A Hudson Valley lab has developed the winning strain that pharmaceutical companies rely on to produce nearly half a billion doses of the influenza vaccine each year.

The lab is tucked away on the campus of the New York Medical College in Valhalla.

Virologist Doris Bucher says it only takes one of the many fertilized chicken eggs in the lab for her team of scientists to develop the strain.

“It starts here, and the eggs are incubated over there and that then gets expanded to 400 million doses around the world,” she says.

The process starts with injecting the eggs with four strains of the virus, including an old strain from 1934 and the swine flu.

"It's a Darwinian process, so the virus that grows the best wins and that's what we send out to the manufacturers," says Bucher.

The winning strain is then harvested, cloned and ultimately shipped to the Centers for Disease Control and Prevention in Atlanta, which gives the final go-ahead before the samples are mailed out to 20 manufacturers across the globe.

In the United States alone, more than 35,000 people die of the flu each year. The number would skyrocket if not for Dr. Bucher’s vaccines.