Peak flu season is October through May. The flu, also known as influenza, is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccine each year, according to the Centers for Disease Control and Prevention.

mug on bedside table - flu prevention and treatment

Flu Symptoms

Influenza can cause mild to severe illness and is different from a cold. The flu usually comes on suddenly and people often feel some or all of these symptoms:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults

It’s important to note that not everyone with flu will have a fever. The time from when a person is exposed and infected with flu to when symptoms begin is about 2 days, but can range from about 1 to 4 days.

Complications of flu can include bacterial pneumonia, ear infections, sinus infections, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.


If you show symptoms, see a medical provider as soon as possible. Your doctor can run a rapid flu test and if indicated, prescribe an antiviral medication proven to lessen the severity and duration of your illness. When taken promptly, antiviral drugs can reduce the time you are sick by 1 to 2 days and also prevent serious complications, such as pneumonia.

If you are experiencing flu-like symptoms, limit contact with other people and stay home for at least 24 hours after your fever is gone except for necessities and to get medical care. Make sure to cover coughs and sneezes with a tissue, throw the used tissue away, and wash your hands.

How Influenza Spreads

Most experts believe that flu viruses spread mainly by tiny droplets made when people with influenza cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby. A person might get flu by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes.

You may be able to spread the viral infection to someone else before you know you are sick, as well as while you are sick. Keep in mind these periods of contagiousness:

  • People with flu are most contagious in the first 3 to 4 days after their illness begins
  • Healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick
  • Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time

People at High Risk

Anyone can get influenza (even healthy people), and serious problems can happen at any age. However, some people are at high risk of developing serious flu-related complications if they get sick. This includes people 65 years and older, people of any age with certain chronic medical conditions (such as asthma, diabetes, or heart disease), pregnant women, and children younger than 5 years old.


The first and most important step in preventing flu is to get a influenza vaccine each year. The vaccine has been shown to reduce flu-related illnesses and the risk of serious complications that can result in hospitalization or even death. The CDC also recommends everyday preventive actions like staying away from people who are sick, covering coughs and sneezes, and frequent handwashing. This will help slow the spread of germs that cause respiratory (nose, throat, and lungs) illnesses, like the flu.

If you are feeling unwell, schedule a visit or walk-in to an Advanced Urgent Care & Occupational Medicine location near you. With locations across the Denver metro area, we’re open 7 days a week, 8 am to 8 pm.