diff --git a/ipykernel/comm/manager.py b/ipykernel/comm/manager.py
index 358eb4092..d7b290de1 100644
--- a/ipykernel/comm/manager.py
+++ b/ipykernel/comm/manager.py
@@ -119,7 +119,8 @@ def comm_close(self, stream, ident, msg):
         comm = self.get_comm(comm_id)
         if comm is None:
             return
-
+        
+        self.comms[comm_id]._closed = True
         del self.comms[comm_id]
 
         try: