The worm first appeared on 20 January 1999.[8] Media reports of the worm started coming in from the United States and Europe, in addition to numerous complaints on newsgroups from users that had become infected with the worm.[9] Asia Pulse reported 74 cases of the virus from Japan in February, and 181 cases were reported in March—a monthly record at the time.[10][11] On 3 March 1999, a Tokyo job company accidentally sent 4000 copies of the virus to 30 universities in Japan.[12]

Dan Schrader of Trend Micro said that Happy99 was the single most commonly reported virus in their system for the month of March.[13] A virus bulletin published in February 2000 reported that Happy99 caused reports of file-infecting malware to reach over 16% in April 1999.[14] Sophos listed Happy99 among the top ten viruses reported in the year of 1999.[15] Eric Chien, head of research at Symantec, reported that the worm was the second most reported virus in Europe for 2000.[16] Marius Van Oers, a researcher for Network Associates, referred to Happy99 as "a global problem", saying that it was one of the most commonly reported viruses in 1999.[17] When virus researcher Craig Schmugar posted a fix for the virus on his website, a million people downloaded it.[18]  - https://en.wikipedia.org/wiki/Happy99