It will ignore unread messages if you include a check for it e.g.
Code:
Private Sub Newsletters_ItemAdd(ByVal item As Object)
If Not item.UnRead Then
On Error GoTo err_Handler
Set olItem = item.Forward
olItem.BCC = "Newsletters"
olItem.sEnd
End If
lbl_Exit:
Exit Sub
err_Handler:
MsgBox Err.Number & " - " & Err.Description
GoTo lbl_Exit
End Sub