Research Summaries

Researchers wanted to know why some children get sicker than others when they get COVID-19. Different versions (variants) of SARS-CoV-2, the virus that causes COVID-19, can affect children differently. A child’s age, sex, race, or ethnicity (demographic factors) may also play a role in determining which COVID symptoms they experience—and how burdensome (severe) those symptoms become.

Researchers reviewed electronic health record (EHR) data from a large group of children (ages 0–25) who visited Children’s Hospital Los Angeles between 2020 and 2024 and tested positive for SARS-CoV-2. Next, researchers analyzed biosamples to identify which viral variant was responsible for causing a child's COVID-19. Researchers then compared COVID-19 severity between different viral variants and demographic factors.

Researchers found that COVID-19 caused by the Omicron variant was more likely to be associated with moderate or severe COVID-19 in children compared to COVID-19 caused by earlier variants, like Delta or Epsilon. This finding contrasts with studies in adults that generally found that Omicron infections were milder. The authors also noted that Long COVID cases did not appear to cluster around specific variant periods, suggesting that children’s risk of developing Long COVID may not be tied to a particular variant in the same way it may be in adults.

In terms of demographic factors, researchers found that children who were male had an increased likelihood of experiencing moderate or severe COVID-19 compared with females. Younger children (0–5 years) showed an increased likelihood of experiencing moderate or severe COVID-19 compared to older children. Researchers also found that COVID-19 severity can differ across racial and ethnic groups. For example, Hispanic/Latino and White children included in the study were less likely to develop severe COVID-19 as their age increased, while the data showed Asian children showed a slight increase in severe illness at older ages.

These findings suggest that age, race and ethnicity, and viral variants may interact in complex ways to influence how sick a child becomes with COVID-19. Understanding how viral variants interact with children’s demographic characteristics could inform how health providers care for children who may be at higher risk of experiencing severe COVID-19 or Long COVID.

In this RECOVER study, researchers wanted to learn how Long COVID affects the everyday functioning of children, teenagers, and young adults. Researchers examined the electronic health records (EHRs) of 686 children and young adults under 21 years old, including 651 who got COVID-19 and received care in 21 hospitals across the U.S. They compared young people who had Long COVID to those who had COVID-19 but did not have Long COVID. They found that young people with Long COVID were more likely to have trouble in school, need extra school support, and develop new or worsening behavioral or mental health issues like anxiety and depression. This study is important because it highlights that doctors should ask about school, daily activities, and emotional well-being when caring for young people who’ve had COVID-19. Long COVID can affect these parts of everyday life and require extra support.

RECOVER researchers looked at whether taking selective serotonin reuptake inhibitors (SSRIs) and serotonin–norepinephrine reuptake inhibitors (SNRIs) around the time of having COVID-19 was linked to Long COVID in children, teenagers, and young adults. SSRIs and SNRIs are medicines used to manage mood and mental health symptoms. Researchers reviewed the electronic health records (EHRs) of more than 110,000 young people (ages 5 to 20) who had neuropsychiatric conditions and COVID-19. Neuropsychiatric conditions are disorders that affect how the brain works and how a person thinks, feels, or acts. Researchers compared young people who took SSRIs or SNRIs to those who did not. The study found that taking SSRIs or SNRIs was not linked to a higher or lower chance of receiving a Long COVID diagnosis. However, young people taking these medicines were less likely to experience fever, chills, or hair loss after having COVID-19. Young people taking these medicines were more likely to experience extreme tiredness (fatigue), memory problems, and postural orthostatic tachycardia syndrome (POTS, which is a condition that can cause a fast heart rate when standing up). These findings are important because they suggest that children, teens, and young adults taking SSRIs or SNRIs may have different long-term symptoms after getting COVID-19, which doctors should monitor.

In this RECOVER study, researchers looked at whether children who received steroids soon after getting COVID-19 were less likely to develop Long COVID. Steroids are medicines that help with inflammation (swelling and irritation) in the body. Researchers reviewed the electronic health records (EHRs) of more than 850,000 children under 19 years old who had a positive COVID-19 test, a COVID-19 diagnosis, or received antiviral medicines for COVID-19 between March 2020 and April 2024. Researchers then compared children who received steroids within 12 days of getting COVID-19 to those who did not. They also looked at children who were hospitalized and children who were treated at home. Researchers found that steroid use was not linked to a lower risk of developing Long COVID. However, children who were not hospitalized with COVID-19 and took steroids had a lower risk of experiencing stomach problems associated with Long COVID. This study is important because it shows that early steroid use was not linked to a lower risk of Long COVID in children. More research is needed to understand which treatments may help prevent long-term symptoms from developing in children who get COVID-19.

In this RECOVER study, researchers looked at the relationship between a young person’s weight and their health after getting COVID-19. Researchers reviewed the electronic health records (EHRs) of over 139,000 children and young adults, ages 5–20 years, across the US. They grouped participants based on their body mass index (BMI). BMI is a number that helps show whether someone is at a healthy weight, is overweight, has obesity, or has severe obesity based on their height and weight. The researchers checked if any new health problems were added to participants’ EHRs between 1 and 6 months after getting COVID-19. The study found that children and young adults with severe obesity were much more likely to develop health problems after getting COVID-19. These included problems related to the heart, like high blood pressure, and stomach problems, like diarrhea and heartburn. The researchers also checked whether participants had mental health issues after getting COVID-19. Those results were less clear and may have been due to other factors. This study is important because it shows that doctors should be thinking about the weight of children and young adults affected by COVID-19. If a child is overweight or has obesity and gets COVID-19, doctors should monitor their heart and stomach health to make sure they receive the care they need. 

This RECOVER study looked at whether COVID-19 was linked to a higher risk for dyslipidemia (unusual levels of fats or cholesterol in the blood) or a high body mass index (BMI) in children and young adults. BMI is a number that helps show if someone's weight is in the healthy range for their height. A higher BMI can be a sign that a person may be overweight or have obesity. Researchers looked at the electronic health records (EHRs) of over one million children and young adults, from birth to age 21, across 25 different children’s hospitals in the US. Researchers followed the health of children and young adults for up to 6 months after they got COVID-19 for the first time and compared them to a group of children and young adults who did not get COVID-19. Researchers found that children and young adults who got COVID-19 were about 24% more likely to develop dyslipidemia and 15% more likely to develop a high or unhealthy BMI than those who never had COVID-19. These findings are important because they show that COVID-19 may be linked to a higher risk of health problems related to blood fats and weight. These findings also highlight the need for closer follow-up of children and young adults during their recovery from COVID-19.  

In this RECOVER study, researchers wanted to understand the connection between Long COVID and chronic kidney disease (CKD) in adults who had COVID-19. CKD is long-term, permanent damage to the kidneys. Researchers looked at the electronic health records (EHRs) of more than 2 million adults across 59 health systems in the US to see if people with CKD were more likely to develop Long COVID. The study found that, compared to people without CKD, those who had even mild cases of CKD were more likely to get Long COVID after COVID-19. Researchers also found that, compared to adults who did not get Long COVID, those who developed Long COVID and had healthy kidneys before getting COVID-19 were more likely to develop new CKD or have worsened kidney function within a year. These findings show how Long COVID and kidney disease can affect each other and highlight how important it is for doctors to monitor people’s kidney health after they get COVID-19.

This RECOVER study looked at whether people with Human Immunodeficiency Virus (HIV) are more likely to get Long COVID after having COVID-19. HIV is a virus that attacks the body’s immune system. Researchers used electronic health records (EHRs) from 2 nationwide research networks of people ages 21 and older who had COVID-19. They divided them into 2 groups: people with HIV and people without HIV. Researchers used 2 methods to find people in the groups who might have Long COVID. One used a computer system that looked for Long COVID symptoms in medical records. The other looked for official diagnosis codes that doctors enter when they think someone has Long COVID. They found that people with HIV may have a slightly higher risk of being diagnosed with Long COVID when looking for Long COVID symptoms in medical records. However, they found that there was no clear link between having HIV and receiving the official diagnosis code for Long COVID. This suggests that Long COVID may be missed in people with long-term health problems like HIV.