For decades, drug companies have grown vaccines using chicken eggs. That’s why an outbreak of hen-killing avian flu would be such a nightmare scenario: “The whole world would consume all the chicken eggs within a couple of months,” says Guan Yi, director of the Center of Influenza Research at the University of Hong Kong. “We need to have another option.”

The answer may lie in the Raleigh suburb of Holly Springs, N.C., where CSL, an Australian company, is experimenting with growing vaccines in kidney cells taken from dogs. (No harm comes to the dogs; the cell line has been available since 1958, when researchers took tissue from a female cocker spaniel.) While egg-based vaccines have a limited shelf life, CSL—which makes more flu vaccines than anyone besides Sanofi—says it can keep the dog cells on ice in perpetuity, to respond easily to an outbreak. “That’s critical in case of a pandemic, which spreads rapidly,” says Gordon Naylor, president of the company’s vaccine subsidiary, Seqirus.

There’s an opening in the $5 billion market for seasonal flu vaccines, of which the U.S. consumes a third. Novartis sold its money-losing vaccine division to CSL for $275 million in 2014. Sanofi and Merck dissolved their flu vaccine joint venture in March. In June the Centers for Disease Control and Prevention said AstraZeneca’s FluMist hadn’t been a strong preventive measure for three years. (AstraZeneca has said it’s working with the CDC to resolve the matter.)

CSL is one of a few companies betting new technology can help meet the challenge of producing tens of millions of doses in the few months between the World Health Organization’s recommended vaccine targets and the start of flu season.
They’re also betting they can make the market more profitable. Using mammalian cells instead of chicken embryos can help create a vaccine faster and more efficiently, says Russell Basser, senior vice president for research and development at Seqirus. The Holly Springs factory can produce as many as 200 million doses of vaccine in six months, according to the U.S. Department of Health and Human Services, which contributed $700 million to its construction.

Dog cells are also cheaper, as little as half the $3.50 cost to make a dose of flu vaccine via egg, estimates UBS analyst Andrew Goodsall. That would make flu shots affordable enough for such countries as Mexico and Brazil, he says.

CSL’s dog cells aren’t the only egg alternative. Protein Sciences uses cells from caterpillars at its plant in Rockland County, N.Y. Chief Executive Officer Manon Cox says Protein’s process is faster than egg-based vaccine production, but costs are 5 to 10 times higher. While Protein could make 5 million doses of vaccine this year, Cox says, it expects to sell only 900,000. “The uptake is not there yet,” she says.

Another alternative to eggs is Nicotiana benthamiana, an Australian weed that’s a close relative of the tobacco plant. Cigarette maker Reynolds American in 2014 acquired Kentucky BioProcessing, a decade-old company that uses tobacco plants to produce pharmaceutical proteins. Medicago, backed by Philip Morris and Japanese drugmaker Mitsubishi Tanabe Pharma, says it can produce 30 million doses of tobacco-based flu vaccine a year at its plant in North Carolina but is awaiting approval from the U.S. Food and Drug Administration.

Guan, the flu research director, isn’t confident these new technologies will be able to fill the gap if a global pandemic jeopardizes the egg supply. Absent an avian flu-style scenario, egg-based flu vaccine production should readily meet seasonal demand, he says, so investments in alternatives have been a relatively tough sell.

For now, CSL can afford to keep trying, while also continuing egg-based operations. Most of the $1.2 billion profit in its most recent fiscal year came from sales of blood plasma products; the vaccine subsidiary accounted for 10 percent of its $6.1 billion in revenue. In May, CSL won FDA approval for a dog cell-based vaccine targeting four strains of seasonal flu, and the company projects it will turn a profit from the division in 2018. “The egg-based platform has been around for a long time,” Naylor says. “I don’t expect there will be an overnight transition.”