The US Food and Drug Administration (FDA) issued final recommendations to increase the supply of safe and effective influenza vaccines for both seasonal and pandemic use.

FDA's goal with the guidances is to outline the regulatory pathways for the rapid development and approval of these products, a FDA press release stated.

"FDA continues its commitment to help increase the supply of influenza vaccines and support the development of new approaches to vaccine production," said Jesse L. Goodman, M.D., M.P.H., director of FDA's Center for Biologics Evaluation and Research (CBER). "Having additional manufacturers of licensed influenza vaccines will enhance the capacity to produce more doses of seasonal influenza vaccines, as well as contribute to the nation's pandemic preparedness, one of our top priorities."

In March 2006, FDA issued two draft guidance documents for public comment - one for seasonal influenza vaccines and another for pandemic influenza vaccines. The draft documents outline specific approaches for manufacturers to develop new vaccines that are safe, pure, and potent. The final guidances reflect public input, including vaccine companies and public health officials.

Both guidances recommend using recent technologies such as cell culture and recombinant manufacturing to enhance the development and evaluation of vaccines. They also recommend adding substances that improve the immune response from the vaccine (novel adjuvants).

The guidances describe conventional and accelerated approval pathways to vaccine licensure. Companies selecting the conventional pathway must provide clinical evidence that the vaccine prevents influenza. Adequate and well-controlled clinical trials are also required for accelerated approval but companies may use a biological indicator - such as immune response to the vaccine - to predict effectiveness, an approach that may reduce the vaccine's development time. Further clinical studies are then required to verify the vaccine's clinical benefit.

The guidances indicate that manufacturers should submit a new Biologics License Application (BLA) for the initial licensure of a pandemic or seasonal influenza vaccine to ensure that each pandemic and seasonal vaccine has its own trade name and labelling.

For companies with U.S. licensed seasonal influenza vaccines, the pandemic guidance outlines the regulatory pathway for obtaining licensure for a new pandemic vaccine in which the manufacturing process is the same as for the seasonal vaccine. For manufacturers developing vaccines using a new manufacturing process, both guidance documents explain the process for obtaining licensure using the accelerated approval pathway.

The guidance documents represent the FDA's ongoing efforts under its Critical Path Initiative to translate scientific advances, such as cell-culture derived and recombinant vaccine technologies, into new medical products with shorter approval timeframes.