Repeat COVID dramatically increases risk of long COVID in children
A large-scale study shows that adolescents and children who contract COVID-19 a second time face Long COVID twice as often as peers with a single infection. These findings shatter the myth that repeat infections are harmless for young bodies.
If you still think children get COVID "easily" without consequences, and that reinfection only strengthens immunity — it's time to look at the numbers. A new study published in The Lancet Infectious Diseases shatters this comforting misconception: children and adolescents who contract COVID-19 a second time are diagnosed with long COVID twice as often as after their first encounter with the virus. Not by a few percent. Twice.
No "immune training" — just accumulating damage
Researchers analyzed electronic medical records of 465,717 children and adolescents under 21 from 40 U.S. children's hospitals. All were part of the RECOVER database — a massive initiative by the National Institutes of Health launched specifically to study the long-term effects of COVID. The observation period ran from January 1, 2022, to October 13, 2023, the era of Omicron dominance.
Of the entire cohort, 407,300 children were infected once, and 58,417 caught the virus again. Median age was just over eight years. Boys and girls were evenly split.
The results are as follows. After the first infection, 904 children per million received a diagnosis of PASC (post-acute sequelae of SARS-CoV-2 infection, the official name for long COVID) within six months. After reinfection, that number rose to 1,884 per million. The relative risk increased by 2.08 times.
Researchers did not rely on subjective complaints — they used a strict criterion: the presence of diagnostic code U09.9 entered by a physician in the medical record. This means a pediatrician or specialist considered the patient's condition serious enough to officially document it. Since doctors often fail to code many symptoms, the 1,884 cases per million are almost certainly just the tip of the iceberg. Senior author Yong Chen from the University of Pennsylvania confirms: "This diagnostic code captures only a fraction of long COVID cases."
What exactly breaks down in a child's body
Reinfection doesn't just increase the chance of a formal diagnosis. It systematically hits different body systems, and the list of secondary outcomes reads like a catalog of what no parent would wish on their child.
Myocarditis — inflammation of the heart muscle — jumps 3.6 times. This is not statistical noise: RR 3.60 with a confidence interval of 1.46–8.86 means the association is real, even accounting for the rarity of the event.
Taste and smell changes occur 2.83 times more often. Thrombophlebitis and thromboembolism — 2.28 times. Cardiac diseases — 1.96 times. Acute kidney injury — 1.90 times. Next on the list are arrhythmias, fluid and electrolyte imbalances, abnormal liver enzyme levels, chest and muscle pain.
A separate category is neurological and cognitive consequences. Headaches increase 1.46 times, cognitive impairment 1.32 times, and the risk of POTS (postural orthostatic tachycardia syndrome, where the heart races upon standing and vision darkens) and other forms of autonomic dysfunction — 1.35 times. For a teenager, this means not "laziness" or "growing out of it," but an objective inability to study normally or play sports.
David Liebowitz, professor of medicine at Northwestern University and co-author of the study, puts it bluntly: "The risk appears cumulative. Each subsequent infection is not neutralized by previous immunity — it adds to the long-term burden."
Three-quarters unvaccinated and parental fatigue
Among the children in the study, 77.7% had not received a single vaccine dose. Only 4.4% had received three or more doses. This is partly because vaccines for younger age groups were delayed — mass availability only opened up by mid-2021. But by 2022–2023, when data collection was underway, vaccination campaigns were in full swing. Parents simply stopped vaccinating their children.
The reasons are a toxic mix of pandemic fatigue, the myth that Omicron is harmless for children, and a general erosion of trust in public health. Liebowitz directly names the culprits: "Pandemic fatigue, perception of Omicron as a mild illness for children, delayed vaccine availability for the youngest."
An important nuance: the increased risk of long COVID with reinfection persisted across all subgroups — both vaccinated and unvaccinated, and among those who had a mild first infection. Vaccination does not provide 100% protection against long COVID in breakthrough infections, but studies show it reduces the risk by about half — simply by preventing infection in the first place.
Who loses and who gets a chance
The most obvious loser is children's public health. About 1.3% of Americans under 18, or roughly one million children, already have a history of long COVID by the most conservative CDC estimates. Chen and colleagues' study shows this number will grow with each new wave, even if acute COVID is as mild as a common cold.
School systems also lose — they are just beginning to recover from mass absences and learning gaps. A child with cognitive impairment, chronic fatigue, and POTS is a student who physically cannot endure a school day. No amount of "catching up" works here.
The pharmaceutical market receives an alarming signal to expand. Pediatric long COVID is not just "fatigue" — it is a multisystem disease affecting the heart, kidneys, blood vessels, and nervous system. It will require not just one drug, but entire management protocols for these patients. Post-COVID syndrome clinics for children are a growing niche, but currently exist only in major medical centers.
Insurance companies must prepare for pediatric long COVID to become a chronic expense item. Myocarditis requires a cardiologist, thrombosis a hematologist, cognitive impairment a neuropsychologist. And all this stretches over years.
The only unconditional beneficiary is public health systems, which will take these data as a call to action. Ravi Jhaveri, head of pediatric infectious diseases at Lurie Children's Hospital in Chicago and co-author of the study, puts it without diplomacy: "This is one of the strongest arguments for vaccination that I give to patients, families, and doctors. More vaccines — fewer infections — less long COVID."
What happens next
No vague predictions. Three concrete vectors are already visible.
First — long-term monitoring. The RECOVER team will continue to track the cohort to understand how symptoms evolve three, five, ten years after reinfection. Senior author Yong Chen confirms: "Long-term monitoring is necessary to shape clinical care and public health strategies."
Second — new viral variants. The study covered the Omicron era through October 2023. Since then, new subvariants have emerged, and data on their ability to cause long COVID in children are not yet available. But there is no reason to think the risk has decreased: the pathophysiology of post-COVID conditions is tied not to a specific strain, but to systemic immune dysfunction.
Third — vaccination policy. In 2025, the CDC shifted to a "shared decision-making" model for childhood vaccination, softening previous universal recommendations. The American Academy of Pediatrics still insists on universal vaccination for children aged 6–23 months and older children with risk factors. After the RECOVER data publication, pressure to return to universal recommendations will intensify.
The final formula that the study drives into public consciousness is extremely simple: each reinfection is an additional roll of the dice, with a child's health at stake months and years after the runny nose is gone. A previous infection does not protect against long COVID. It increases its likelihood. And this knowledge must change the behavior of parents, pediatricians, and health officials — right now, not when the next wave has already hit schools.
— Editorial Team
