• Harlan Gallinger, MD

Young Children are Less Susceptible to COVID-19 Transmission & to Spreading COVID-19

The research is very consistent across the globe that young children appear to be less susceptible to acquiring COVID-19, not only in the community, but even within households. In a population study in Iceland with targeted testing of symptomatic or high-risk individuals based on international travel with viral PCR testing, “Children under 10 years of age were less likely to receive a positive result than were persons 10 years of age or older, with percentages of 6.7% and 13.7%, which is about 50% less likely. More importantly “in the population screening, no child under 10 years of age had a positive result, as compared with 0.8% of those 10 years of age or older.”(4) While it could be argued that the acute phase of illness was missed in young children, especially with testing prioritization, a population study of IgG serology on households in Geneva, Switzerland, again notes that young children did not have evidence of COVID-19 acquisition. The study notes that a “single positive young child out of 123 in our sample suggests that infection was less prevalent in children than in adolescents and adults during this epidemic.” Out of the 123 children mentioned “21 (17·1%) of them had at least one seropositive household member,” which further supports the theory that even when exposed children are far less likely to acquire COVID-19.(5) An early study out of China noted that even within households with COVID-19, “the data-based secondary attack rates were lower in the youngest age group (age <20 years 5∙2% than the 20–59 years age group 14∙8% and the oldest age group age ≥60 years 18∙4%).”(6)

These studies provide data that supports the notion that young children are neither asymptomatic carriers nor super spreaders of COVID-19. In fact, young children are likely to have physiologic protection from COVID-19 based on their limited expression of the ACE2 receptor which will be evaluated further in the HEROS study in the United States.(7) Australia’s National Centre for Immunisation Research and Surveillance published results from contact tracing and viral PCR/serology testing of close contacts and found that 18 individuals (9 students and 9 staff) from 15 schools were confirmed as COVID-19 cases; all of these individuals had an opportunity to transmit the COVID-19 virus (SARS-CoV-2) to others in their schools. 735 students and 128 staff were close contacts of these initial 18 cases. No teacher or staff member contracted COVID-19 from any of the initial school cases.(8) This is important evidence that must be considered in the formulation of any school reopening strategies. [see Figure 1 and Figure 2]

Certainly when we look at the impact of school reopening in Denmark and the Netherlands, it appears to confirm that in general young children do not spread COVID-19 and these countries have continued to see decline in new cases. [Figure 3] More importantly reopening of schools have provided important data so that their research notes that the “spread of COVID-19 among children or from children to adults is less common.” The Netherlands have been testing educators of young children and “[b]ased on data from the GGD test lanes, 66 (2.5%) of these 2619 employees tested positive in the first month. This percentage is lower than the total of 8.2% of all people tested in the test lanes, and also lower than the 6.9% of all these people excluding healthcare workers. Moreover, there was no increase in the percentage of employees working in childcare and primary education who tested positive this month.”(9) Like the study from China and Australia, the Netherlands followed contact tracing in children for the ”10 COVID-19 patients who were <18 years old, they had 43 close contacts, and none of them became ill, whereas 8.3% (55/566) of the close contacts of the 221 patients who were ≥18 years old became ill.”(8)

So the question is: if young children do not acquire nor transmit the virus in any meaningful or statistically significant fashion, then why would these children be deprived of their education, during the formative years when it is most critical. Zoom kindergarten is not effective, nor are intervention for our students with special needs, learning English, and who need additional social supports. Given the impact of last spring and the potential impact of this fall, there is a high likelihood that these children will never close the educational gaps which will have a lifelong impact on educational status, earning potential, and long-term health far beyond childhood. Truly, the impact of school closure due to COVID-19 is likely to be added to the list of Adverse Childhood Events (ACEs) when researchers fully assesses the impact on our students. If young children do not acquire nor transmit the virus, the data would suggest and support that the Washington State Department of Health mandates for masking, physical distancing, and busing will do more harm to these children. As you know in medicine, one of primary pledges to our patients, it to first do no harm. The proposed guidance is harmful to young children and without evidence to support based on impact to students or teachers either within our state as our schools were open for two months while COVID-19 was circulating in Washington state (mid January to mid March) or through international data or peer-reviewed literature.

Figure 1. Cases and close contacts among teachers and students in 5 NSW primary schools showing one secondary case in a student (8)

Figure 2. Cases and close contacts among teachers and students in 10 NSW high schools showing one secondary case in a student (8)

Figure 3. Number of new coronavirus (COVID-19) cases in Denmark since February 2020, by date of report (13)


4. Gudbjartsson DF, Helgason A, Jonsson H et al. Spread of SARS-CoV-2 in the Icelandic Population. N Engl J Med 2020; 382:2302-15.

5. Stringhini S, Wisniak A, Piumatti G, et al. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV-POP): a population-based study. Published online June 11, 2020.

6. Qin-Long Jing, Ming-Jin Liu, Zhou-Bin Zhang. Household secondary attack rate of COVID-19 and associated determinants in Guangzhou, China: a retrospective cohort study. Lancet Infect Dis 2020. Published Online June 17, 2020 S1473-3099(20)30471-0.






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