Does Your Child Have Long COVID? Researchers Uncover Key Symptoms

Long COVID affects young children differently, with unique symptom patterns revealed in a new study.

Long COVID, a condition where symptoms continue long after the initial infection, can affect people of all ages — even the youngest among us. But in infants, toddlers, and preschoolers, these lingering symptoms often look very different from what we see in adults and older children.

In a new study conducted by researchers at Mass General Brigham, in collaboration with the federally funded RECOVER initiative, researchers examined how long COVID shows up in young children and uncovered some important differences.

They found that infants and toddlers, younger than two years old, were most likely to experience trouble sleeping, fussiness, poor appetite, a stuffy nose, and a persistent cough. Preschool-aged children, between three and five years old, were more likely to struggle with a dry cough and feel unusually tired during the day.

The findings were published in the journal JAMA Pediatrics.

“This study is important because it shows that long COVID symptoms in young children are different from those in older children and adults,” said co-first author Tanayott (Tony) Thaweethai, PhD, associate director of Biostatistics Research and Engagement at Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham healthcare system. Thaweethai is also an assistant professor at Harvard Medical School. “Children with these symptoms often had worse overall health, lower quality of life, and delays in development.”

Study Design and Methodology

The new study is the latest publication from National Institutes of Health (NIH)-funded Researching COVID to Enhance Recovery (RECOVER) initiative, which seeks to explore the effects of long COVID across all ages. This paper builds on a previously published study that examined long COVID symptoms in school-aged children (6 to 11 years old) and teenagers (12 to 17 years old). In this new study, Thaweethai and fellow RECOVER researchers focused on younger age groups, infants and toddlers and preschool-age children.

The study included 472 infants/toddlers and 539 preschool-aged children, some of whom had previously had COVID and some who had not. Children were enrolled between March 2022 and July 2024 from over 30 U.S. health care and community settings.

Researchers looked at a variety of caregiver-reported symptoms lasting at least 90 days after COVID infection for both age groups—41 symptoms in the infant/toddler group and 75 symptoms among preschool-aged children. They compared children who had not been previously infected to those with a history of COVID to see which symptoms persisted. Among children who had been previously infected, 40 of 278 infants/toddlers (14%) and 61 of 399 preschool-aged children (15%) were classified as likely having long COVID.

Distinct Symptom Patterns and Future Directions

“We found a distinguishable pattern for both age groups of young children, including symptoms that are different than what we see in older children and adults,” said co-senior author Andrea Foulkes, ScD, director of Biostatistics at MGH, professor in the Department of Medicine at Harvard Medical School, and professor in the Department of Biostatistics at the Harvard T.H. Chan School of Public Health. “The tools from this study can be used in future studies to better understand long COVID in young children and develop ways to care for them.”

The authors note that the symptoms reported in the paper have been identified for research purposes, not for making a clinical diagnosis, and that caregivers should talk to a child’s clinician if they are concerned about symptoms of long COVID. They also note that their study relies on survey data, which can be affected by recall bias and may be difficult to report accurately for children too young to verbalize their symptoms and where antibody confirmation of infection may be incomplete.

Reference: “Characterizing Long COVID Symptoms During Early Childhood” by Rachel S. Gross, Tanayott Thaweethai, Amy L. Salisbury, et al., 27 May 2025, JAMA Pediatrics.
DOI: 10.1001/jamapediatrics.2025.1066

Disclosures: Snowden served on a Pfizer COVID-19 advisory board; Milner served on a scientific advisory board for Blueprint Medicine

Funding: This study was funded in part by the National Institutes of Health (OT2HL161841, OT2HL161847, OT2HL156812, R01 HL162373).

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