Older handsets were relatively immune from airborne viruses because they lacked functionality. However, Internet-enabled smartphones are facile hosts for infection and attack. For example, the 911 virus flooded Tokyo's emergency response phone system using an SMS message. The message, which hit more than 100,000 mobile phones, invited recipients to visit a web page. Unfortunately, when the users attempted to visit the web site, they activated a script that caused the phones to call 110, which is Tokyo's equivalent of the 911 emergency number in the United States. Thus, the virus could have indirectly resulted in deaths by denying emergency services.