dynamodb-table" {
     type = "S"
   }
 
+  attribute {
+    name = "ImmsID"
+    type = "S"
+  }
+
   attribute {
     name = "Operation"
     type = "S"
@@ -102,6 +107,12 @@ resource "aws_dynamodb_table" "delta-dynamodb-table" {
     projection_type = "ALL"
   }
 
+  global_secondary_index {
+    name            = "ImmunisationIdIndex"
+    hash_key        = "ImmsID"
+    projection_type = "ALL"
+  }
+
   point_in_time_recovery {
     enabled = var.environment == "prod"
   }