HEMISPHERX BIOPHARMA TO PROVIDE UPDATE ON GLOBAL PANDEMIC INFLUENZA PREVENTION / TREATMENT INITIATIVES Philadelphia, PA, Monday, July 20, 2009: Hemispherx Biopharma (NYSE AMEX: HEB) will provide an update on its Influenza research initiatives via teleconference on Wednesday, July 22, 2009, at 10:00 AM EDT. Initiatives to be discussed will include experimental programs planned or underway in Pacific Rim countries, Australia, South America and the United States. Background information may be sourced at Wall Street Journal, July 18/19, 2009, p. A3. Hemispherx’s Medical Director, CEO, and the Managing Director of the Sage Group, a health care consulting firm retained by Hemispherx, will participate. Investigational products and protocols to be discussed will include Hemispherx’s Ampligen® (poly I: poly C12U), Alferon N (a natural cocktail of alpha 2 type interferons, FDA approved for treatment of refractory HPV) and Alferon LDO, an experimental formulation of Alferon-N for oral delivery. To access the conference call: U.S. Callers: 800-346-7359 International Callers: 973-528-0008 Conference Entry Code: 27781 This call will be webcast via the Company’s website at: www.hemispherx.net. A digital replay of the call will be available until August 5, 2009 by calling: U.S. Callers: 800-332-6854 International Callers: 973-528-0005 Conference Entry Code: 27781