“There are only two things a child will share willingly: communicable diseases and its mother’s age.”
- Benjamin Spock, M.D., American Pediatrician and Author
“It’s important for children to be vaccinated so that they have the opportunity to become adults.”
- Brad McKay, M.D., Australian GP and Author
During the course of this pandemic, far fewer cases of COVID-19 have been reported in children than in adults. Child COVID-19 cases are, however, on the rise. The recent article in The Atlantic “We Are Turning COVID-19 Into a Young Person’s Disease” followed two days later by the headline in the Minneapolis StarTribune “School-age COVID Infections Soar” gave me reason to pause: What is happening? It therefore seemed like a good time to update my June 17, 2020 Germ Gem post “COVID-19 in Kids.”
Surge in childhood COVID-19. The American Academy of Pediatrics (AAP) and the Children’s Hospital Association reported that as of April 15, 2021, the total child COVID-19 cases in the U.S. since the beginning of the pandemic totaled 3,631,189. They also reported that the case numbers in children were on the rise across the country and that over the preceding two weeks, there was a 5% increase in the cumulated number of COVID-19 cases in kids. For the first time since the pandemic began, children’s cases topped 20% in the U.S.; their share of the COVID-19 burden has never been higher.
Despite this recent rise in children’s cases, there is good news. COVID-19 still appears to be less severe in children than in adults. The hospitalizations of children due to COVID-19 remain relatively uncommon (between 0.1%-1.9% of all child COVID-19 cases resulted in hospitalization), and mortality is still rare (in states reporting, 0.00%-0.03% of all child COVID-19 cases were fatal).
Immune system and disease severity. The reasons why COVID-19 is less severe in children than adults and why we are seeing an uptick in cases in kids still aren’t clear. But studies of the immune system of children carried out by Columbia University immunologist Donna Farber suggest that the answer to why kids are protected against severe disease lies in their robust innate immune system. Macrophages, neutrophils and NK cells make up the innate immune system. These cells stand ready to fight infectious agents like SARS-CoV-2, the cause of COVID-19, as soon as they encounter them. In contrast, the adaptive immune system comprised of B and T cells takes some time to gear up in response to pathogens by making antibodies to ward off the infection.
Failure of both the innate and adaptive immune systems to respond to this novel virus played a critical role in the devastation this pandemic initially caused especially among older adults in long-term care facilities. But now many adults have been vaccinated against SARS-Co-V-2. The vaccination of this population leaves a diminished number of vulnerable (non-immune) adults for this virus to infect. This could explain, in part, the apparent shift in cases from older adults to younger people, including children.
COVID-19 in children and adolescents. Most children with COVID-19 are asymptomatic or experience mild illness. Tragically, some children develop serious illness leading to hospitalization, use of mechanical ventilation, and death. According to a recent review of more than 2 million pediatric COVID-19 cases reported on April 9, 2021 in JAMA Network Open “Characteristics and Disease Severity of US Children and Adolescents Diagnosed with COVID-19,” nearly one-third of hospitalized pediatric patients experienced severe COVID-19. And severe disease was greater in those aged 2-11 years compared to older children aged 12-18 years.
Doctors across the country are also seeing a striking increase in the number of young people with the severe form of COVID-19 now called multisystem inflammatory syndrome in children (MIS-C). (When first recognized in early 2020, the syndrome was called pediatric inflammatory syndrome.) Symptoms of the syndrome include fever, rash, red eyes, trouble breathing, or gastrointestinal problems. As the disease progresses heart dysfunction, including cardiogenic shock, or cardiomyopathy (an enlarged heart) develops. To date more than 2,000 such cases have been reported to the Center for Disease Control and Prevention. The median age is 9, but infants to 20-year-olds have been afflicted. And surprisingly, young people with MIS-C aren’t any more likely to have underlying medical conditions than those who don’t develop this form of COVID-19. As researcher Dr. Adrianne Randolph put it, “It’s not like previously healthy kids are completely scot-free.”
In addition to the risk of developing MIS-C, about half of children with severe disease have an illness that is similar to that seen in adults and which predominantly affects the lungs. A risk factor for both forms of severe COVID-19 disease in children is ethnicity. More than two-thirds with either are Black or Hispanic. While some experts think the basis for this is rooted in the social determinants of health, it is not completely understood.
Protecting children against SARS-CoV-2. Currently, three vaccines have received emergency use authorization by the U.S. Food & Drug Administration (FDA) for adults: mRNA vaccines produced by Pfizer/BioNTech and Moderna, and a single-shot adenovirus-vectored vaccine from Johnson & Johnson. Pfizer’s vaccine also has been given approval for teens age 16 and up, and the company recently asked the FDA to extend its vaccine authorization for children as young as age 12. In addition, Pfizer now has clinical trials underway in children as young as six months old and Moderna is closely following suit in testing its vaccine in children.
Research shows that these new vaccines are remarkably effective and safe. The AAP urges teens 16 years-of- age and older to get a COVID-19 vaccine as soon as it is available to them. But children are not just little adults. We can’t assume a vaccine will have the same effect in a child as it does in an adult. Therefore, clinical trials need to be completed before COVID-19 vaccines become available for younger teens and children to ensure the vaccines are safe and effective for these age groups. Once this information is available, the AAP will make vaccine recommendations for younger children and adolescents.
Based on the experience so far with vaccination against COVID-19 in adults, we can anticipate children will be protected against severe and life-threatening forms of COVID-19, like MIS-C. Also, it is likely the vaccines will prevent asymptomatic infections and the transmission of SARS-CoV-2 to others thereby contributing to herd immunity that benefits everybody in the community.
In the meantime, what can we do to protect kids? In a recent article in The Atlantic, “The Urgency of Vaccinating Kids,” James Hamblin wrote: “It will be many months before kids can be vaccinated against SARS-CoV-2, so for people who would like to see schools resume normal operations, as soon as possible, the most important step is to get vaccinated themselves, and make sure their families and friends do the same.” This is sage advice. I suggest everyone follow it.
