Security vendor ScanSafe reports that based on real-time analysis of more than 5 billion Web requests and more than 10 million Web threats processed through its servers, viruses decreased by 47 percent during the month of September, this despite several new Microsoft vulnerabilities in Office, including a few zero-day attacks. The company says it blocked 158 viruses for its clients, of which 31 percent were new and 14 percent were zero-day viruses (viruses that exploited previously unannounced vulnerabilities). By comparison, the company reported an increase of 21 percent in viruses during August but said that was consistent with "seasonal" virus activity.