An average of 48,000 folks in New York state have HIV but remain unaware of it, according to a recent number-crunching Gay Men's Health Crisis report, the first estimates of undiagnosed HIV in New York. "Those infected with HIV but don't know it are the engine that drives the AIDS epidemic," said GMHC's acting head Ronald Johnson. "Fifty thousand undiagnosed people can't be ignored." Nationwide, as of 1996, HIVers not-in-the-know made up about 240,000, according to the Centers for Disease Control and Prevention.