Recently, as school districts, teachers, parents, pundits and politicos across the country have debated about re-opening schools for in-person instruction vs going to virtual classrooms, many people, including Dr. Scott Atlas, a new Whitehouse medical advisor and coronavirus contrarian, have claimed that school kids don’t often catch COVID-19, and when they do, rarely die from it, and they don’t spread it to other kids or adults in their families. Therefore, they argue for fully opening the schools where kids do not need face masks, or to worry about personal distancing measures.
There are, of course, other issues in this debate, such teacher safety, and how keeping kids at home would hinder the ability of parents to go to work, etc. I don’t intend to lobby here for restarting schools or not. The only issues I will address are whether kids can get COVID-19, be significantly affected by the disease, and spread it to others. In brief, the science informing these three issues says “yes, yes, and yes.”
Kids do catch and spread COVID-19. The science showing that children can readily be infected by CoV-2 is unequivocal. Nevertheless, some people point to other observational data showing that kids do not often get infected and, from that, conclude that children somehow are resistant to the virus. However, these people fail to consider other reasons why children are infected at a low rate. The answer, as I discuss in more detail below, is not due to some intrinsic biological factor that better protects kids than adults from the virus. Rather, the lower rate of infection in kids is due to the early school, playground, and activity closures that have limited their exposure to the CoV-2 virus. In other words, mitigation efforts were effective in preventing virus spread among school kids. And as these social restrictions gradually have been lifted, CoV-2 infections and hospitalizations have increased in children.
According to the latest data from the Centers for Disease Control and Prevention COVID-19 data tracker, about 245,000 US youth from birth to 17 years old have tested positive for the virus. Pediatric cases of COVID-19 increased by 21% in the two weeks between August 6 and August 20 (>70,000 new cases of the disease). Between July 9 and Aug 9, the number of pediatric COVID-19 cases in Florida jumped 137%, while hospitalizations increased 105%. This upward trend in infections and hospitalizations is seen across the US as recently reported by the CDC. One reason for rising infection rates in kids is increased testing, but increased testing does not account for increased COVID-19 diagnoses or hospitalizations. An increase in infection and disease is expected as children are also increasingly being less isolated than they were when schools first closed and playgrounds locked. Relaxation of quarantine measures, along with the persistent and rising CoV-2 infection rate in the US, means that it is expected that more children are being exposed to the virus and coming down with COVID-19.
In March, childhood COVID-19 cases were just 2% of the total, now they are 9% according to a recent weekly report from the Children’s Hospital Association and the American Academy of Pediatrics. Pediatric COVID-19 cases in the US rose 90% between mid-July to mid-August. Also, examples of superspreader events among children are becoming more common around the world (these events are the major drivers of viral spread). There are several reports of such outbreaks among children at foreign schools. A superspreader event also was recently reported at a summer camp in Georgia where one young staffer initiated the spread of the virus to 76% of campers. A total of 260 kids (median age 12), and staffers (median age 17) were infected in just a couple of days—clearly kids can catch and spread the virus. This confirms results reported earlier by the Korea Centers for Disease Control and Prevention, which examined >59,000 contacts from ~6000 pediatric COVID-19 patients and found that infected children between ages 10-19 spread the virus as readily as adults do. Yet another study published in late July in JAMA Pediatrics, reported that kids in this age range carried similar upper respiratory viral levels as adults. Surprisingly, kids five and younger carried 10-100 times the viral genetic material as adults and older kids. The reason for this unexpectedly high viral load in very young children is not clear, but it could be due to the immature immune system children have in their early years that might be less effective in controlling the virus. This finding raises concern that very young infected children could be highly efficient vectors for viral spread, which would fit the pattern seen with other respiratory viruses.
COVID-19 morbidity in children: As I wrote this blog post, a radio talking head in the background announced that since the CDC reports that kids seldom die from COVID-19, there is no reason to keep schools from opening. However, the pundit, like so many others, only considered COVID-19 risk in terms of mortality and failed to take into account the significant morbidity of the disease. While it is true that, compared to adults, fewer kids die or get seriously ill with COVID-19, many children, even those with mild or asymptomatic forms of the disease, develop a post-infection condition called multisystem inflammatory syndrome in children (MIS-C) that can lead to organ failure and possibly long-term health problems. This is a condition reminiscent of toxic shock syndrome where different organs including the heart, brain, lungs, kidneys, skin, eyes and GI system become inflamed. As early as last May, the CDC issued a health advisory to pediatric doctors alerting them to this new complication of COVID-19, which was first reported in April by doctors in the UK. More than half the MIS-C cases are under nine years old with the median age being eight. As of August 20, A CDC tracker reports that the US has seen almost 700 serious cases of MIS-C, and about 5000 children were reported with a less severe form of MIS-C. Because the disease is so new, the long term consequences of this systemic inflammatory response is not known. For that reason alone, caution is warranted as we try to get a handle on this novel complication and understand its long-term consequences.
Most children with MIS-C require ICU hospitalization and can experience symptoms that last for weeks. It is often accompanied by subtle changes in myocardial function where the heart’s left ventricle, or main pumping chamber, is impaired. This is the chamber that pumps oxygenated blood arriving from the from the lungs to the rest of the body. At the Children’s Hospital of Philadelphia, 17 of 28 MIS-C patients showed this myocardial injury as reported in the Journal of the American College of Cardiology. Over a brief followup period, affected patients tended to recover systolic (pumping) function, but diastolic (resting) dysfunction persisted.
A recent report in Nature Medicine, indicates that MIS-C isn’t a direct result of the virus, but is likely due to an intense autoimmune response, akin to a cytokine storm, to the infection. This very unexpected consequence of the disease represents one of the several novel aspects of COVID-19 that we have had to very quickly recognize and just as quickly learn how to deal with. The good news is that we are steadily learning more about the disease and making headway in knowing how to treat it. The bad news is that it will be years before we can fully understand what all this means for the long-term health of these pediatric patients.
Biomedicine is wonderfully interesting for those who have patience.
Bottom line: As of July 24, the CDC recommended that K-12 schools reopen this year. On the other hand, a study published last month in The Journal of the American Medical Association estimated that by closing schools in March, we reduced the rate of new COVID-19 cases by 66%. If the JAMA report is accurate, it means that about 1.4 million fewer people became ill and about 40,600 fewer people died, which argues against re-opening schools for in-person instruction.
What would you do?