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Study finds risk factors for severe COVID-19 cases in children

UT Southwestern researchers show living in the Southern U.S., having preexisting conditions linked to more serious illness

Doctor’s hands in protection gloves putting COVID-19 test swab into kid’s mouth in hospital.
A UT Southwestern study looked at severe health outcomes among children who tested positive for COVID-19 between January 2020 and January 2022. (Photo credit: Getty Images)

DALLAS – Nov. 21, 2023 – Children who had preexisting health problems or who lived in the Southern United States had a higher risk for severe health outcomes from acute COVID-19 infections, according to researchers at UT Southwestern Medical Center. The results, reported in the journal Hospital Pediatrics that is published by the American Academy of Pediatrics, also showed the importance of vaccinations in reducing the severity of illness for those who became infected.

Christoph Lehmann, M.D.
Christoph Lehmann, M.D., Professor of Pediatrics and in the Lyda Hill Department of Bioinformatics, is Director of the Clinical Informatics Center and a member of the Peter O'Donnell Jr. School of Public Health at UT Southwestern.

“While receiving the COVID-19 vaccines did not mean that our little patients would not get sick from the virus, vaccines did protect them from more severe outcomes such as death and intensive care admissions. Protecting your children by immunizing them is a good thing, especially if your child has a preexisting condition, such as heart disease or asthma,” said one of the study’s authors, Christoph Lehmann, M.D., Professor of Pediatrics and in the Lyda Hill Department of Bioinformatics, Director of the Clinical Informatics Center, and a member of the Peter O’Donnell Jr. School of Public Health at UT Southwestern.

The national study analyzed records from 165,437 children age 18 and younger who tested positive for COVID-19 between January 2020 and January 2022. About 1.8% were hospitalized without complication, 1.8% were admitted to intensive care or needed intensive respiratory support, and 31 children died.

The researchers found that children in the Southern United States were more than three times as likely to have more severe complications compared with other areas of the country.

“It matters where you live,” Dr. Lehmann noted. “While we do not know what causes children in the South to have worse outcomes, our findings call for an exploration of possible causes – such as weather and climate, immunization rates, public health or government messaging, mandates, and closures.”

The study also found that among children under age 5, those younger than 2 years old were at the highest risk for severe outcomes. This finding contradicts initial anecdotal observations suggesting that infants were not as prone to severe disease with COVID-19 as they were from other respiratory viruses such as respiratory syncytial virus (RSV).

“While this wasn’t surprising to us – smaller airways are disproportionately affected by respiratory illness – it does mean that we have to be more vigilant when the little ones acquire COVID-19,” Dr. Lehmann added.

Finally, the study found that those with multiple chronic medical conditions, such as heart disease and lung disease, were more than twice as likely to have severe complications following COVID-19 infection, and the more chronic conditions they had, the higher the risk.

Other UTSW researchers who contributed to this study include lead author Robert W. Turer, M.D., Assistant Professor of Emergency Medicine; first author and medical student Milan Ho, B.S.; Trish M. Perl, M.D., M.Sc., Professor of Internal Medicine; Zachary M. Most, M.D., M.Sc., Assistant Professor of Pediatrics; Bhaskar Thakur, Ph.D., Assistant Professor of Family and Community Medicine, Emergency Medicine, and Physical Medicine & Rehabilitation and a member of the O’Donnell School of Public Health; John J. Hanna, M.D., Assistant Instructor of Internal Medicine; Marlon I. Diaz, B.S., Sameh Saleh, M.D., Madison Pickering, M.S., and Richard J. Medford, M.D., all with the Clinical Informatics Center; medical student Julia A. Casazza, B.S.; and Postdoctoral Research Fellow Alexander P. Radunsky, Ph.D.

Dr. Lehmann holds the Willis C. Maddrey, M.D. Distinguished Professorship in Clinical Science. Dr. Perl, a member of the O’Donnell School of Public Health, holds the H. Ben and Isabelle T. Decherd Chair in Internal Medicine in Honor of Henry M. Winans, Sr., M.D.

This study was funded by the National Center for Advancing Translational Sciences of the National Institutes of Health (UL1 TR003163).

About UT Southwestern Medical Center 

UT Southwestern, one of the nation’s premier academic medical centers, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty members have received six Nobel Prizes and include 26 members of the National Academy of Sciences, 20 members of the National Academy of Medicine, and 13 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 3,100 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in more than 80 specialties to more than 120,000 hospitalized patients, more than 360,000 emergency room cases, and oversee nearly 5 million outpatient visits a year.