How Bad Can the Flu Be?



Fact checked by Nick Blackmer

Key Takeaways

  • Even young, healthy individuals can become critically ill from the flu.

  • The flu vaccine may not prevent 100% of flu cases, but it will decrease your likelihood of developing severe illness from the influenza virus.

  • Patients and families whose lives have been direly impacted by the flu are spreading awareness of the importance of getting a yearly flu vaccine.

In March of 2013, then-33-year-old Allison Miller started feeling run down on a Friday evening. The following day, she woke up feeling worse, with a bad cough and sore throat, so she went to urgent care, where providers took a chest X-ray, gave her a prescription cough syrup, and instructed her to return if she continued to get worse.

Over the next 24 hours, Allison declined quickly.

“I had a ton of back pain. I am fairly sure I blacked out a couple of times. I had never felt so sick in my life,” she told Verywell. Allison called a friend for help, who called 911 upon seeing her condition.

Allison does not recall the most acute phase of her illness, and much of that time was recounted to her by others. She was admitted to the intensive care unit (ICU) with pneumonia and sepsis, experienced organ failure, and was placed on an extreme form of life support called extracorporeal membrane oxygenation (ECMO) for five days. Circulation complications from ECMO cost Allison her left leg.

Allison didn’t have a mystery illness—she had influenza. Had she known about the potential risk of complications, she says she would’ve gotten a flu shot, despite not having any risk factors for severe disease.

“I didn’t realize that the [CDC] advice had changed,” she said, explaining she thought only the elderly, healthcare workers, and the immunocompromised individual needed a flu shot. “I didn’t see a doctor regularly enough to have it suggested to me, so it didn’t occur to me as something I needed to do. A flu shot is not a guarantee I wouldn’t have gotten sick, but it probably wouldn’t have been as severe as it ended up being.”

Allison’s story highlights an important fact: Even young, healthy individuals can become critically ill from the flu. Influenza sends thousands of people to the hospital each year. That’s why annual flu shots are so important, and why Allison now advocates for them as a part of the nonprofit organization Families Fighting Flu.

Related: How Deadly Is the Flu?

Why Flu Complications Can Happen

Mild-to-moderate cases of the flu will resolve on their own within a few weeks. However, in some cases, the immune system overreacts to the flu, causing widespread inflammation throughout the body.

The immune response spirals out of control, and the same substances that should fight the flu begin to damage healthy body tissues that are not infected by the virus. For example, severe flu can lead to myocarditis (inflammation of the heart), encephalitis (inflammation of the brain), and multiorgan failure, particularly of the kidneys and lungs. Sepsis (a life-threatening, whole-body response to infection), is another potential complication of the flu.

Signs Your Illness Is Serious

The most common symptoms of the flu are cough, fever, chills, body aches, sore throat, fatigue, nausea and vomiting. To avoid spreading the influenza virus, avoid leaving your home unless absolutely necessary until you have been fever-free (without fever-reducing medications like Tylenol) for at least 24 hours.

Adults should seek medical care if they begin to develop any of the following:

  • Fever or cough improves for a time, then begins to worsen

  • Shortness of breath or difficulty breathing

  • Persistent pain or pressure in the chest or abdomen

  • A change in mental status such as confusion or lethargy

  • Seizures

  • Signs of dehydration, such as no urination

  • Severe muscle pain, weakness, unsteadiness, or dizziness

  • Pre-existing chronic health conditions begin to worsen

In addition to the above, parents or guardians should seek medical care if they notice any of the following in their child:

  • Fast breathing

  • Ribs pulling inward with each breath (also called retractions)

  • Bluish lips or nails (a sign of low oxygen)

  • No wet diapers or urination for eight hours, dry mouth, crying but producing no tears

  • A fever in a child less than 12 weeks old, or a fever above 104 in a child of any age

Related: Recognizing Early Flu Symptoms in Children

Trouble breathing was the first sign something was wrong in 5-year-old Caroline Miller, who was swimming three times a week and taking gymnastic classes when she became sick with the flu in December 2012. She didn’t exhibit the usual flu symptoms of fever, chills, and muscle aches, but did have a minor cough and congestion. Her asthma medications were not enough to get her breathing under control.

At the advice of their pediatrician, Caroline’s mother, Jennifer Miller, took her daughter to the hospital. Caroline’s subsequent diagnosis of influenza A and pneumonia in both lungs required supplemental oxygen, and an eventual airlift to a hospital with a dedicated pediatric unit for more specialized management.

“The thought of your child going on a helicopter is terrifying, but even more heartbreaking, we couldn’t go with her. You’re signing over responsibility of your child to perfect strangers,” Jennifer, who also works with Families Fighting Flu, told Verywell. She said her family had been planning on getting the flu shot, but hadn’t made time for it yet. “When you see a loved one, particularly a child, clinging to life because you didn’t take advantage of a life-saving intervention, it changes the trajectory of all things.”

After two weeks in a medically induced coma on an oscillatory ventilator, Caroline began to recover. She required rehab with physical and occupational therapists, and is a healthy 16-year-old field hockey player today.

Almost Everyone Needs a Flu Shot

Since 2010, the Centers for Disease Control and Prevention (CDC) has recommended that individuals aged 6 months and older receive a yearly flu vaccine, including busy, active, healthy people.

The only people who should not get a flu shot are individuals who have had a severe, life-threatening allergic reaction (such as anaphylaxis) to any of the flu vaccine’s ingredients or a previous flu shot. Anyone with a history of Guillain-Barré syndrome (a severe, paralyzing illness) should speak with their provider before getting a flu shot.

Even if you don’t think you personally need a flu shot, remember: It’s protecting people around you who are high-risk.

“From newborns up to the age of 5 or 6, the immune system is immature, so we worry about children getting complications from influenza. In older adults, the immune system is starting to slow down, so it’s just not as strong as it used to be,” Gregg Sylvester, MD, MPH, a pediatrician and the Chief Health Officer of CSL Seqirus, a leader in influenza vaccine science, told Verywell. “We worry about the two ends of the spectrum, but the recommendation applies to everyone. Anybody is at risk of getting complications from the flu. It’s crucial to understand that the flu is not just a bad cold.”

If you’re hesitant to get the immunization because of needles, you may be eligible for a nasal flu vaccine called FluMist Quadrivalent. Unlike other flu vaccines, which use a weakened or deadened form of the influenza virus, the nasal vaccine uses a live flu virus. That means it’s not safe for certain groups of people, including (but not limited to) anyone aged 50 or older or people with weakened immune systems.


FluMist Quadrivalent is less widely available than conventional flu shots, so you will need to search for a local pharmacy or physician's office that offers it.

“Both nasal flu vaccines and traditional flu shots offer relatively similar protection against the season’s circulating strains of influenza when administered in the populations and age groups for which they are licensed,” Sylvester said. “Choosing one or the other may be a personal preference or convenience. Regardless of vaccine preference, everyone needs to do their part in protecting themselves and loved ones by receiving an annual influenza vaccine.”

Related: You Might Be Able to Give Yourself a FluMist Vaccine at Home Next Year

Many quick-care clinics and pharmacies offer same-day vaccines, so you don’t need to make an appointment with your doctor’s office days or weeks in advance.

“Go ahead and get the vaccine,” Allison said. “There’s not a downside to protecting yourself against the permanent effects of the flu.”

What This Means For You

Getting a flu vaccine is a quick and simple way to protect yourself and those around you from the potentially dire consequences of the flu. Medicare, Medicaid, and all Affordable Care Act (ACA)-compliant health insurance policies cover flu vaccines, so there will be no out-of-pocket cost to you. If you do not have health insurance, you may be able to receive low-cost vaccines from your local health department. Children who do not have health insurance or whose insurance does not cover all vaccines qualify for no-cost vaccines through the federal Vaccines for Children (VFC) program.

Read the original article on Verywell Health.