Spread of COVID-19 in children and symptoms in children

On-Site Staff

June 22, 2020

Knowledge of how COVID-19 affects children is very scarce due to initial beliefs that children are affected less than the general population.

Recently, there has been a lot of discussion regarding the spread of COVID-19 among children, the effects the disease has on this population, and the possibility of youngsters dying from this disease. At the beginning of the pandemic, it was said that children are not as prone to getting COVID-19 in comparison to adults, although they can often be asymptomatic carriers (1). Childhood infection trends have changed throughout the COVID-19 era, especially after massive outbreaks in big cities, where numerous children developed new symptoms, and some died from COVID-19 (2). As of now, it is known that 1-5% of all COVID-19 cases are recorded in the pediatric population and that children can be affected differently than adults (2). It has been observed that children develop milder symptoms and that this population has less chance to get the disease at all (3). According to the Washington Post, there are not only fewer children affected by the disease, but if they do get it, fatalities are rare (4). The debate also focuses on the fact that children can still become infected and can spread the virus to others, including older family members, who are more likely to have a severe illness.

Symptoms of COVID-19 in children
Knowledge of how COVID-19 affects children is very scarce due to initial beliefs that children are affected less than the general population. Among the initial symptoms of COVID-19 infection in children, fever and cough are cited most (1). Because children are not affected as often as adults, especially immunocompromised adults, they have not been a topic of discussion until the recent changes in clinical presentation, referred to as Kawasaki-like syndrome or multisystem inflammatory syndrome. Several weeks after the pandemic started, the second wave of symptoms was observed among children exposed to COVID-19. According to The Atlantic, patients coming into hospitals were presenting with multiorgan inflammation and some combination of “fever, rashes on their hands and feet, diarrhea, vomiting, and very low blood pressure” rather than respiratory distress (5).

The theory of why children are affected differently
The way children are affected differently than adults can be explained, based on a theory, that a child’s immune system is still-developing (5). During recent months, when the pandemic became uncontrolled in several large cities in the US, including New York City, it became apparent that children can develop a cluster of symptoms named multisystem inflammatory syndrome (also referred to as a pediatric multisystem inflammatory syndrome, pediatric inflammatory, multisystem syndrome temporally associated with SARS-CoV-2, pediatric hyperinflammatory syndrome, or pediatric hyperinflammatory shock) a condition that resembles Kawasaki syndrome (6). These inflammatory changes delay the response of the young body to a new virus. Because the immune system in children can adjust much faster to a new pathogen (with mostly all diseases being new to children at first encounter), this makes them much better at fighting new viruses and bacteria, compared to older populations, who have “primed” immune responses, that can fight familiar agents but may struggle to recognize and fight novel pathogens, like COVID-19.

Multisystem Inflammatory Syndrome in Children
There have been cases of multisystem inflammatory syndrome in children (MIS-C), also called “Kawasaki-like syndrome” in children with COVID-19. Clinical presentations are sporadic but life-threatening. The condition is described in the literature as a rare, acute, pediatric vasculitis, including persistent fever, exanthema, lymphadenopathy, conjunctival injection, and changes to the mucosa and extremities (7). An interesting fact about this syndrome is that it is a post-infectious complication of the virus rather than something occurring during acute infection. Presentation in some children can occur several weeks after the peak of infection in their community (6). Another difference between Kawasaki-like syndrome caused by COVID-19 infection and true Kawasaki disease is the age of affected children. In true Kawasaki disease, most children affected are up to one year old. In the post-COVID-19 population, affected children tend to be older, including adolescents (6). Kawasaki-like syndrome has been detected in previously healthy children and adolescents (it was first documented in April in the United Kingdom, then the US, Canada, and other countries) and similar to adults with preexisting conditions, these cases may have worse outcomes, even in previously healthy children with no preexisting conditions (6).
The bottom line is that children are minimally affected by this viral disease, but can develop a fatal post-infectious syndrome, regardless of pre-COVID health status. Therefore all attempts should be made to prevent viral spread among children (2). Decreasing viral spread will undoubtedly be a challenge for this population, with numerous communities preparing to reopen schools.

1. Singhal T. A Review of Coronavirus Disease-2019 (COVID-19). Indian J Pediatr. 2020 Apr;87(4):281–6.
2. Ludvigsson JF. Systematic review of COVID‐19 in children shows milder cases and a better prognosis than adults. Acta Paediatr. 2020 Jun;109(6):1088–95.
3. Barclay Laurie. Most Children with COVID-19 Have a Less Severe Course? [Internet]. 2020 [cited 2020 Jun 16]. Available from: https://www.medscape.org/viewarticle/931668
4. Joel Achenbach. Children are only half as likely to get infected by the coronavirus, research shows [Internet]. 2020 [cited 2020 Jun 16]. Available from: https://www.washingtonpost.com/health/children-are-only-half-as-likely-to-get-infected-by-the-coronavirus-research-shows/2020/06/16/be86aff4-afb6-11ea-856d-5054296735e5_story.html
5. Zhang Sarah. Why the Coronavirus Hits Kids and Adults So Differently COVID-19 is much less severe in children, and it could have to do with a child’s still-developing immune system. [Internet]. [cited 2020 Jun 16]. Available from: https://www.theatlantic.com/science/archive/2020/05/covid-19-kids/611728/
6. Coronavirus disease 2019 (COVID-19): Multisystem inflammatory syndrome in children - UpToDate [Internet]. [cited 2020 Jun 16]. Available from: https://www-uptodate-com.unh.idm.oclc.org/contents/coronavirus-disease-2019-covid-19-multisystem-inflammatory-syndrome-in-children?search=covid%2019%20children&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
7. Viner RM, Whittaker E. Kawasaki-like disease: emerging complication during the COVID-19 pandemic. The Lancet. 2020 Jun;395(10239):1741–3.