Every year, millions of Americans feel the symptoms of influenza creep up. First a sore throat, then a stuffy nose. Within a day or two, the flu virus is on full-attack mode, causing fever, headaches, nausea, chills, muscle soreness, body aches, and fatigue. While it may initially feel like a cold, it quickly becomes worse, leaving most people bedridden, some hospitalized, and unfortunately for some, dead. The flu has eluded all efforts to create a universal, long-lasting vaccine for decades. But pretty soon we may have one, according to doctors at the Icahn School of Medicine at Mount Sinai Health System in New York City.

Science has always been one step behind the flu virus; it’s constantly mutating. Quick mutations typically occur in animals like pigs, where bird and human strains of the virus combine DNA within an infected cell, creating a new strain. But it’s the slower mutations, which are called antigenic drift, that form the basis of the flu vaccine. As companies prepare a vaccine based on three to four strains, however, the virus’ genetic makeup continues to “drift,” changing just enough that the vaccine isn’t always effective — this has led to only 33 percent effectiveness in this year’s flu vaccine.

“What we have a vaccine for is producing antibodies that are somewhat different than what the flu is. That happens,” Mount Sinai Health System’s CEO and President Kenneth Davis told CNBC, speaking about the current vaccine. A universal vaccine would be able to target all current and future strains of the virus. Researchers from Mount Sinai believe they can develop a vaccine that protects people for a decade or longer within the next two years. “The ideal vaccine is directed at the stable part of the virus that doesn’t change from year-to-year. That’s very hard to do.”

Speaking to ABC News, Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center in Nashville, said to think of the structure of the flu virus as a sphere with “a bunch of lollipops on stems sticking out of it.” While the candy part of the lollipop changes from year to year, the stick remains the same. It’s that part of the virus Davis considers the stable part, which can be targeted for vaccine development.

The Mount Sinai team, which is working with an outside company to develop the vaccine, expects to start clinical trials on later on this year. “A universal vaccine is the Holy Grail and the prospects of what this could do for medicine is staggering,” Schaffner told ABC, admitting that the effectiveness is something to be concerned about. Nevertheless, the Mount Sinai team is hopeful. “We really hope it will be effective on humans,” Dr. Peter Palese, chair of the Department of Microbiology at the Icahn School of Medicine, told ABC. “But of course the jury is still out.”