On May 4, 2000, users of Windows computers began receiving an email with a malicious attachment. Within just ten days, some fifty million infections were reported, and it has been estimated that as many as 10% of the internet-connected computers in the world ultimately caught the ILOVEYOU virus.
The economic impact was equally massive, with some putting the eventual cost of removing the infection and recovering deleted files from backups as high as $10 billion (£8.3 billion) by the time the dust had settled. The Pentagon, the CIA and the U.K. Parliament all closed down their email systems in response to the incident.
Unsurprisingly, ILOVEYOU dominated the news headlines globally at the time. The spread of the infection was accelerated because victims were largely complacent to the threat it posed initially, and the devastating impact of the virus would have been significantly reduced if expert warnings from years before had been heeded. Substitute COVID-19 for ILOVEYOU and those words could so easily apply today.