Four-year-old dies after flu complications as U.S. pediatric cases rise

The death of a previously healthy four-year-old girl from influenza-related complications in Utah has underscored the unpredictable severity of this year’s flu season, which has already claimed the lives of at least 17 children in the United States, according to federal data. Health officials warn that pediatric cases can deteriorate rapidly, even in children with no underlying conditions.

As influenza activity remains high across much of the country, medical experts say the case highlights the importance of early warning signs, prompt medical evaluation, and preventive measures, including vaccination, particularly during seasons marked by strain mismatches and heavy circulation.

Ellie Rudd died on January 6 after contracting influenza alongside an adenovirus infection that progressed into pneumonia, sepsis, and ultimately multi-organ failure, her family said. She was four years old.

A sudden illness in a healthy child

Ellie will be buried wearing a light blue and white Princess Elsa costume from the animated film Frozen, one of her favorite movies. Her aunt made the outfit as a final gift.

Her mother, Sarah Rudd, described Ellie as energetic and robust, with no prior health problems. “She was probably my healthiest of all my kids,” Rudd said, adding that Ellie had no chronic conditions and rarely fell ill. “I have no idea why it hit her so hard.”

The flu entered the Rudd household in Ogden, Utah, on Christmas Day. Sarah Rudd, a mother of four, was the first to become ill, followed over the next week by the family’s three other children and her husband, Michael. While most family members experienced fevers and fatigue, Ellie initially appeared to recover after treatment with over-the-counter medication.

By early January, however, her condition worsened rapidly.

Rapid deterioration and hospitalization

On January 2, Ellie developed a distinctive barking cough and increasing breathing difficulty. She was taken to a local hospital, where she tested positive for influenza and adenovirus, a common virus that can cause respiratory infections in children. Her oxygen levels were low, prompting doctors to admit her for overnight observation and antiviral treatment.

Initial imaging showed no pneumonia, and clinicians expected a routine recovery. Within 24 hours, her condition sharply declined.

Ellie developed internal bleeding, pneumonia in one lung, and sepsis — a life-threatening inflammatory response to infection that can disrupt blood clotting and organ function. She was airlifted to Primary Children’s Hospital in Salt Lake City and placed on extracorporeal membrane oxygenation (ECMO), a form of life support used when the heart and lungs cannot function adequately on their own.

Doctors later identified blood clots in her heart. Surgery was deemed too risky, and blood-thinning medication offered limited benefit due to ongoing bleeding. On January 5, Ellie suffered a massive stroke. By the following day, doctors determined there was no brain activity on one side of her brain.

Her parents made the decision to withdraw life support.

A heavy flu season for children

Ellie’s death comes during a flu season that public health officials describe as unusually intense. According to the U.S. Centers for Disease Control and Prevention, outpatient visits for flu-like illness have reached their highest levels in nearly three decades.

At least 17 pediatric flu deaths have been reported so far this season, a number expected to rise as states complete reporting. Last season recorded 289 pediatric flu deaths, the highest total since national tracking began.

Experts say this season’s severity is partly driven by the emergence of a virus strain known as subclade K, which was not specifically included in this year’s flu vaccine formulation. Dr. Buddy Creech, a pediatric infectious disease specialist at Vanderbilt University, said such mismatches can reduce overall vaccine effectiveness, though vaccination still provides meaningful protection.

“Even with a mismatch, many people still generate antibodies that offer partial defense,” Creech said. He added that lower vaccination rates combined with viral evolution have contributed to widespread transmission.

Warning signs parents should watch for

Creech said Ellie’s case reflects a pattern pediatricians see each year: children who appear stable before suddenly becoming critically ill.

“Young children often look like they’re doing okay until they really aren’t,” he said. “The younger the child, the faster things can change.”

Physicians advise parents to monitor three key areas during respiratory illness: breathing, neurological responsiveness, and hydration.

Labored or rapid breathing, visible use of chest or neck muscles, lethargy, reduced interaction, and poor fluid intake are all warning signs that require urgent medical evaluation. Another indicator is whether a child improves after fever-reducing medication.

“If the fever comes down but the child still looks unwell, that’s a red flag,” Creech said.

A family’s message to others

Ellie’s siblings also fell ill during the same period. Her six-year-old sister developed pneumonia and bronchitis but has since recovered. The family has received support from relatives and friends, who organized a fundraiser to help cover medical and funeral expenses.

Sarah Rudd said the experience has fundamentally changed how the family thinks about illness prevention. The Rudds had not previously received annual flu vaccinations.

“Honestly, just get your flu shots,” she said. “Even if it doesn’t work perfectly, maybe it could help a little. We don’t really know — but it’s peace of mind.”

She said the family plans to pursue flu vaccination in future seasons.

“I’ve never been afraid of sickness before,” Rudd said. “Now I am.”