Can the Flu Turn Into Pneumonia?

The flu is a common respiratory infection that most people will have at some point in their lifetime. Many recover from the flu in about a week. But some people go on to have serious complications from the flu — like pneumonia.

Pneumonia is an infection where part of one or both lungs fill with pus or fluid. This can happen as your immune system tries to fight off an infection. The flu doesn’t always turn into pneumonia. But there are some risk factors that can make it more likely.

Let’s take a closer look at the signs you may be developing pneumonia and when to get help. 

Can the flu turn into pneumonia?

The short answer is yes. The flu can result in pneumonia in two different ways: direct infection (viral pneumonia) and secondary infection.

The influenza virus can directly infect the cells in the lungs. In fact, the flu is the most common cause of pneumonia in adults. Flu and pneumonia are a dangerous combination. Together, they’re a leading cause of death in the U.S. every year.

In addition to directly causing pneumonia, the influenza virus can weaken the immune system. A weak immune system isn’t able to fight off bacteria that make their way into the lungs. If the bacteria aren’t cleared by the immune system, they can flourish and cause a lung infection, in addition to the flu. The flu can turn into a “secondary bacterial infection” of the lungs (secondary pneumonia). 

What are the differences between the flu and pneumonia?

The flu and pneumonia are both respiratory illnesses that can cause cough and affect your breathing. But they’re different conditions with different causes. They also have different symptoms and treatments. 

Let’s take a closer look at the flu and pneumonia, as well as their differences.

Can you have pneumonia and the flu at the same time?

Yes, it’s possible to have pneumonia and the flu at the same time. Pneumonia can be caused by a variety of germs. So, it’s possible to be infected with the flu and another germ that causes pneumonia — like COVID-19 — together.

This may be more likely to happen when the immune system isn’t strong, causing more than one virus or bacteria to invade. That’s why it’s a good idea to get medical attention when you have symptoms of the flu or pneumonia. A healthcare professional can run some tests to see exactly what infection(s) are causing your symptoms.

What makes it more likely to get pneumonia after the flu?

Most of the time, the flu doesn’t turn into pneumonia. But certain risk factors can make it more likely, such as:

• Age: Children ages 5 years and younger and adults older than 65 years are at higher risk of getting pneumonia from the flu. 

• Chronic conditions: Your risk is increased if you have health problems such as asthma, chronic obstructive pulmonary disease (COPD), diabetes, and heart disease.

• Smoking: Smoking can worsen flu and make it easier to get pneumonia after having the flu.

• Severe flu infection: If you end up in the hospital because of the flu, your risk of getting pneumonia goes up. 

How can you prevent the flu from turning into pneumonia?

Taking care of your health can lower the chance of getting sick and keep you healthier during flu season. Here are a few simple steps that can make a big difference in preventing flu complications, like pneumonia:

• Get vaccinated. The flu shot lowers the risk of getting the flu. It also reduces the chances of complications, including pneumonia.

• Practice good hygiene. Regularly wash your hands with soap and water, especially after coughing or sneezing. Using hand sanitizer is also helpful in killing germs.

• Avoid close contact. Try to avoid close contact with people who are sick. If you’re not feeling well, keep your distance as well to stop the spread of flu.

• Stay healthy. Eat nutritious food, exercise, and make sure to get enough sleep. A strong immune system can fight off infections better. 

• Avoid smoking. If you smoke, quitting is beneficial for your overall lung health. This can help prevent health problems.

• Get care early. If you experience flu symptoms, talk with a healthcare professional. Taking antiviral medication within 2 days of flu symptoms appearing can be helpful. They can reduce how bad the flu gets and lower your risk of complications.

How can you tell if the flu is turning into pneumonia?

If you have the flu and start to feel worse rather than better over the next 7 to 10 days, you might be developing a complication like pneumonia. Some signs include:

• More trouble breathing

• Chest pain

• Chest congestion

• Fever that won’t go away

• Cough with mucus

If you start to have these symptoms, make an appointment for medical attention right away. A healthcare professional may order an X-ray or blood tests to see if pneumonia is causing your symptoms.

Quiz: Do I have pneumonia?

When should you see a healthcare professional for flu symptoms?

Most people can recover from the flu at home. But sometimes you need to get medical attention for your flu symptoms. This is especially important for young kids, older people, or those with underlying medical conditions who are at risk of serious complications. 

Signs you need to see a healthcare professional are:

• Symptoms that aren’t improving or are getting worse

• Fever that doesn’t get better

• Trouble breathing

• Cough that won’t go away

• Chest pain 

• Lack of appetite

• Feeling faint or dizzy

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Written by:

Bernadette Anderson, MD, MPH

A native of Saginaw, Michigan, Dr. Bernadette earned an undergraduate degree in psychology from the University of Michigan, Ann Arbor. She completed a master's degree in public health at the University of California, Berkeley, and a doctorate of medicine from the Medical College of Ohio.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. A pulmonologist and hospitalist, she practiced and taught clinical medicine at hospitals in London for a decade before entering a career in health education and technology.

Reviewed by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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