What’s the difference between a cold and the flu?

Each year in the U.S., millions of people contract infections during our cold and flu season (which typically runs from November to March). While there are some similarities between colds and the flu, there are also some important distinctions. Here are the key differences between these two infections.

1) Influenza can be diagnosed with a flu test

A specific test can be performed to diagnose influenza. A nasal sample is collected, and in less than 15 minutes, a rapid test can confirm whether you have the flu or not. On the other hand, there’s no test for the common cold. Colds are typically diagnosed based on symptoms and exam findings, and by excluding other causes of your symptoms, such as influenza.

2) Influenza often causes a fever

In adults, the common cold rarely causes a fever (which is defined as a temperature of 100.4 or higher). Influenza, however, often causes fevers that can reach up to 105 degrees, as the immune system raises the body’s temperature to make it more difficult for the influenza virus to replicate.

3) Influenza can cause gastrointestinal (gi) symptoms

While the common cold typically only causes symptoms in the respiratory tract, including nasal congestion, sore throats, laryngitis, and cough, influenza can infect, not only the respiratory tract, but also the GI tract, causing vomiting and/or diarrhea.

4) Influenza can lead to more serious complications

Influenza has the potential to cause more serious complications than the common cold, resulting in hundreds of thousands of hospitalizations and tens of thousands of deaths each year. Complications include pneumonia, dehydration, and inflammation of the heart (pericarditis), brain (encephalitis) and muscles (myositis). Influenza can also exacerbate underlying medical conditions, such as diabetes, asthma and heart disease.

5) Influenza is curable with medication

While there is symptomatic treatment available for patients with cold symptoms, there is no known cure for the common cold. Most common colds resolve on their own within 7-10 days.

For influenza, antiviral medications are available for patients. These antiviral medications help the infection resolve quicker and decrease the risk of secondary infections and other serious complications. This medication can also be taken to prevent influenza for at-risk patients with a known flu exposure.

6) Influenza is often preventable with a vaccine

Another difference between colds and influenza is that there is a vaccine available to prevent influenza infections. The flu shot provides protection against the four strains of the flu that are expected to arrive in the U.S. during our cold and flu season. Getting the flu shot decreases your risk of contracting influenza by up to 60%.