With China reporting 8 deaths and 24 infections from a strain of the H7N9 bird flu, people around the world are beginning to wonder about the possibility of another pandemic.

“Sadly, I think the question is really more when, rather than if it will happen,” said Oklahoma Medical Research Foundation scientist Linda Thompson, Ph.D. “This strain of bird flu probably won’t become a pandemic, because it doesn’t seem to spread easily between people. But the likelihood that we’ll see another major outbreak in the future is real.”

Thompson spent years studying the influenza vaccine in lupus patients and was part of a group that submitted antibodies to the U.S. Centers for Disease Control during the H1N1 swine flu outbreak in 2009. While many remember the hype surrounding the swine flu, few know the outcome: even after scientists at the CDC developed a vaccine, about 10,000 Americans died.

Influenza viruses spread easily, infect rapidly and are prone to mutation, Thompson said.

“The virus you encountered last year has gone around the world, person to person, and in order to survive, it has changed,” she said. “Those changes are why we’re encouraged to get flu shots every year.”

And because pigs and birds both can carry multiple strains of influenza at the same time, it opens up the possibility of reassortment—a mixing of genetic material that can create a new form of the virus.

“They’re like a melting pot for the flu,” Thompson said. “The virus that comes out might be harmless and hard to spread, or it might be incredibly easy to transmit and deadly.”

The Chinese government killed more than 20,000 birds in the live-poultry trading zone and announced they are already working on an H7N9 vaccine. The Atlanta-based CDC said state health departments are also getting ready in case the virus begins to spread and makes its way to the U.S.

The flu shot is comprised of protein from three strains of flu virus. The main component is hemagglutinin (the “H” in the name of the virus). Hemagglutinin is the protein on the flu virus that binds to human cells. The immune system examines the proteins and creates antibodies that can prevent the virus from binding to human cells and infecting them. Thompson said influenza researchers are looking for vaccines that create antibodies to target the parts of flu viruses that don’t change each year in the hopes of creating a “universal” shot that can fight all variations of the virus.

“Influenza is always changing, but researchers around the world are monitoring the situation and working to keep us ahead of the curve,” she said.