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 the heart and lung health of 1,475 adults about 21 months after getting COVID-19. The study used a wearable wrist device (called a Fitbit) to take measurements of heart and lung health. Researchers found that adults with more Long COVID symptoms showed signs of lower physical fitness. These adults had higher resting heart rate, lower heart rate variability (a measure of heart stress), took fewer daily steps, and spent less time being active. People with lower physical fitness and activity levels also reported having more symptoms, like feeling very tired (fatigue), dizziness, and feeling worse after activity. These findings show that Long COVID may be linked to lasting problems with physical fitness and daily activity almost 2 years after getting COVID-19. This study is important because it points out how wearable wrist devices may help researchers and doctors track how Long COVID affects the body over time.

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 link between Long COVID and school difficulties in school-age children (ages 6 –11 years old) and adolescents (ages 12–17 years old). Researchers studied 1,976 children across the US, including 406 school-age children and 1,570 adolescents, both with and without Long COVID. Based on information about school performance reported by their caregivers, children with Long COVID were about twice as likely to have worsened grades after the COVID-19 pandemic compared to those without Long COVID. About 1 in 5 school-age children and nearly 3 in 10 adolescents with Long COVID had worse grades. Those who experienced Long COVID were also more likely to have trouble paying attention in school and had a harder time having fun with their friends. Children and adolescents with Long COVID were also more likely to have an Individualized Education Program (IEP) or be in the process of getting one. An IEP is a special plan that schools use to help students with special needs. These findings show that Long COVID can make school harder for children and adolescents. The study also highlights the continued need for schools to offer support to students with Long COVID.

In this RECOVER study, researchers looked at how people with Long COVID, caregivers, and community members were included as partners in research. These partners are called Representatives. Researchers studied how Representatives joined RECOVER, how they took part in meetings and decisions, and how well this process worked. Researchers used surveys to learn about Representatives’ roles and experiences. The study found that most Representatives understood their roles and responsibilities. About 3 out of 4 said they felt comfortable sharing their ideas and taking part in decisions. The study found challenges, including words used in meetings that were hard to understand and not having enough time to share opinions. It also highlighted a need for clearer communication and more participation from rural and tribal communities. In addition to sharing their lived experiences, RECOVER Representatives work with researchers to help decide how studies should be conducted and how study results should be shared. Representatives' input keeps the research focused on what matters most to people affected by Long COVID. Representatives' input also makes it easier for everyone to understand what RECOVER researchers have done and what they've learned about Long COVID. This study is important because it shows that working with Representatives can help build trust between researchers and the community. Researchers also recommend ways that future studies can successfully partner with patients and community members.

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. 

In this study, RECOVER researchers looked at whether getting COVID-19 during pregnancy affects a baby’s brain development. Researchers followed over 1,000 families across the US and compared babies up to 18 months in age who were exposed to COVID-19 during their mother’s pregnancy to those who were not. Researchers tracked the babies’ development at 12 and 18 months, looking at how they moved, talked, solved problems, and interacted with others. Researchers found that babies exposed to COVID-19, mostly during the Omicron wave of the pandemic, scored just as well as babies who were not exposed. Researchers also found no big differences in babies’ social skills or risk of delays in their brain development during their first 18 months of life. These findings are important because they can reassure mothers who get COVID-19 during pregnancy about the brain development of their child. However, doctors should continue to check children who were exposed to COVID-19 during their mother’s pregnancy as they grow to ensure their development stays on track.