COVID-19 Transmission In Kids: An Updated Review
The question about the “best” school strategy for the upcoming school year remains hotly debated.
A recent article in JAMA found that children have higher concentrations of SARS-CoV-2 (COVID-19) RNA. Other studies suggest children are less likely to spread the virus. Which is correct? Are children at high risk? And how does it impact school? Here are my updated thoughts, as a pediatrician and as a Mom.
I have reviewed some of the prior studies and discussed school recommendations and strategies in a prior article.
And check out prior posts for questions about mask safety or which masks to choose!
Brief Summary
Some studies support the idea that children are less likely to infect others or be infected themselves. But recent outbreaks in camps and daycares have led to concerns that lockdowns may have impacted our interpretation of the data.
A recent study suggests that the concentration of COVID-19 RNA in the upper respiratory tract of young children is higher than that of older children or adults. But this does not necessarily mean they are more likely to be infectious. It is premature to make assumptions based on a few studies, and we should proceed cautiously until we learn more.
In areas with high infection rates, it is more likely that children could be exposed in their schools and propagate the infection.
Once again, school decisions need to be made taking into account the local infection rates, adherence to public health guidelines such as masking and social distancing, and individual/family risk factors.
Wear the mask.
Data Remains Limited
Unfortunately, data about COVID-19 in children remain limited and contradictory. Some studies suggest that children have lower infection and transmission rates compared to adults. However, because available data were collected in an artificial setting (during lockdown) we cannot truly assess childhood susceptibility to COVID-19. Parents and teachers remain concerned that once schools open, we will see a leap in infections. A few recent outbreaks at camps and in daycares seem to support this fear.
That being said, many daycares and other childcare facilities have been open over the past several months caring for children of essential workers (who are presumably at a higher risk of being exposed to and contracting the virus). Fewer outbreaks have occurred and fewer children have tested positive than expected, especially if they transmit infections at a high rate. Similarly, schools and daycares have opened up in some other countries without an appreciable or attributable jump in infection rates. All outbreaks need to be interpreted in the context of whether or not appropriate guidelines were being followed (was everyone masking appropriately? maintaining distance? etc).
Puzzle Pieces
A recent study in the Journal of the American Medical Association (JAMA) has led to increased concerns because the researchers found that children actually have higher concentrations of SARS-CoV-2 RNA in their upper respiratory tracts.
Taking a closer look:
The study was conducted at Lurie Children’s Hospital in Chicago. Nasopharyngeal swabs were taken from children and adults with symptoms or a high-risk contact, who presented in a variety of hospital settings (e.g., ER, outpatient clinics, or inpatient units). The patients were divided into 3 groups: young children (<5 years), older children (5-17 years) and adults. Younger children had 10-100x higher concentration of SARS-CoV-2 RNA in their upper respiratory tracts compared to older children and adults.
But what does this actually mean?
The study wasn’t perfect (few are). Here are some limitations:
Samples were skewed: the researchers were not sampling randomly from the community—they were doing swabs on patients with symptoms or risk factors who had presented to a medical setting. Extrapolating these conclusions to the community at large is a jump.
Researchers evaluated only the concentration of viral RNA, and not the infectivity or degree of symptoms of the people involved. In other infections, such as RSV, higher RNA concentrations in the respiratory tract are correlated with higher infectivity—but this is not necessarily the case with COVID-19. Some studies have shown detectable levels of SARS-CoV-2 RNA remain for weeks after recovery from infection. So, the presence of viral RNA may not necessarily mean a person is infectious to others.
It is very tempting to use this study to assume that children are just as infectious as adults. The truth is that we don’t know. This study adds to our body of knowledge, as do others (here and here) which actually suggest the opposite: that children are less likely to be spreaders.
At present, our studies are limited by how new this virus is, and the settings in which find ourselves. These are not randomized controlled trials, which would be very challenging (and possibly unethical) to carry out. Although this research is a valuable piece of the puzzle, it is just that: a piece of a complicated puzzle.
Could A Child Start The School Year Infected?
It is certainly possible, and far more likely if you live in an area with high infection rates. A recent article from the New York Times discusses the risk that students could arrive at school already infected with COVID-19. Be aware that these projections assume children are as likely to carry and transmit the virus as adults (which, as I have discussed, is unknown, but probably less likely).
The graphics from the article are helpful and interesting to review (and allow you to calculate the risk in your own county). In the areas of the country with highest infection rates, even smaller groups of students are at risk of someone in their cohort being infected.
So…. What Is The Right Answer?
Unfortunately, we do not yet know. We need to proceed cautiously, not take every new article as gospel, and wait for scientists to do their job: gather data and draw conclusions which can be peer-reviewed and verified by more studies. Improved testing accessibility and turn-around time can help, and will help generate data faster. As I have said before, much depends on your unique situation: the infection rates where you live, the likelihood that your family and community will adhere to guidelines such as mask-wearing, and your individual and family risk factors.
Final Thoughts
Eventually we will have the information we need to understand this virus better. Until then we may need to err on the side of caution and mitigate risk where we can: smaller classes, wearing masks, maintaining a 6 foot distance and ensuring adequate ventilation. As schools re-open the answers will likely become more clear.