diff --git a/smash/web/migrations/0182_visitimportdata.py b/smash/web/migrations/0184_visitimportdata.py
similarity index 98%
rename from smash/web/migrations/0182_visitimportdata.py
rename to smash/web/migrations/0184_visitimportdata.py
index 415d3042c93eda457e31bf91113a36c219105976..4354c4d94bfc91db56e29903b9bfe60bd30dacea 100644
--- a/smash/web/migrations/0182_visitimportdata.py
+++ b/smash/web/migrations/0184_visitimportdata.py
@@ -7,7 +7,7 @@ import django.db.models.deletion
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('web', '0181_worker_privacy_notice_accepted'),
+        ('web', '0183_auto_20201126_1154'),
     ]
 
     operations = [
diff --git a/smash/web/migrations/0183_visitimportdata_migration.py b/smash/web/migrations/0185_visitimportdata_migration.py
similarity index 98%
rename from smash/web/migrations/0183_visitimportdata_migration.py
rename to smash/web/migrations/0185_visitimportdata_migration.py
index 9e0732e61f51aabb9d99f1fd2450303e107db49b..084b8959a12c5d6ea4f758b2bf410b838dcf86d2 100644
--- a/smash/web/migrations/0183_visitimportdata_migration.py
+++ b/smash/web/migrations/0185_visitimportdata_migration.py
@@ -93,7 +93,7 @@ def remove_old_config(apps, schema_editor):
 
 class Migration(migrations.Migration):
     dependencies = [
-        ('web', '0182_visitimportdata'),
+        ('web', '0184_visitimportdata'),
     ]
 
     operations = [
diff --git a/smash/web/migrations/0186_auto_20201127_1003.py b/smash/web/migrations/0186_auto_20201127_1003.py
new file mode 100644
index 0000000000000000000000000000000000000000..4828b280b4f13a86f37c9de9d59732e9610f936a
--- /dev/null
+++ b/smash/web/migrations/0186_auto_20201127_1003.py
@@ -0,0 +1,43 @@
+# Generated by Django 3.1.3 on 2020-11-27 10:03
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('web', '0185_visitimportdata_migration'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='studysubject',
+            name='pd_in_family',
+            field=models.BooleanField(default=None, null=True, verbose_name='PD in family'),
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='virus_test_1',
+            field=models.BooleanField(choices=[(True, 'Yes'), (False, 'No'), (None, 'N/A')], default=None, null=True, verbose_name='Visit 1 virus result'),
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='virus_test_2',
+            field=models.BooleanField(choices=[(True, 'Yes'), (False, 'No'), (None, 'N/A')], default=None, null=True, verbose_name='Visit 2 virus result'),
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='virus_test_3',
+            field=models.BooleanField(choices=[(True, 'Yes'), (False, 'No'), (None, 'N/A')], default=None, null=True, verbose_name='Visit 3 virus result'),
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='virus_test_4',
+            field=models.BooleanField(choices=[(True, 'Yes'), (False, 'No'), (None, 'N/A')], default=None, null=True, verbose_name='Visit 4 virus result'),
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='virus_test_5',
+            field=models.BooleanField(choices=[(True, 'Yes'), (False, 'No'), (None, 'N/A')], default=None, null=True, verbose_name='Visit 5 virus result'),
+        ),
+    ]
diff --git a/smash/web/models/study_subject.py b/smash/web/models/study_subject.py
index 8c4a3350222780f79ec8754c8945da9757d235a4..39c77a02dac4b98add0562649b69cb6f6f44c07e 100644
--- a/smash/web/models/study_subject.py
+++ b/smash/web/models/study_subject.py
@@ -167,9 +167,10 @@ class StudySubject(models.Model):
         verbose_name='Information sent',
         default=False
     )
-    pd_in_family = models.NullBooleanField(
+    pd_in_family = models.BooleanField(
         verbose_name='PD in family',
         default=None,
+        null=True,
     )
     brain_donation_agreement = models.BooleanField(
         default=False,
@@ -204,26 +205,31 @@ class StudySubject(models.Model):
                                                verbose_name='Endpoint reached comments'
                                                )
 
-    virus_test_1 = models.NullBooleanField(choices=BOOL_CHOICES_WITH_NONE,
-                                           verbose_name='Visit 1 virus result',
-                                           default=None
-                                           )
-    virus_test_2 = models.NullBooleanField(choices=BOOL_CHOICES_WITH_NONE,
-                                           verbose_name='Visit 2 virus result',
-                                           default=None
-                                           )
-    virus_test_3 = models.NullBooleanField(choices=BOOL_CHOICES_WITH_NONE,
-                                           verbose_name='Visit 3 virus result',
-                                           default=None
-                                           )
-    virus_test_4 = models.NullBooleanField(choices=BOOL_CHOICES_WITH_NONE,
-                                           verbose_name='Visit 4 virus result',
-                                           default=None
-                                           )
-    virus_test_5 = models.NullBooleanField(choices=BOOL_CHOICES_WITH_NONE,
-                                           verbose_name='Visit 5 virus result',
-                                           default=None
-                                           )
+    virus_test_1 = models.BooleanField(choices=BOOL_CHOICES_WITH_NONE,
+                                       verbose_name='Visit 1 virus result',
+                                       default=None,
+                                       null=True
+                                       )
+    virus_test_2 = models.BooleanField(choices=BOOL_CHOICES_WITH_NONE,
+                                       verbose_name='Visit 2 virus result',
+                                       default=None,
+                                       null=True
+                                       )
+    virus_test_3 = models.BooleanField(choices=BOOL_CHOICES_WITH_NONE,
+                                       verbose_name='Visit 3 virus result',
+                                       default=None,
+                                       null=True
+                                       )
+    virus_test_4 = models.BooleanField(choices=BOOL_CHOICES_WITH_NONE,
+                                       verbose_name='Visit 4 virus result',
+                                       default=None,
+                                       null=True
+                                       )
+    virus_test_5 = models.BooleanField(choices=BOOL_CHOICES_WITH_NONE,
+                                       verbose_name='Visit 5 virus result',
+                                       default=None,
+                                       null=True
+                                       )
     virus_test_1_updated = models.DateField(verbose_name='Visit 1 virus result date',
                                             blank=True,
                                             null=True,