It’s the public health symphony of the season: clearing your airway so you can carry on. But it is also a warning about where all that congestion can lead without care.

Pneumonia is an infection of the lungs that can cause mild to severe illness in people of all ages.

Emergency room doctors see more people coming into the emergency rooms during flu and cold season with the most common symptoms.

"People with pneumonia, they typically have fever, chills, cough, and shortness of breath, " said Dr. Robert Bernauer, an emergency room physician.

As the season progresses, so do complications from pneumonia, when your lungs become inflamed and fill up with fluid, creating symptoms, such as a cough, fever, chills, and trouble breathing.

When you have pneumonia, oxygen may have trouble reaching your blood which is just another reason why it’s important to get to a doctor.

"When you have the flu, it affects your body and allows for a superinfection of bacterial pneumonia, " said Dr. Bernauer.

Those most at risk are the very young and very old, which is why health officials always stress flu vaccinations for those populations because of the high number of fatalities in those different age groups every year.

Antibiotics are prescribed if pneumonia is confirmed.

The viruses and bacteria that are commonly found in a child's nose or throat can infect the lungs if they are inhaled.

They may also spread via airborne droplets from a cough or sneeze.

"The best way to prevent pneumonia is washing your hands, stop smoking, and make sure you're up to date on all of your vaccinations,” said Dr. Bernauer.

You are more likely to become ill with pneumonia if you smoke or have underlying medical conditions.

And it can develop after an illness such as a cold, not just the flu.

With treatment, most cases of pneumonia will improve within one to three weeks. Older or debilitated patients may need longer treatment.

Pneumonia is the leading infectious cause of death in children younger than five years old worldwide.