diff --git a/apollo/submissions/filters.py b/apollo/submissions/filters.py
index ebccea04a..0b5be0ba6 100644
--- a/apollo/submissions/filters.py
+++ b/apollo/submissions/filters.py
@@ -58,43 +58,40 @@ def __init__(self, *args, **kwargs):
             self.participant_set_id = participant_set_id
             self.filter_on_locations = filter_on_locations
 
-            kwargs['choices'] = _make_choices(sample_choices, _('Sample'))
+            kwargs["choices"] = _make_choices(sample_choices, _("Sample"))
             super().__init__(*args, **kwargs)
 
         def filter_by_locations(self, query, value):
+            # Join with Location model if not already present
             if utils.has_model(query, models.Location):
                 query1 = query
             else:
                 query1 = query.join(models.Submission.location)
 
-            sample_locations = models.Participant.query.filter_by(
-                participant_set_id=participant_set_id
-            ).join(
-                models.Participant.samples
-            ).filter(
-                models.Sample.participant_set_id == participant_set_id,
-                models.Sample.id == value
-            ).with_entities(
-                models.Participant.location_id
+            locations_subquery = (
+                models.Sample.query.filter(
+                    models.Sample.id == value, models.Sample.participant_set_id == participant_set_id
+                )
+                .join(models.Participant.samples)
+                .with_entities(models.Participant.location_id.label("loc_id"))
+                .subquery()
             )
+            query2 = query1.join(locations_subquery, models.Submission.location_id == locations_subquery.c.loc_id)
 
-            query2 = query1.filter(
-                models.Submission.location_id.in_(sample_locations)
-            )
             return query2
 
         def filter_by_participants(self, query, value):
-            participants_in_sample = models.Participant.query.join(
-                models.Participant.samples
-            ).filter(
-                models.Participant.participant_set_id == participant_set_id,
-                models.Sample.id == value
+            participants_subquery = (
+                models.Sample.query.filter(
+                    models.Sample.id == value, models.Sample.participant_set_id == participant_set_id
+                )
+                .join(models.Participant.samples)
+                .with_entities(models.Participant.id.label("part_id"))
+                .subquery()
+            )
+            query2 = query.join(
+                participants_subquery, models.Submission.participant_id == participants_subquery.c.part_id
             )
-            participant_ids = list(
-                chain(*participants_in_sample.with_entities(
-                    models.Participant.id).all()))
-            query2 = query.filter(
-                models.Submission.participant_id.in_(participant_ids))
 
             return query2