The Science of the Flu: How It Makes You Miserable

The flu is simple, right? You get it from germs, it feels terrible and then you get better.

Turns out there’s a bit more going on.

Every year, millions of people will get sick from the flu—but many don’t know how it works or spreads or what they can do to prevent it.

Chanda Newsome, Director of Infection Control at Wayne UNC Health Care, explains the science behind the flu and how you can stay healthy this flu season.

How It Works in Your Body

Influenza, also known as the flu, is a highly contagious respiratory infection that originates in animals such as birds and pigs. “Investigating the flu and the different types of flu, particularly Influenza A, includes a focus on flu in animals,” Newsome says, particularly in the Southern Hemisphere, where there is a high concentration of these animals in close proximity to people. (Read more about how flu predictions are made.)

Although most flu transmission happens from person to person, new strains can emerge in animals and jump to humans if they’re in close contact with infected animals. Transmission between people can happen from inhaling droplets that someone coughs or sneezes out or by picking up viruses from contaminated surfaces.

The flu virus targets the respiratory system, entering through the nose and mouth.  “The virus binds to respiratory cells and begins to replicate itself,” says Newsome, “turning those cells into a copy machine for the flu.”

Not only does the flu virus copy itself in order to grow and spread, it can also change.   Different molecular combinations of the flu, such as H1N1 and H3N2, are what make the flu different from other viruses.  The continuous evolution of the flu virus can make it difficult to predict which form of the virus will be circulating.

Epidemics happen when an infectious disease spreads rapidly, and a pandemic is a global disease outbreak. Flu pandemics happen when a new flu virus arises—most recently in 2009 with H1N1, or “swine flu”—which means humans have little to no immunity against it.

The best way to protect yourself and those around you against the flu is to get an annual flu shot.  It is important to get vaccinated as early in the flu season as possible, before you come into contact with the virus.  Flu vaccines are now being offered at provider offices as well as pharmacies.