Children are being hospitalized with COVID-19 in record numbers across the United States. 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.

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In a new feature, MNT explores the risks of SARS-CoV-2 spreading among children and looks at what strategies might prevent it. Image credit: FluxFactory/Getty Images

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

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) 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 symptoms 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, Medical News Today spoke with seven doctors and researchers who specialize in pediatrics and infectious diseases and have worked directly with children with COVID-19.

Stay informed with live updates on the current COVID-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.

The Delta variant of COVID-19 is more than two times 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,” Michael L. Chang, M.D., director of pediatric antimicrobial stewardship for McGovern Medical School and Children’s Memorial Hermann Hospital in Texas, told MNT. “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,” Kristin Moffitt, M.D., an infectious disease expert at Boston Children’s Hospital, MA, told MNT. “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,” she said. “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.”

“Overall, children are at lower risk for severe illness, hospitalization, and death due to COVID-19, but they are not at no risk.”

– Dr. Karen Ravin

“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,” noted 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,” Dr. Allison Ross Eckard, M.D., professor of pediatrics and medicine at the Medical University of South Carolina, told MNT.

“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,” Dr. Tina Q. Tan, M.D., medical director at Ann & Robert H. Lurie Children’s Hospital of Chicago, told MNT.

“[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,” Dr. Danielle Zerr, M.D., M.P.H., professor and division chief of pediatric infectious disease and adjunct professor of epidemiology, University of Washington, told MNT.

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.”

“In addition, some children are healthy but perhaps require an inhaler a couple [of] times per year, or some children’s families don’t even realize they are overweight. So, there is sometimes a misconception about a child’s risk. Therefore, it is very important for every family to discuss their child’s health with their primary care physicians to ensure that all children are appropriately protected.”

– Dr. Allison Eckard

“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,” Elizabeth Mack, M.D., M.S., medical director of pediatric critical care medicine at the Medical University of South Carolina, told MNT.

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.

The CDC currently recommends COVID-19 vaccines for everyone over the age of 12 years. This advice came after Pfizer announced that its vaccine is 100% effective in children aged 12–15, and Moderna reported that its vaccine is 100% effective in those aged 12–17.

Clinical trials for COVID-19 vaccines for children aged 11 years and younger are underway. Pfizer, for example, is currently carrying out a trial of its vaccine among children aged 6 months to 11 years.

“[V]accines have been shown to be highly effective at preventing severe disease, hospitalization, and death due to COVID-19 in adults and adolescents, and we anticipate the data will be similar for younger children,” said Dr. Ravin. “We hope that vaccines for children under 12 years of age will receive [emergency use authorization (EUA)] approval sometime this fall.”

Dr. Tan echoed these thoughts, saying, “It is expected that data from these trials will be available by mid-to-late fall, and if the data demonstrate that the vaccines are immunogenic and safe, an [EUA] for use in children 5–11 years may be available by the end of 2021 and for children 2–4 years, by the beginning of 2022.”

“While vaccine effectiveness against any infection from Delta is reduced in adults, the effectiveness in adults against serious illness and hospitalization remains very high,” said Dr. Chang.

“There is no reason to think that the vaccines in children will perform any differently than what we are observing in adults at this time.”

– Michael L. Chang, M.D.

“I strongly encourage families to vaccinate anyone in their family who is eligible, including their children. These vaccines have now been given to millions of children and are incredibly safe and effective,” said Dr. Eckard.

“At our hospital, all children who were admitted with severe COVID-19 (and those who have sadly died) were unvaccinated [as of August 24, 2021].”

Although medical professionals are optimistic about COVID-19 vaccines for those younger than 12 years, the American Academy of Pediatrics (AAP) cautions against the off-label use of COVID-19 vaccines in children this age. The AAP makes this warning because the doses of adult vaccines are much higher than the doses that researchers are trialing on young children, and safety and efficacy data for this age group are yet to be seen.

Dr. Tan outlined eight steps that parents, caregivers, schools, and children can take to curb the spread of SARS-CoV-2 as children return to school:

  1. “Anyone who is eligible to receive a COVID-19 vaccine should be vaccinated — this includes parents, household members, teachers, staff, etc.
  2. Universal mask-wearing for all students, teachers, and staff regardless of vaccination status.
  3. Practicing social/physical distancing with desks in the classrooms at least 3 feet apart.
  4. Good hand hygiene.
  5. Cohorting students, teachers, and staff into smaller groups or pods.
  6. Discouraging large gatherings of students, teachers, and staff — e.g., staggering pickup and drop off times, increasing the number of lunch hours to prevent large number of people from being in the cafeteria at the same time, and having students eat at their desks.
  7. Good ventilation in classrooms or using outdoor space if possible.
  8. Have protocols in place if someone is symptomatic or tests positive for SARS-CoV-2.”

Dr. Chang added that parents should not send their kids to schools if they have infectious symptoms, whether or not these are due to COVID-19.

“Just because a child doesn’t have COVID, a runny nose, congestion, or cough could be due to another communicable infection which can complicate the picture for everyone. Parents with symptomatic kids should discuss the symptoms with their child’s healthcare provider before sending the child to school,” he said.

“Really, the most important and effective action would be to decrease the rate of spread of [SARS-CoV-2] in the community through the same measures that worked previously, but now also to include vaccinating all those who are eligible,” he added.

“By decreasing the overall rates of COVID in the community, the likelihood of a teacher, school staff, or child getting [SARS-CoV-2] goes down. That also reduces the likelihood of an infected teacher, school staff, or child going to school while contagious. If rates of new infections are low in your community, then parents can feel more confident that their children can attend in-person school safely,” he concluded.

As tests for COVID-19 are now widely accessible in the U.S., doctors recommend widespread testing for school staff and students — whether in vaccinated individuals or in those with or without symptoms.

“I think it’s also important to encourage testing for any possible symptoms — even in vaccinated individuals,” said Dr. Moffitt. “COVID-19 tests are much easier to get now than they were this time last year, and symptoms of infection may be milder in vaccinated individuals — so what seems like just a sore throat or “common cold” may actually be [SARS-CoV-2] infection and deserves a test.”

“Testing programs (testing asymptomatic people) may be available in some schools — these programs can be helpful in identifying [people with the infection] early, so [the virus doesn’t have the chance to transmit] to as many people,” added Dr. Zerr.

Preventing the spread of SARS-CoV-2 among children may also depend on out-of-school transmission.

“What students and families do outside of school matters,” explained Dr. Eckard. “Sleepovers, parties, travel, and other high risk activities outside of school increase the risk of a student getting infected and bringing the infection back to the school [for it possibly to transmit to] others — an even higher chance now with the very contagious Delta variant.”

“We all must work together if we want to achieve what hopefully is our common goal — to keep kids in the classroom,” she concluded.

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