Children Under Age 12 Do Not Transmit SARS-CoV-2

The deadline for choosing between "virtual only" and "in-person" classes for Fairfax county parents and teachers is tomorrow. Data on how schools contribute to the spread of COVID-19 is unfortunately scarce. There is, however, a town in France, Crépy-en-Valois, that has recently provided an answer to this important question. The study, not yet peer-reviewed, has been made available in MedRxiv. Although the paper is still in a pre-print stage and should not be used to guide clinical practice, it may be useful as we try to deliberate on what to choose for Fairfax county schools. The study authored by a group of epidemiologists and virologists from Paris has also been mentioned in a Science article that summarizes what we now know about COVID-19 and children.

Above copied from Science

Out of the 1340 individuals included in the study in Crépy-en-Valois, 139 are infected with SARS-CoV-2. That is 100,000 people if the total population is 1,000,000. New York, the state that has the most cases, has only 22,000 cases per million. The following shows the distribution of COVID-19 cases in the study:

Above copied from Fontanet et al. (2020)

Nearly 9 percent of pupils are infected. The fact that 61 percent of the parents of infected pupils have COVID-19 suggests that the transmissions occurs from parent to child and not vice versa. Since the percent of teachers infected matches those of parents of non-infected pupils, there is likewise no sign that pupils can infect their teachers. These results are in stark contrast from another study by Fontanet and coworkers where high school students aged 15-17 years old are clearly transmitting the virus.

Above copied from Fontanet et al. (2020)

Here, 40 percent of 15-17 year old pupils are infected. Both teacher and school staff also have similar percentages of infection, 43 and 59 percent, respectively, which are much higher than the rate of infection for parents. This suggests that transmission must have occurred primarily inside high schools. 

At this point, how to open schools requires us to look at what is already known from other places. The main problem is we often confuse news with data. Seeing a headline that says cases have been discovered in a daycare, for instance, does not really inform us, especially when there is a widespread community transmission occurring. What is required is how transmission is occurring. The above studies in France tell us that children under the age 14 are not likely to spread SARS-CoV-2, but high school students are no different from adults. This difference tells us that we need to look at these age groups differently. High school students are much more similar to college students or young adults. Therefore, what we do with K-12 schools this coming Fall should be different between K-8 and grades 9-12.