The U.S. Department of Health and Human Services (HHS) has announced a “milestone” in fighting influenza: a U.S. facility has been approved by the Food & Drug Administration (FDA) to manufacture vaccines using a cell-based technology.

Though a cell-based flu vaccine named Flucelvax was approved by the FDA in 2012, the approval of this particular facility would increase the capacity for seasonal influenza vaccine production “by at least 50 million doses,” an HHS statement reads.

Cell-based flu vaccines, or cell culture technology, are an alternative to the traditional egg-based process used to make regular flu vaccines. They are produced by growing viruses in animal cells. The main difference between them and regular flu vaccines is that the influenza A and B viruses are grown in mammalian cells rather than hens’ eggs. According to the Centers for Disease Control and Prevention (CDC), cell-based flu vaccines are being developed due to a higher level of flexibility over egg-based vaccines. This process would also provide a faster way to develop vaccines in the case of a flu pandemic, as the cells used are frozen and stored to ensure availability.

The cell-based technology that has been approved is located at a facility in Holly Springs, North Carolina. The FDA’s approval of Flucelvax in 2012 allowed this technique to be used for the first time throughout the U.S., though it’s been available in various European countries for some time. Now, the Novartis Holly Springs facility will be the first in the U.S. to manufacture Flucelvax. “This new capability demonstrates the effectiveness of a multi-use approach to emergency preparedness,” Robin Robinson, Director and Deputy Assistant Secretary for Preparedness and Response (ASPR) at Biomedical Advanced Research and Development Authority, said in a statement.

"Cell-culture technology is the first major advancement in influenza vaccine production in the US in more than 40 years. We are proud to be at the forefront of this innovation, which will allow us to deliver on our public health and health security commitments," Andrin Oswald, Division Head of Novartis Vaccines, said in a news release. "With this award-winning, state-of-the-art facility, we will be able to not only offer US consumers an antibiotic- and preservative-free alternative for the yearly seasonal flu vaccination, but also be better prepared for future pandemic threats." Cell-based vaccines have been used for polio, rotavirus, hepatitis, smallpox, rubella and chickenpox.