Doctors say why children hospitalized with COVID-19 in record numbers

Children are being hospitalized with COVID-19 in record numbers across the United States. Cases have risen “exponentially” to record highs, pediatricians report.

As most children are not old enough to get vaccinated, hospitalizations could further increase as schools reopen. Doctors and epidemiologists are thus calling for the use of safety precautions, such as masks and ventilation, during class.

The rise in cases of COVID-19 among children in the U.S. is primarily linked to the Delta variant. Cases are rising especially quickly in communities with low rates of COVID-19 vaccinations.

Although the Centers for Disease Control and Prevention (CDC)Trusted Source recommend universal indoor masking and physical distancing in schools, mask-wearing is optional in North Dakota and Ohio.

Rapidly increasing infection rates among children and teachers have forced many schools in the U.S. to halt in-person learning and turn to hybrid models of education. This comes despite 175 pediatric disease experts agreeing earlier this year that elementary schools could open full-time for in-person instruction.

Although children generally have milder COVID-19 symptomsTrusted Source than adults, the fact that few studies have investigated how the disease affects children means that many questions remain unanswered. For example, why are so many children being hospitalized with COVID-19? Which children are most at risk? And what can parents and authorities do so that children can return to school safely?

To answer these questions and more, seven doctors and researchers who specialize in pediatrics and infectious diseases have have shared insights from their work directly with children who contracted COVID-19.

The Delta variant of COVID-19 is more than two timesTrusted Source as contagious as previous variants. Alongside school reopenings, this may partially explain the increase in pediatric hospitalizations due to COVID-19.

“The Delta variant that is circulating widely is more contagious, and children are getting infected more often than previously during the pandemic,” said Michael L. Chang, M.D., director of pediatric antimicrobial stewardship for McGovern Medical School and Children’s Memorial Hermann Hospital in Texas. “Also, across the country, mitigation measures such as masks, reduced occupancy indoors, physical distancing, etc., all ended around the same time.”

“Now, you have a more contagious variant with fewer mitigation measures in place. With the rising number of cases, unfortunately, you will see more hospitalizations. As an example, if 2% of children need hospitalization, then it’s a big difference between 2% of 10,000 cases vs. 2% of 100,000 cases,” he added.

Another reason for rising COVID-19 hospitalizations among children may be that those under the age of 12 years cannot get the vaccination yet.

“Vaccines remain effective at preventing severe illness, hospitalization, and death from [SARS-CoV-2] infection, even Delta strain infection,” said Kristin Moffitt, M.D., an infectious disease expert at Boston Children’s Hospital, MA. “This is consistent with reports that the overwhelming majority of hospitalizations and deaths during the recent surge are occurring in unvaccinated individuals.”

“Since children under 12 aren’t yet able to be vaccinated, and many adolescents and young adults remain unvaccinated relative to older individuals, this age group is making up a bigger proportion of those at risk for severe illness based on their unvaccinated status,” she added.

Dr. Karen Ravin, M.D., chief of infectious diseases at Nemours Children’s Hospital in Delaware, agreed.

“Children under 12 years of age make up a substantial proportion of the unvaccinated population in the U.S., so they are the population at highest risk,” said Ravin. “Early in the pandemic, schools were closed, and children had a lower risk of exposure in the community. Contrast this to now, schools are open for in-person instruction […] so children are at greater risk for being exposed, becoming infected, and, unfortunately, being hospitalized.”

“Early in the pandemic, those over 65 accounted for more severe disease and hospitalization. Now that this age group has a higher percentage of vaccinated persons, the disease burden will be seen in the younger, unvaccinated population,” said Dr. Adriana Cadilla, an infectious diseases pediatric specialist at Nemours Children’s Hospital in Orlando, FL.

“[In Florida,] there has been over a four-fold increase in child [SARS-CoV-2] infections in the past month,” Dr. Cadilla added.

Although the number of COVID-19 cases among children is increasing more quickly now than at any other time in the pandemic, it is unclear whether the Delta variant of SARS-CoV-2 is more severe for children than previous variants.

“We don’t know if the Delta variant causes more severe disease for kids than previous variants, but it’s definitely more contagious,” said Dr. Chang.

Due to low testing and hospital admissions among children from previous variants, the data to compare the outcome of COVID-19 strains are sparse. As schools reopen, however, and safety precautions such as mask-wearing wane, more children are becoming infected with SARS-CoV-2 at the same time, leading to higher numbers of children developing severe COVID-19.

“There are some indications to suggest that COVID-19 from the Delta variant is more severe in children than with earlier strains,” said Dr. Allison Ross Eckard, M.D., professor of pediatrics and medicine at the Medical University of South Carolina.

“We are seeing a greater number of children, particularly unvaccinated adolescents, with more severe COVID-19 resulting in respiratory failure that is requiring intubation and sometimes ECMO (heart-lung bypass machine), ARDS (a very serious lung condition that develops as a result of the inflammation associated with COVID-19), and other COVID-related problems — all complications we more commonly see in adults,” she continued.

“It may be that the increased number of hospitalizations among children is a result of both of these factors — more cases combined with a higher chance of severe disease. More data is needed to determine the exact reason(s) behind what we are seeing,” she added.

The CDC says that children with underlying medical conditions, such as congenital heart disease or genetic, neurologic, or metabolic conditions, could have an increased risk of severe outcomes from COVID-19.

The CDC states that this higher risk also applies to children with obesity, diabetes, asthma, chronic lung disease, sickle cell disease, or immunosuppression.

“Children who are at higher risk of adverse outcomes from COVID-19 are those under 1 year of age, those with underlying conditions, and those with immunocompromising conditions, including those on immunocompromising medications,” said Dr. Tina Q. Tan, M.D., medical director at Ann & Robert H. Lurie Children’s Hospital of Chicago.

“[Other] children may also develop more severe disease, resulting in the need for hospitalization, but at a lower rate than those with underlying or immunocompromising conditions,” she added.

“Anecdotally, most of our hospitalized patients with COVID-19 are unvaccinated teenagers. Many of these teens are quite ill, and their only risk factors are obesity and/or asthma,” said Dr. Danielle Zerr, M.D., M.P.H., professor and division chief of pediatric infectious disease and adjunct professor of epidemiology, University of Washington.

Dr. Chang echoed these statements, saying that teenagers with a body mass index of 25 or above and infants under the age of 1 year have a higher risk of hospitalization.

“Many families think their children are healthy and, therefore, not at risk of severe COVID-19,” said Dr. Eckard. “While that is true statistically, we cannot always predict which children will develop severe disease, and children [without underlying conditions] sometimes do develop severe disease.”

“We are still learning what causes some children to develop more severe COVID-19 than others, but it is important to know that perfectly healthy children can develop severe COVID-19,” said Elizabeth Mack, M.D., M.S., director of pediatric critical care medicine at the Medical University of South Carolina.

Dr. Mack also noted that the risk of death from severe COVID-19 remains a possibility even for children without underlying conditions.

Race, ethnicity, and socioeconomic conditions may also play a role in adverse outcomes from COVID-19 among children. Dr. Cadilla noted, “Hospitalization rates are higher among Hispanic [and] Latino children and non-Hispanic Black children, mirroring adult data.”

While more data are necessary to confirm why this is the case among children, among adults, research highlights deep-seated inequities that put these populations at higher risk.

For example, Hispanic, Latinx, and non-Hispanic Black populations are more likely to be uninsured, working in jobs that do not offer remote working, and living in conditions that make it difficult to practice physical distancing and self-isolation. These populations also have higher rates of underlying health conditions, such as diabetes and obesity.

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