It turned out that the virus hit about 100,000 computers and caused problems at 250 companies. Not a picnic, but given that there are an estimated 40 million computers in the United States, hardly an epidemic either. Antivirus software makers like to say that everyone everywhere should own an antivirus program because 45,000 viruses are lurking out there. But the truth is that approximately 44,700 of the 45,000 viruses will never make it to anyone's computer because they are not designed to spread, are too badly designed to spread or are so tightly controlled by their creators that they aren't released to anybody except researchers at antivirus companies. The best estimate, made by the WildList Organization, a respected international virus watch group, suggests there are about 300 viruses with the potential to infect computers and spread.
Some experts even consider that number to be on the high side.
Security experts are not sitting around waiting for the computer world's equivalent of a Jenner or Pasteur to show up. Instead, researchers are taking a page out of the preventive medicine books to come up with a possible solution to the virus threat. If computer viruses mirror images of real-life microbes, then perhaps the answer is to give networks and computers the ability to spot a viral intruder immediately and kill it. A computer immune system, if you will. At least two companies, IBM and Symantec, have joined forces to develop such immune systems.