Immunogenicity, Safety, Reactogenicity, Efficacy, Effectiveness and Lot Consistency of FluBlok

All currently licensed influenza vaccines in the United States were produced in embryonated hen's eggs. There were several well-recognized disadvantages to the use of eggs as the substrate for influenza vaccine. Eggs required specialized manufacturing facilities and could be difficult to scale up rapidly in response to an emerging need such as a pandemic. It was usually necessary to adapt candidate vaccine viruses for high-yield growth in eggs, a process that could be time consuming, was not always successful, and could select receptor variants that might have suboptimal immunogenicity. In addition, agricultural diseases that affected chicken flocks, and that might be an important issue in a pandemic due to an avian influenza virus strain, could easily disrupt the supply of eggs for vaccine manufacturing. Therefore, development of alternative substrates for influenza vaccine production had been identified as a high-priority objective. One potential alternative method for production of influenza vaccine was expression of the influenza virus hemagglutinin (HA) using recombinant deoxyribonucleic acid (DNA) techniques. This alternative avoided dependence on eggs and was very efficient because of the high levels of protein expression under the control of the baculovirus polyhedrin promoter.