Trial to Evaluate the Immunogenicity and Safety of Panblok® (H7 rHA) in Healthy Adults Aged 18 and Older

All currently licensed influenza vaccines in the United States are produced in embryonated hen's eggs. There are several well-recognized disadvantages to the use of eggs as the substrate for influenza vaccine. Eggs require specialized manufacturing facilities and could be difficult to scale up rapidly in response to an emerging need such as a pandemic. It is usually necessary to adapt candidate vaccine viruses for high-yield growth in eggs, a process that can be time consuming, is not always successful, and can select receptor variants that may have suboptimal immunogenicity. In addition, agricultural diseases that affect 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 has been identified as a high-priority objective. One potential alternative method for production of influenza vaccine is expression of the influenza virus hemagglutinin (HA) using recombinant DNA techniques. This alternative avoids dependence on eggs and is very efficient because of the high levels of protein expression under the control of the baculovirus polyhedrin promoter.