For the first time in 13 years, the flu is just about everywhere in the continental U.S., widespread in 49 states. And the rate of hospitalization has nearly doubled since last week.

The Centers for Disease Control is now reporting 20 pediatric deaths so far this season, compared to three at the same time last year.

This year's dominant flu strain, H3N2, is particularly dangerous for children and the elderly. Health officials won't know how well the flu shot worked until next month.

Recognize the emergency warning signs of flu

Children should go to the ER with any of these symptoms:
* 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

Get medical help right away for INFANTS when:
* Being unable to eat
* Has trouble breathing
* Has no tears when crying
* Significantly fewer wet diapers than normal

Adults should go to the ER with any of these symptoms:
* 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

The South is being hit especially hard. Alabama's governor has declared a public health emergency, and in Georgia, at Dekalb Medical, doctors saw more flu patients in the first week of 2018 than all of last month.

Dr. Daniel Jernigan runs the CDC's influenza division and says the epidemic is likely the worst in three years.

"The season is peaking right around now," said Dr. Jenigan. "It's happening in a lot of places at the same time, but there's still a lot more flu to go this year, maybe even 13 weeks more of flu activity."

Resources:

Knock out the flu - Washington State Department of Health