Influenza is a highly contagious viral respiratory illness which is best prevented through vaccination. Currently, all US licensed influenza vaccines are produced in embryonated chicken eggs. The Baculovirus Expression Vector System (BEVS) technology offers several advantages over existing technology, including an exact match between the circulating virus and the antigen in the vaccine, speed, safety, versatility, and reliable scale-up. The expresSF+ insect cells are grown in the absence of serum and have been extensively qualified for safety according to ICH and US FDA guidance and for suitability for the production of recombinant proteins using BEVS. FluBlok, a recombinant hemagglutinin influenza vaccine, is composed of purified hemagglutinin protein produced using the BEVS technology. FluBlok has been shown to be safe, effective, and efficacious in human clinical studies.