As flu season approaches in the United States, health experts are sounding the alarm over a rare but serious complication that can strike even healthy children. Known as acute necrotizing encephalopathy (ANE), the condition causes dangerous brain swelling and can be fatal in nearly one in four cases. While flu infections are common and usually resolve without hospital care, doctors are urging parents to stay vigilant after reports showed dozens of children across the US developed this life-threatening illness during recent flu seasons.
What is rare flu ‘acute necrotizing encephalopathy’
Acute necrotizing encephalopathy is an extremely rare complication that arises when the immune system overreacts to a viral infection, most often the flu. This immune response disrupts the blood-brain barrier, leading to severe inflammation, brain tissue damage, and swelling. “It’s one of those extremely rare but extremely serious complications that happens predominantly in children,” explained Dr. Nicholas Dragolea to Daily Mail. “When it strikes, it tends to progress rapidly, and outcomes can be devastating if not caught in time.”
Warning signs parents should look out for
Doctors stress that parents should not ignore sudden changes in a child’s flu symptoms. Early red flags include fainting spells, seizures, breathing difficulties, and sudden trouble with movement. “Most children will recover from flu with rest and fluids,” Dr. Dragolea said, “but if you notice neurological symptoms, don’t wait — seek emergency medical care immediately.”
Who is most at risk?
A recent review published in JAMA identified 41 cases of ANE in children across the last two flu seasons. Alarmingly, three-quarters of these children were considered completely healthy before infection, and most were around five years old. “What makes ANE especially concerning is that it’s not just children with underlying conditions,” noted Dr. Dragolea. “Even healthy kids can develop it, which is why awareness is crucial for both doctors and parents.”
How rare is the condition?
Though highly concerning, experts emphasize that ANE remains rare. Among millions of flu infections each year in the US, only a small fraction progress to this stage. In the JAMA study, 11 of the 41 children affected — or 27 percent — died, while the rest required prolonged hospital stays of up to three weeks. The CDC has also confirmed cases in past flu seasons, reporting that among 68 children who died of the flu last year, nine had encephalopathy and four had the acute form.
Vaccination remains a key defense
The JAMA review found that just 16 percent of children affected by ANE had received the flu vaccine, despite CDC recommendations that all children six months and older be vaccinated annually. “Vaccination doesn’t completely eliminate the risk, but it dramatically reduces the likelihood of severe flu complications,” said Dr. Fatimah Dawood, a medical officer at the CDC’s influenza division. Experts warn that low vaccination coverage could leave more children vulnerable to dangerous outcomes this season.
Could the pandemic be a factor?
Doctors also suggest that pandemic lockdowns, which reduced children’s exposure to everyday microbes, may have played a role in rising cases of rare complications. “We know the immune system develops with exposure,” said Dr. Dragolea. “The disruption caused by COVID-19 might have had unintended effects on how some children respond to flu infections.”
The bottom line for parents
Flu is common and usually mild, but doctors emphasize that rare complications like ANE should not be overlooked. Parents are urged to vaccinate their children, monitor symptoms closely, and act quickly if unusual neurological signs emerge. “These cases remind us that while flu is familiar, it can sometimes be unpredictable and devastating,” Dr. Dragolea warned. “Preparedness and awareness are the best tools we have to save lives.”
