George M. Groutas via Flickr

After years of struggle, the production of seasonal flu vaccine in the United States has entered the modern era. On 20 November, the Food and Drug Administration (FDA) approved its first seasonal flu vaccine made in cell culture, rather than in fertilized chicken eggs.

The vaccine, Flucelvax, is made by the Swiss pharmaceutical company Novartis and was approved by the European Union in 2007 under the name Optaflu. The United States is the largest single market for seasonal flu vaccines, accounting for 40% of sales across in major markets in 2009.

Decades of experience have established the safety and efficacy of the chicken-egg approach. But eggs are slow and their supply is limited, making it difficult to respond to emergencies, such as the H1N1 ‘swine flu’ pandemic of 2009 (see ‘The virus grower’ and ‘Flu decisions loom for new flu strain‘). With each flu emergency comes renewed calls — and government subsidies — for alternative methods of flu vaccine production. Still, the FDA and its advisers previously balked at cell-culture grown vaccines, citing the need for additional safety data.

Flucelvax is made in Madin-Darby canine kidney epithelial cells, a well-known cell line harvested from a female Cocker Spaniel in 1958 and grown in the lab ever since. Flucelvax cells will be grown in a $1 billion manufacturing plant in Holly Spring, North Carolina paid for in part by the US Department of Health and Human Services.