diff --git a/backend/community/serializers.py b/backend/community/serializers.py
index 63b6b9d..7aa91c0 100644
--- a/backend/community/serializers.py
+++ b/backend/community/serializers.py
@@ -173,6 +173,7 @@ class AdminActivitySerializer(serializers.ModelSerializer):
     class Meta:
         model = Activity
         fields = '__all__'
+        read_only_fields = ['author', 'created_at', 'current_signups']
 
 class AdminTopicSerializer(serializers.ModelSerializer):
     content = serializers.CharField(style={'base_template': 'textarea.html'})
@@ -180,3 +181,4 @@ class AdminTopicSerializer(serializers.ModelSerializer):
     class Meta:
         model = Topic
         fields = '__all__'
+        read_only_fields = ['author', 'created_at', 'updated_at', 'view_count', 'is_verified_owner']