Are children less likely to spread Coronavirus than adults?
As with most things related to Coronavirus, we don’t yet know for certain. Fortunately, there are some big studies underway to answer this question and there is some preliminary data that seems promising, but most investigators are afraid to fully trust the incomplete data. In the US, kids under 18 years of age represent 2% of the known coronavirus cases and it is known that they are more likely to be asymptomatic or to only have mild symptoms. There is some suspicion (or maybe hope?) that they may be less contagious than adults, especially when looking at young children (up to about age 10). In one ongoing study in the US by Brown economist Emily Oster, data collected from childcare centers points to low transmission rates in younger children in schools and among staff. However, the investigator herself says “that she’s ‘reluctant’ to glean too much actionable information from her findings.” Her data reveals that of 27,000 students surveyed, there were 42 cases (0.15%) of COVID-19 and among the 9,000 staff members, there were 106 (1.1%) confirmed cases. Of course it is very likely that the cases are under-reported as not everyone is being tested and there are likely more asymptomatic cases. That said, this data does resemble information coming out of other countries as well. A study out of France looked at 600 children under 15 years who were in school and found that kids are both “less contaminated and less contaminating, and that in 9/10 cases, it was infected adults contaminating the children.” The reasoning behind why kids are less likely to get it and less likely to spread it is not known, but scientists suspect they have fewer virus receptors in their mucous membranes, they may have better cross-immunity because they’ve been infected with other coronavirus types and their constantly running noses may help them resist infection better. A study in Wuhan found that children are about 1/3 as susceptible to infection as adults, but the trouble is that when schools are open as normal, kids have 3 times as many contacts as adults and thus 3 times more chances to get infected.
So what does all of this mean? We don’t know for certain what will happen as more and more children head to summer camps, back to daycare or back to school in the fall. We do know that the CDC has set recommendations for all of the above and that most importantly, enforcing hand washing, strict health screening policies, limiting the number of interactions (keeping groups small without mixing), and wearing masks and maintaining social distancing when possible and appropriate will help keep our kids and our communities safe. Each family will continue to have to reassess their own risk-tolerance as the situation continues to evolve. The good news is that Yale has just completed a large study looking at kids in school settings and the NIH is conducting a study specifically to look at incidence of COVID in US children, so we will be following for results as soon as they become available.
(Jackie Phillips, MD, June 29, 2020)