In March 2020, then 14-year-old Kitty McFarland was living an active lifestyle. She spent her time dancing ballet, paddle boarding, running, and playing netball. That spring, Kitty contracted COVID-19. She developed a cough and fever, and at one point her mother recalls finding her frighteningly unresponsive.
Though her symptoms eased at first, Kitty’s health sharply declined a month later. Severe illness left her bedridden for eight months. She missed large portions of school, while doctors struggled to provide answers. Kitty describes living with Long COVID as being “on a roller coaster forever,” with constant, unpredictable ups and downs.
Kitty’s experience is far from unique. Recent research published in Lancet Infectious Diseases shows that children and teens are especially vulnerable. The study found that people under 21 are twice as likely to develop Long COVID after a second infection compared to their first. Many had assumed later infections would be milder, but the findings challenge that belief.
Higher Risk of Long COVID after Reinfection
The study evaluated data from nearly 500,000 people under age 21. It was part of the National Institutes of Health’s RECOVER Initiative, a program designed to study Long COVID. Researchers compiled electronic health records from 40 children’s hospitals across the U.S., analyzing cases from January 1, 2022, to October 13, 2023. Most cases were Omicron infections, though researchers believe the findings apply to newer variants like Nimbus and Stratus.
Over six months, the study found that 1,884 people per million developed Long COVID after two infections. This was twice the rate of those with only one infection, measured at 904 per million. The findings challenge earlier assumptions that later infections are less severe.
Researchers also flagged widespread misdiagnosis. Tens of thousands of children without a COVID-19 diagnosis were treated for symptoms matching Long COVID, such as breathing problems and abdominal discomfort. This suggests the study’s estimates may understate the true impact. Even with conservative data, the CDC reports that about 1.3% of U.S. children under 18—around 1 million young people—have experienced Long COVID symptoms.
Severe Health Risks Linked to Reinfections
The study also measured specific health risks linked to multiple infections. Overall, children and young adults were 3.6 times more likely to develop myocarditis after a second infection compared to those infected only once. Myocarditis, a dangerous heart inflammation, can be fatal and is a known complication of Long COVID and other illnesses.
Participants were also 2.8 times more likely to experience problems with taste and smell. They were 2.3 times more likely to form blood clots. In addition, young people with two infections were nearly twice as likely to develop cardiovascular disease or kidney injury.
The data showed some patterns. Those who developed Long COVID after a second infection were more likely to have pre-existing chronic conditions. Still, researchers noted that many affected youth had no prior health conditions at all.
Vaccination status played a significant role. About three-quarters of the study participants had not received a COVID-19 vaccine. Unvaccinated youth faced higher risks of the most severe symptoms, including myocarditis. While the study was not designed to evaluate vaccine effectiveness, its findings suggest that vaccines reduce the chance of dangerous outcomes.
Despite this evidence, U.S. Health Secretary Robert F. Kennedy has advised against COVID-19 vaccination for healthy children. The study’s authors argue that their data strongly contradicts his position.
Conclusion
Long COVID continues to pose serious risks for children and teens. Reinfections raise the chances of severe health problems, including heart and kidney issues. The latest research shows many young people remain vulnerable, especially those unvaccinated.
Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.
Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.


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