Vaccine Production in Cells

For decades, vaccines have provided effective protection from influenza for Americans. While they have traditionally been produced in chicken eggs, a new technology-cell-based vaccine production-could save hundreds of thousands of lives in the event of an outbreak of pandemic influenza, or some other infectious disease.

The new approach would use mammalian cells (kidney cells are often used) to grow the influenza viruses. Cell-based vaccine production could more easily meet "surge capacity needs" because cells could be frozen and stored in advance of an epidemic or developed rapidly in response to an epidemic. Cell-based vaccine production dramatically reduces the possibility for contamination and promises to be more reliable, flexible, and expandable than egg-based methods.

In place of eggs, cell-based vaccine production utilizes laboratory-grown cell lines that are capable of hosting a growing virus. The virus is injected into the cells where it multiplies. The cells' outer walls are removed, harvested, purified, and inactivated. A vaccine can be produced in a matter of weeks. Polio vaccine is currently produced using the cell-based method.

While both methods could produce an equally effective vaccine, egg-based production is physically limited by the availability of specialized eggs and alone may not be able to meet the accelerated demands of a global influenza pandemic. Cell-based vaccines offer the potential to increase production surge capacity and save lives:

• In order to produce 300 million doses of vaccine, egg-based production would require some 900 million eggs. In the case of an avian flu pandemic, egg-producing flocks could decline, jeopardizing vaccine production capabilities.
• While eggs are perishable, cell lines can be safely kept frozen indefinitely, increasing the capability to rapidly produce vaccines if an influenza pandemic were to occur.
• Vaccine manufacturers are able to bypass the steps needed to adapt the virus strains to grow in eggs
• People allergic to eggs cannot receive vaccines produced from chicken eggs, but can be immunized with a cell-based vaccine.

In March 2005, the Department of Health and Human Services issued a five-year contract to Sanofi-Pasteur for $97.1 million to develop cell-based influenza vaccine technology and conduct clinical trials, with the goal of obtaining an FDA license for this vaccine. Under this advanced development contract, the company has committed to develop a plan to establish a U.S. cell-based influenza vaccine manufacturing facility, capable of producing at least 300 million doses of a pandemic influenza vaccine over a one year period.

In May 2006, HHS awarded five contracts totaling more than $1 billion to accelerate development and production of new technologies for influenza vaccines within the U.S. These five contracts support the advanced development of cell-based production technologies for influenza vaccines and will help to modernize and strengthen the nation's influenza vaccine production by creating an alternative to producing influenza vaccines in eggs. The funds are part of $3.3 billion proposed by former President Bush and appropriated by Congress to HHS for fiscal year 2006 to help the nation prepare for a pandemic. (News release).

In March 2010, the U.S. Food and Drug Administration issued final guidance to help manufacturers who are developing safe and effective cell-based viral vaccines to address emerging and pandemic threats. (News release).