Cold and Flu

Every fall and winter, that familiar feeling seems to creep up at least once: a slight tickle in your throat, congestion in your nose, or an annoying cough that just won’t quit. Usually, that means you’re sick with something—probably a cold or the flu.

It’s not surprising if you’re not sure what you’ve caught, considering how often we often lump cold and flu into the same general category. Yes, they’re both caused by viruses and tend to trigger similar symptoms, but they’re also very different illnesses.

Giacomo Gambineri

You’ve probably endured many colds in your lifetime, as this viral infection affects millions of people every year in the US, according to the Centers for Disease Control and Prevention (CDC).

Common colds are caused by “one of many respiratory viruses, such as parainfluenza, rhinovirus, and coronaviruses,” Dawn Nolt, MD, MPH, a professor specializing in pediatric infectious diseases at Oregon Health & Science University, tells SELF. Rhinoviruses are by far the most common to cause colds, but human coronaviruses are also a likely culprit (though that does not include the coronaviruses that cause COVID-19, SARS, or MERS).¹

The flu, which is short for influenza, is also a common infectious disease; it affects an average of 8% of people in the US every year, per the CDC. There are only three viruses that can cause the flu in people: influenza A, B, or C. While influenza C usually leads to mild cases of the flu, both influenza A and B are the viruses responsible for causing the “flu season” we prepare for every fall and winter, per the CDC.

Once a person has a cold or the flu, they are contagious and can spread it to other people, mainly via respiratory droplets that spread through coughing, sneezing, or talking. It’s also possible for a person to catch a cold or flu by touching a contaminated surface, like a germy doorknob, and then touching their eyes, nose, or mouth with unwashed hands.

Colds tend to be mild, and you can usually recover at home without needing any treatment. The flu, on the other hand, can lead to potentially serious complications in high-risk people, including infants, pregnant people, immunocompromised people, and older adults.

The term “stomach flu” is a bit confusing, however, because it isn’t actually caused by influenza, a virus that only affects your respiratory system, according to the Mayo Clinic. “Stomach flu is a common name for gastroenteritis, which is an infection of the stomach and intestines,” Omer Eugene Beaird, MD, an assistant clinical professor of infectious diseases at the UCLA David Geffen School of Medicine, tells SELF. Stomach flu symptoms tend to affect the digestive tract more prominently, often setting off cramping, diarrhea, vomiting, and nausea, in addition to muscle aches and a low-grade fever. “Most cases of gastroenteritis are caused by norovirus and enteroviruses,” Dr. Beaird says.

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