The United States is in the midst of a deadly flu season. The latest statistics from the Centers for Disease Control and Prevention report that 37 children have died so far this flu season, which began in October. The flu is currently widespread in 49 states, and doctors across the country continue to see more cases, more hospitalizations, and more deaths from influenza infections.

Over the past several weeks, deaths of Americans of all ages from the flu have made headlines. The family of 12-year-old Dylan Winnick, who died from the flu in Florida last week, said they were stunned by how quickly the virus took his life.

"No indications. No warnings. Just common cold. That's what's so scary about it," his stepfather Mike Medwin said.

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Two young mothers – Tandy Harmon of Gersham, Oregon, and Karlie Illg Slaven of Hendricks County, Indiana – also died of the flu last week. Their families said they were healthy until the sudden illness struck.

While flu is most dangerous for adults over the age of 65 and children under the age of 5, it can turn deadly for anyone.

The number of flu-related deaths varies widely from year to year, but even during a relatively mild flu season the illness claims thousands of lives. The CDC reports that over a three-decade period starting in the mid-1970s, the number of flu deaths in the U.S. ranged from a low of about 3,000 a year to as many as 49,000 in a bad year.

How does the flu lead to death?

While it is possible for the flu itself to cause death due to serious breathing problems and severe dehydration, according to Dr. Claire Bocchini, an infectious disease specialist at Texas Children's Hospital, it is more likely that a complication from the infection will be the cause of a flu-related fatality.

The most common complication from the flu that can lead to death is a bacterial infection of the lungs, or bacterial pneumonia.

"This happens because the flu virus injures the lungs and causes inflammation that then makes it easier for bacteria to invade the lungs and cause a very serious infection," Bocchini told CBS News. "The bacterial infection can make it hard for children to breathe, and their lungs struggle to get enough oxygen for their body."

Sepsis is another complication that can lead to death. It occurs when the body overreacts to an infection. Sepsis can affect multiple organ systems, sometimes causing organ failure and resulting in death.

Other rare complications from the flu that can be fatal include infection of the heart (or myocarditis) which can cause sudden death or heart failure, and infection of the brain (or encephalitis) which can lead to seizures and dangerous swelling of the brain.

Who is most at risk? Children under the age of 5, and especially those younger than 2, as well as people who are 65 and older are more likely to develop complications from flu. Also in the higher-risk group are pregnant women and people with chronic medical conditions such as lung disease, heart disease, diabetes, and neurologic conditions.

How can you protect yourself?

The best defense against the flu is to get the flu vaccine. The CDC recommends everyone age 6 months and older get a flu shot each year.

"The flu vaccine is a very safe vaccine that saves lives," Bocchini said. "Studies have shown that of the children who died from the flu in the U.S. last year, 85 percent were not immunized."

Although the flu vaccine doesn't guarantee that you won't get sick, doctors say it does reduce the chances, and if you do get sick it may be less severe.

If you develop flu-like symptoms, such as fever, body aches and fatigue, and you are at high risk for complications from the flu, it is important to see your doctor to ask if you should receive an antiviral medication such as Tamiflu (also available as generic oseltamivir), Relenza or Rapivab.

"There are antiviral medications that can be used to shorten the duration of illness as well as to help prevent complications from the flu," Bocchini said. "Antiviral medications should be started early to have their best chance of helping."

Take common-sense precautions to avoid exposure to the flu virus, such as washing your hands frequently and staying away from people who are sick. Stay home if you have flu-like symptoms until at least 24 hours after the fever is gone.

When to seek emergency medical attention

When the flu becomes severe, some people may need immediate medical attention to prevent further complications.

"Sometimes people will need to go to the emergency room to see a doctor right away due to the flu virus," Bocchini said. "It is very important to know the signs and symptoms that indicate when someone is very sick from the flu and needs help right away."

According to the CDC, emergency warning signs in children include:

Fast breathing or trouble breathing

Bluish skin color

Not drinking enough fluids

Not waking up or not interacting

Being so irritable that the child does not want to be held

Flu-like symptoms improve but then return with fever and worse cough

Fever with a rash

In adults, emergency warning signs from flu may present as:

Difficulty breathing or shortness of breath

Pain or pressure in the chest or abdomen

Sudden dizziness

Confusion

Severe or persistent vomiting

Flu-like symptoms that improve but then return with fever and worse cough

If you or your child have these symptoms, it is important to get medical treatment right away.