COVID-19 in U.S. Children, Early 2020: Fewer Cases, Milder Illness, Different Symptoms

By April 2, 2020, COVID-19 had caused more than 890,000 cases and 45,000 deaths worldwide, including 239,279 cases and 5,443 deaths in the United States. Reports from China suggested that children's illness might be milder than adults' and look different, but nobody had yet described U.S. pediatric cases. This CDC report, first released early on April 6, 2020, was that first look.

The data

• 149,760 laboratory-confirmed U.S. cases from February 12 to April 2, 2020, reported by all 50 states, DC, New York City and four U.S. territories through a standard case report form.
• Age was known for 149,082 (99.6%). Of those, 2,572 (1.7%) were children under 18 — who make up 22% of the U.S. population.
• Big caveat: key details were often missing — symptoms for just 9.4% of cases, underlying conditions for 13%, hospitalization for 33%. So hospitalization rates are given as ranges (all cases vs. only those with known status), and no statistical tests were run.
• Children were compared with adults 18–64, leaving out older adults, whose illness is more severe.

Pediatric COVID-19 cases by date reported to CDC. Image from the Centers for Disease Control and Prevention

Who the children were

• Where: 850 (33%) from New York City, 584 (23%) from the rest of New York State, 393 (15%) from New Jersey, and 745 (29%) elsewhere — similar to adults, except that fewer adult cases came from New York State (14%).
• When: the first pediatric case reached CDC on March 2, 2020; from March 5, new ones came in every day.
• Age: median 11 years.

• Sex: 57% male (1,408 of 2,490 with sex known), against 53% among adults. Males outnumbered females in every pediatric age group, even infants — hinting that biology may play a part, though reasons are unknown.
• Exposure: of 184 children with known exposure, 16 (9%) were linked to travel and 168 (91%) to a COVID-19 patient at home or in the community.

Symptoms

Symptoms were known for 291 children and 10,944 adults aged 18–64.

Of the 78 children reported without fever, cough or shortness of breath, 53 had no symptoms reported at all — though incomplete records meant they could not be called asymptomatic. One more child who tested positive was reported asymptomatic.

Hospitalization

Status was known for 745 children (29%) and 35,061 adults aged 18–64 (31%).

• Infants were hospitalized most: 59 of 95 babies under 1 with known status (62%), five of them in intensive care. For ages 1–17, the range was 4.1%–14%, with little difference between age groups — though most infants' status was unknown.
• Underlying conditions: of 345 children with information, 80 (23%) had at least one — most often chronic lung disease, including asthma (40), cardiovascular disease (25) and immunosuppression (10). Among children whose hospital status and conditions were both known, 28 of 37 hospitalized — including all six in intensive care — had a condition, against 30 of 258 (12%) not hospitalized.
• Three children died; review was still under way to confirm COVID-19 as the likely cause.

Children with COVID-19 by age group and hospitalization status. Image from the Centers for Disease Control and Prevention

How it compares

The findings broadly match a report on Chinese patients under 16: 41.5% had fever, 48.5% cough, and 1.8% needed intensive care. A second Chinese report suggested infection might be more severe in infants. A study of 44,000 cases of all ages in China found a higher case-fatality rate among men, but it — and an analysis of 2,143 Chinese children — found no substantial difference in case numbers between males and females.

Limitations

1. Missing data: overstretched health departments often could not fill in symptoms, severity or conditions — and the gaps are probably not random, so results need caution.
2. Too soon to know: many cases were only days old, so severity and later symptoms may be underestimated.
3. Testing varies: many areas tested the sickest patients first, which would overstate the share hospitalized in every age group.
4. Adult comparison: severe disease is commoner at the top of the 18–64 range, so young adults may be more like children than this suggests.

What it means

• Most children's cases so far were not severe, but serious illness requiring hospital care does happen.
• Children don't always have fever or cough. Clinicians should keep a high index of suspicion and watch for worsening, especially in infants and children with underlying conditions.
• People with mild or no symptoms, children included, likely help spread the virus. So social distancing and everyday preventive behaviors matter at every age — to slow spread, keep health care from being overwhelmed, and protect older adults and anyone with serious medical conditions. CDC's advice included staying home, respiratory hygiene and cloth face coverings around others.
• As cases grew, surveillance would lean more on focused systems gathering full details on a subset of cases, and better data on children's underlying conditions would help show who is at highest risk.

Sources

Based on "Coronavirus Disease 2019 in Children — United States, February 12–April 2, 2020," by the CDC COVID-19 Response Team, Morbidity and Mortality Weekly Report 69(14), Centers for Disease Control and Prevention; a work of the United States government in the public domain. The source counts infants under 1 as both 398 and 393, so only the share (15%) is given; its 77% for hospitalized children with underlying conditions does not match its own 28 of 37, so the counts are given instead.