diff --git a/octue/cloud/pub_sub/message_handler.py b/octue/cloud/pub_sub/message_handler.py
index 60124e64d..98114c3a8 100644
--- a/octue/cloud/pub_sub/message_handler.py
+++ b/octue/cloud/pub_sub/message_handler.py
@@ -414,9 +414,9 @@ def _handle_result(self, message):
         """
         logger.info("%r received an answer to question %r.", self.receiving_service, self.question_uuid)
 
-        if message["output_manifest"] is None:
-            output_manifest = None
-        else:
+        if message.get("output_manifest"):
             output_manifest = Manifest.deserialise(message["output_manifest"])
+        else:
+            output_manifest = None
 
-        return {"output_values": message["output_values"], "output_manifest": output_manifest}
+        return {"output_values": message.get("output_values"), "output_manifest": output_manifest}
diff --git a/octue/cloud/pub_sub/service.py b/octue/cloud/pub_sub/service.py
index accebf880..867a0a4d2 100644
--- a/octue/cloud/pub_sub/service.py
+++ b/octue/cloud/pub_sub/service.py
@@ -236,17 +236,16 @@ def answer(self, question, heartbeat_interval=120, timeout=30):
                 allow_save_diagnostics_data_on_crash=allow_save_diagnostics_data_on_crash,
             )
 
-            if analysis.output_manifest is None:
-                serialised_output_manifest = None
-            else:
-                serialised_output_manifest = analysis.output_manifest.to_primitive()
+            result = {"type": "result"}
+
+            if analysis.output_values is not None:
+                result["output_values"] = analysis.output_values
+
+            if analysis.output_manifest is not None:
+                result["output_manifest"] = analysis.output_manifest.to_primitive()
 
             self._send_message(
-                {
-                    "type": "result",
-                    "output_values": analysis.output_values,
-                    "output_manifest": serialised_output_manifest,
-                },
+                message=result,
                 topic=topic,
                 attributes={"question_uuid": question_uuid, "is_question": False},
                 timeout=timeout,
diff --git a/tests/cloud/pub_sub/test_service.py b/tests/cloud/pub_sub/test_service.py
index 56e29c622..215337570 100644
--- a/tests/cloud/pub_sub/test_service.py
+++ b/tests/cloud/pub_sub/test_service.py
@@ -722,7 +722,7 @@ def test_child_messages_can_be_recorded_by_parent(self):
 
         self.assertEqual(
             parent.received_messages[4],
-            {"type": "result", "output_values": "Hello! It worked!", "output_manifest": None},
+            {"type": "result", "output_values": "Hello! It worked!"},
         )
 
     def test_child_exception_message_can_be_recorded_by_parent(self):