What Experts Know About Children, Covid and Omicron

(Bloomberg) -- Covid-19 cases among children have surged across the world amid omicron-fueled outbreaks, spurring more hospitalizations and raising fresh concern about the risk of severe illness -- although such cases remain proportionately rare. It’s also renewed questions about the safety of schools and the potential for prolonged health effects. 

1. How common is Covid in children?

Reported Covid-19 cases among children spiked dramatically in 2022 during the wave driven by the hyper-infectious omicron variant, according to the American Academy of Pediatrics. Almost 4.5 million pediatric cases were reported in the U.S. in the first six weeks of the year. Pediatric cases peaked at 1.15 million in the week ending Jan. 20 and were still at “extremely high” levels in early February -- well above what was observed during the peak of the delta surge in 2021, it said. The 298,931 cases of Covid-19 in children in the week ending Feb. 10 represented 21.9% of the weekly reported infections across the U.S. That jump in sheer numbers infected has also translated into more Covid-related hospitalizations.

2. What are the symptoms of omicron?

Omicron’s symptoms are similar to those of other SARS-CoV-2 variants. Sore throat, fatigue, aches including headache, dry cough, congestion and fever are frequent signs, though taste and smell distortions are reported to be less common, according to the Children’s Hospital of Chicago. Overall, the strain causes less severe symptoms and appears to be milder. Pediatricians report that omicron is bolstering cases of croup, a common childhood illness typically caused by seasonal viral infections that leads to inflammation or swelling in a child’s upper airways, which are smaller than in adults and which omicron appears to target. An analysis of emergency department data at Seattle Children’s Hospital found that the incidence of croup almost doubled during the omicron surge compared with the rate in prior months. 

3. Why are children being infected more?

Omicron has a significant growth advantage over delta, the variant that prevailed during 2021, and is better than earlier strains at evading immunity acquired from vaccines and natural infection. That’s enabled it to spread rapidly in communities, especially among susceptible individuals across all age groups. There’s no evidence that omicron is targeting children more than other age groups, but vaccination rates are higher in older people since adolescents generally got access to the shots much later. In the U.S. and many parts of the world, children younger than 5 aren’t eligible for Covid vaccination, and kids ages 5 through 11 aren’t eligible to receive boosters. 

4. How serious is an omicron infection for children?

Covid-19 remains a mild disease in the vast majority of children, and there’s no evidence that omicron is changing that. Early data suggest that, as with all other variants, severity increases with age and in the presence of underlying medical conditions, as well as among people who aren’t vaccinated. 

• A U.S. study using a nationwide database of electronic health records found that the risk for hospitalization in unvaccinated children younger than 5 that occurred after the emergence of omicron was a third of that during the delta variant wave. The risk for an emergency department visit was less than a fifth, it found. The same trends were observed for children 5-11 years and 12-17 years old. The results, released in January ahead of peer-review and publication, suggest that although pediatric infections and hospitalizations have risen during the omicron surge, cases are milder compared with the period in which delta predominated.
• Often children are hospitalized for other reasons and coincidentally test positive for SARS-CoV-2. The presence of an underlying condition among children ages 5-11 years is associated with about 12 times higher risk of hospitalization and 19 times higher probability of admission to intensive care. Among U.S. states reporting Covid case data:
  • children accounted for 1.5%-4.6% of their total cumulative hospitalizations
  • 0.1%-1.5% of all their pediatric Covid-19 cases resulted in hospitalization
  • 0.00%-0.01% of all pediatric Covid-19 cases resulted in death
• Some children who have had Covid may later develop a rare but serious condition known as Multisystem Inflammatory Syndrome in Children, which has been reported in almost 7,000 kids and adolescents in the U.S. since the start of the pandemic, killing at least 59 as of Feb. 14. The incidence of MIS-C hasn’t increased in the U.S., despite a large increase in omicron cases there.

5. Why are children less likely to get severely ill?

Children have a more robust innate immune response -- the body’s crude but swift reaction to pathogens -- than older adults. That typically enables kids to successfully counter the infection before it’s had a chance to spread to the lungs to cause pneumonia and the inflammatory cascade that can be life-threatening in seniors. It’s also possible that the routine pediatric immunizations that younger children receive boost their innate immune response.

6. Are children more likely to transmit omicron?

Omicron is inherently more transmissible and, therefore, will be more contagious between people of any age. Studies and modeling of transmission patterns indicate that younger children and adolescents play a lesser role in spreading the coronavirus at a population level, and that prioritizing vaccination in older age groups yields more population-level protection against Covid. 

7. What about at school?

As students return to classes, the U.S. Centers for Disease Control and Prevention recommends prevention measures in early child care and schools, such as masking for students and staff members and maintaining adequate ventilation to reduce transmission of the virus. One study using computer modeling, released ahead of peer-review in August, indicated universal masking could reduce infections among susceptible students by 26% to 78%, and biweekly testing along with masking by another 50%.

8. Can children get ‘long Covid’?

It’s possible. There are no data so far on the incidence of prolonged symptoms due to omicron or whether it differs from previous variants. An analysis of published studies by researchers in Switzerland and Australia found that long Covid might be less of a concern in children and adolescents than in adults, with symptoms typically persisting for less than 12 weeks. Still, the authors found that studies of the likelihood of persistent symptoms in children are limited and difficult to interpret. In some cases, children who had an infection weren’t compared with uninfected “controls” to identify whether chronic fatigue, anxiety and other ailments could be indirect consequences of the pandemic, such as lockdowns and school closures. In one large, self-selected, online study of young people, only 13.5% of eligible participants responded, leading to a potential response bias, for example, toward those experiencing lingering symptoms being more motivated to participate, resulting in an over-representation of symptom prevalence. 

The Reference Shelf

• CDC guidance on schools and child care programs, pediatric Covid vaccination, and its data tracker.
• The journal Pediatrics looks at risk factors that could put infants and children at higher risk of developing severe Covid.
• The Children’s Hospital of Chicago answers frequently asked questions about omicron and children.
• Murdoch Children’s Research Institute’s surveillance report on Covid-19 and children.
• Pediatricians Anna Sick-Samuels and Allison Messina answer questions on Covid vaccines and children.
• The BMJ discusses the steep rise in omicron-linked hospitalizations of the very young.
• Bloomberg’s global vaccine tracker.
• More QuickTakes on long Covid, the case for boosters, vaccine mandates and mRNA.
• Bloomberg Opinion’s Sam Fazeli looks at the U.K.’s single-shot approach for children.

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