News & Views: COVID-19 and Kids — What Do We Know?

As time passes and cases of COVID-19 increase, we are learning more about SARS-CoV-2 infections in children and young adults.

Infection

While children are less likely to suffer from severe illness when infected with SARS-CoV-2, they can still be infected, and a small percentage will suffer complications and death (described below).

As of Sept. 10, 2020, more than half a million cases of COVID-19 have been diagnosed in children. This represents about 10% of all cases. To see updates, visit the state-level data reports being offered by the American Academy of Pediatrics and the Children’s Hospital Association.

Data are still being compiled related to the percent of asymptomatic infections in children, but is likely to be between 16% and 45%, according to the Centers for Disease Control and Prevention (CDC).

Transmission

While evidence suggests that children are less likely to experience symptoms of infection, it is also becoming clear that they can be infected and have high quantities of virus, particularly in their nasopharynx or oropharynx:

• Heald-Sargent and colleagues evaluated viral load in nasopharyngeal swabs from 145 patients with mild to moderate illness within one week of symptom onset. Patients were split into three groups by age (< 5 years, 5-17 years, and 18-65 years), and the results indicated that children younger than 5 had more detectable virus and that viral load did not correlate with symptoms.
• Yonker and colleagues evaluated 192 patients up to 22 years of age who presented to urgent care or were hospitalized with suspected SARS-CoV-2 infection. Viral loads, measured in nasopharyngeal or oropharyngeal samples, did not correlate with the presence of symptoms and were highest during days 0-2 of symptoms. The Yonker study also found that of 11 children who were tested based on an exposure rather than symptoms, three were positive for SARS-CoV-2.

Hospitalization

Based on a 14-state hospitalization network, almost 600 children less than 18 years of age were hospitalized with COVID-19 between March 1 and July 25, 2020, according to an August 14, 2020 report in Morbidity and Mortality Weekly Report (MMWR). This represents a hospitalization rate of about 8 per 100,000 population, compared with 164.5 per 100,000 adults.

Those most at risk for hospitalization include:

• Children younger than 2 years of age (24.8 per 100,000)
• Hispanic children (16.4 per 100,000)
• Black children (10.5 per 100,000)

About one-third of children who were hospitalized were placed in intensive care, which is a rate similar to that seen in adults. About 6% required mechanical ventilation, compared with about 19% of adults. About 4 of 10 had underlying medical conditions, including obesity and chronic lung disease. In children younger than 2 years of age, prematurity was also considered an underlying condition.

As described in the August 14, 2020 MMWR, some aspects of these data are limited by the fact that they represent a review of a convenience sample of patient charts.

Complications — MIS-C

Between the beginning of March and mid-July 2020, the CDC received reports of 570 patients less than 21 years of age with multi-inflammatory syndrome in children (MIS-C), according to an August 14, 2020 MMWR. In 86% of these patients, four or more organ systems were affected. Most often the affected systems included the gastrointestinal tract (91%), cardiovascular system (86%), and dermatologic or mucocutaneous system (71%).

The most common symptoms included:

• Abdominal pain (61.9%)
• Vomiting (61.8%)
• Skin rash (55.3%)
• Diarrhea (53.2%)
• Hypotension (49.5%)
• Conjunctival infection (48.4%)

Common severe complications included:

• Cardiac dysfunction (40.6%)
• Shock (35.4%)
• Myocarditis (22.8%)
• Coronary artery dilatation or aneurysm (18.6%)
• Acute kidney injury (18.4%)

Of patients diagnosed with MIS-C, 10 died. As with infection rates, certain groups are at higher risk for developing MIS-C:

• 40.5% were Hispanic patients
• 33.1% were Black
• 13.2% were White
• Obesity was the most common underlying condition.

Statistical modeling, known as latent class analysis (LCA), defined three types of MIS-C-related cases:

• Class I — 35.6% of patients were in this category, which was defined by the highest number of involved organ systems. Almost half of these (48.8%) had six or more organ systems affected, 100% had cardiovascular involvement, and 97.5% had gastrointestinal involvement. This class was characterized as MIS-C without overlap of acute COVID-19 or Kawasaki disease.
• Class II — 29.6% of patients were in this category, which was defined by respiratory system involvement (76.3%), with symptoms suggesting primary acute COVID-19 or acute COVID-19 and MIS-C together. This class was also characterized by the highest case fatality rate.
• Class III — 34.7% of patients were in this category, which was defined by the highest occurrence of rashes (62.6%) and mucocutaneous lesions (44.9%). This class had the youngest average age patients and aligned more with Kawasaki disease. These patients also had fewer underlying conditions, systems involved, complications, markers of inflammation, and less cardiac damage.

To read more about MIS-C and coronavirus infections in children, access the August 14, 2020 MMWR article.

Death

As SARS-CoV-2 infections tend to be less severe in young people, the number of deaths is also lower. But they still occur. Check out the “In the Journals” section for a review of data presented in the Sept. 15, 2020 MMWR.

Vaccination

Current phase III trials are not being conducted in those younger than 18 years of age. As such, it is not likely that early COVID-19 vaccines will be available for children. We respond to this and other questions related to COVID-19 vaccines on our dedicated page, www.COVIDVaccineAnswers.org.