Excellent Info: Follow up to…Deciding on Schooling During A Pandemic

I wanted to give an update on the research regarding COVID in children.

I should back up briefly and state that I am a physician with a PhD in Epidemiology who became very interested in this topic when a colleague and friend of mine, Jennifer Kasten, MD MSc, wrote a systematic review of COVID epidemiology in children (https://www.facebook.com/jenniferkastenmd/posts/128898328763114) and found kids 12 and under *might be viral “dead ends”, meaning they can get COVID but can’t transmit to anyone else. This really captured my interest because this would make COVID very different from most respiratory viruses we know (although very similar to SARS COV1, which only had one known case of transmission from a child 18 or under https://www.medscape.com/viewarticle/551274?fbclid=IwAR0WfAoG_VshFrXYqXaSeafrA0pF48yVBpvhllJ9enIZXcNQ-Tx0zJdyRxw). Then in a physician’s group dedicated to school opening, a physician researcher published a document for the group in which said she could identify 0 (zero) cases of certain transmission of COVID from children under 12 in the scientific literature and since that time Dr. Rutherford, UCSF Epidemiologist, has also been public about elementary-aged children being a “one way street” for infection – they get it but don’t appear to transmit it, much, if at all. (UCSF Grand Rounds lectures are now available on YouTube for those interested in hearing him).

Last month, I did my own summary of the data (https://www.facebook.com/tracy.hoeg/posts/10219217323357158) and found evidence of the following:

*Very limited transmission if any from children ages 12 and under to either other children or adults

*Children appeared to be at least 10 times more likely to die of influenza than Covid and are more likely to be struck by lightning (I rechecked the CDC website today 7/13 and they are still reporting 3 deaths in children under 18 due to confirmed COVID; for comparison, there have been 185 deaths due to influenza in this population in the 2019/2020 season. Edit: see updated mortality data below from the 7/19 addition).

*Countries that reopened elementary schools as a first step in their country’s reopening did not see an uptick in cases (these include numerous European and Asian countries, some of which are displayed in Figure 4). Reopenings not causing and uptick in cases is consistent with children not being a major vector for the disease. Figure 3 shows age of the source of the cases of COVID in Holland, with none ages 18 and under in their study, as just an example of these data.

What have we learned in the last month?

1. We now have a generally accepted mechanism for younger children getting milder disease and transmitting significantly less than adults, which is paucity of ACE2 receptors in the respiratory tract compared with adults (this is the receptor SARS COV2 and SARS COV1 use to enter the cells of the body). This could explain why children get COVID (and SARS 1) less, have milder disease (lower viral load) and are less contagious (if contagious at all). Yet another way COVID is unlike typical influenza! https://jamanetwork.com/journals/jama/fullarticle/2766524

(Figure 2)

2. Consistent with this was the study showing lower viral load (lower amount of the virus) in children up to age 18. (Figure 1). The original non-peer reviewed print of this article from Drosten et al was reanalyzed as per UCSF Grand Rounds and does indeed show significantly lower viral load in children as seen in image 1.

3. This is great news for teachers and children, because not only are children significantly less likely to transmit COVID, but IF they do, the dose of the “inoculum” will be expected to be lower and there is mounting evidence (lit review here: https://www.facebook.com/tracy.hoeg/posts/10219560737982309) that the lower the dose of the virus you get, the less severe your disease will be if you even get symptoms at all. This may be why Denmark and Norway were able to reopen elementary schools without any mask wearing in children (or adults for that matter!); however, they also had lower prevalence in the population on their side! Now, in the US if adults and children in school are able to wear masks, this will both lower the risk of transmission (which appears to be very low FROM the 12 and under age group) as well as the severity of the disease.

4. I am sensing many of your are STILL skeptical we can safely open elementary schools in the US. Well, thankfully we have really good data from the YMCA childcare for essential workers in the US, which has been providing childcare throughout the pandemic (our kids go there) and was even open in NYC at the height of the outbreak and they have had 0/>40,000 kids (ages 14 and under) contract COVID. They have also not had any outbreaks, though a few staff at different sites tested positive (presumably contracted from another adult per the above data) and quarantined so no more than 1 positive case a just a limited number of sites. Adults wear masks, kids don’t, temperature checks at the door, each kid has a small “cohort” of kids they do everything with. More details can be seen in this article, but it shows that WE CAN DO THIS SAFELY in the US – even in areas hit severely by the virus and with truly minimal resources. https://www.npr.org/2020/06/24/882316641/what-parents-can-learn-from-child-care-centers-that-stayed-open-during-lockdowns

Edit: The small cohorts in children may actually not be necessary and the data I am using to support this is guidelines for return to school in Holland in quotes below and from their Ministry of Health Website (https://www.rivm.nl/en/novel-coronavirus-covid-19/children-and-covid-19). This model has worked for them:

“Children up to and including 12 years of age do not have to keep 1.5 metres apart from each other and from adults. This also applies to childcare and primary education.”

Edit: Though the above has worked in Holland, given the prevalence of the disease in the US and the possibility children can spread the virus (though apparently much less efficiently than adults), it would be best to have children wear a mask, even in this age group, as it could further minimize risk of transmission, with very little downside, even if compliance is not 100%.

–I also want to briefly address the many “clickbaity” articles in the popular press lately about school and day care outbreaks. Specifically I will mention the school outbreaks in Israel where there were some infections in high school aged children but the “outbreaks” in the elementary schools were among adults only. And the major high school outbreak occurred after the mask mandate was lifted due to a heat wave. Also, if you carefully look at the reports of day care outbreaks in our country, most appear to be involving staff that infect each other and, if kids are affected they are infected by the adults and are asymptomatic/have mild disease. I challenge you all to look at the articles coming from the popular press with the above data in mind and you will be surprised in the elementary age group that the adults appear to be the ones responsible for the outbreaks (though it is hard to get all of the info from those articles) and the ones who are severely affected by the disease.

–What are the bottom lines?

1. Kids 13-14 and below (likely around puberty) do not appear to be driving the spread of COVID. They rarely (one can never say never) transmit the disease. Tracing the source case with 100% certainty can be very challenging, but the data overall indicate pediatric transmission to be quite rare compared with adults.

2. Kids up to 18 years of age tend to get mild disease if any symptoms and death in this age group is less likely than getting hit by lightning. (though as we see higher prevalence in the US, the numbers will be rising)

3. In school settings, adults can and will give to adults and kids, so teachers need to be socially distancing while at work. Adults also should be wearing masks and getting tested and staying home if they have symptoms.

4. Data and guidelines from Holland suggest distancing among children <14 may not be necessary. And reopening of schools in Scandinavia has been successful even without children wearing masks. It should be pointed out that these countries opened schools as the FIRST step of reopening their economy and as stated above, the wearing of masks in elementary schools by students could further decrease any risk of transmission in the US.

5. I have previously discussed the many downsides of not having kids in school in person this fall: further entrenching socioeconomic disparities, job loss for parents who can’t afford childcare worsening poverty and neglect, abuse of children (which will be undereported), lack of support for children with special needs, anxiety, depression and lack of physical activity and peer relationships in children. The list goes on and on. But I want this post to focus more on the science of the disease so it can inform our public policy decisions.

6. I hope the above data are reassuring. The more we know, the better we can tackle and live with this disease.

Edit: Now that this post has been shared hundreds, scratch that, thousands of times (never imagined this), I want to say first of all, that I in no way am intending to detract from the seriousness of COVID-19. It is imperative our country get this disease under control -by social distancing, closing indoor businesses which are not essential and wearing masks, but the above data at least suggest to me that children are not driving the pandemic; adults are. And I also want to say that a lot of what I shared above was recently discussed in the UCSF combined Medicine and Pediatric Grand Rounds lecture (an inspiration for me to write this to get this scientific info to the public). I encourage anyone interested in the above data to watch this recording of the Grand Rounds : https://www.youtube.com/watch?v=yh9gmca6o_A&feature=youtu.be&fbclid=IwAR2HH3myAdjOBmebb23iI2DWPSkdYrEp2niYa_KRiwWStxrqN5f6JNxXPD4

And this article about the above UCSF physicians’ stances on reopening schools and transmission in children: https://missionlocal.org/2020/05/ucsf-medical-grand-rounds-the-doctor-is-ready-to-send-children-back-to-school-with-care/

I welcome any data or questions you have. The science about COVID in pediatrics is evolving and we don’t have all the answers (far from it), but I hope people can use the above data to help them make informed decisions about children’s activities and school openings.

Now, I ask yourself as you are reading this to consider: Is elementary school an “essential service” at least where there are working parents? All other first world countries seem to realize that you can not open the economy until kids have somewhere to go (and preferably learn and be familiar and comfortable with the place!). When one considers the number of couples or single parents who are essential workers, or now working again in the US, with kids too young to watch themselves – I ask you- where will they go if not to school? And will the alternative be better? Children of working parents do need to be cared for (this is why many day cares and summer schools have been open up to this point). We as a society need to do a risk calculation together and decide, based on the science, where the best place for these children is (school vs. day care vs. being left alone vs parents quitting their jobs) and who should take on the risks of caring for them/teaching them (teachers vs. day care workers vs. school proctors (as they are doing in Arizona), etc)? We also need to consider in this calculation what the short and long term risks are of kids NOT being in school (loss of learning, inability to report abuse, neglect, loss of school meals, exercise, social interaction, inability to escape poverty, loss of individualized education plans for children with special needs). It is our job together as American people to figure out what is in the best interest of all our children (regardless of socioeconomic status) – they are truly the future of our country and figuring how to open schools safely is infinitely more important than reopening Disney World (WHY is this open??). Will we in the future look back and say we did right by our children by keeping them out of school for COVID? I hope we can use the above data and strategies of other countries (as well as our own YMCA daycares!) that have successfully managed this pandemic to guide us. Whatever we decide as a society, it needs to be science-based and with our children’s bests interests at the center.

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Edit to add new data:

7/16: In Germany, a study of over 2,000 children: “Scientists from Dresden Technical University said they believe children may act as a “brake” on chains of infection.” https://news.yahoo.com/german-study-finds-no-evidence-164704005.html

7/16: Study performed by the Swedish and Finish Ministries of Health “closure or not of schools had no measurable direct impact on the number of laboratory confirmed cases in school-aged children in Finland or Sweden. The negative effects of closing schools must be weighed against the positive indirect effects it might have on the mitigation of the covid-19 pandemic.” https://www.folkhalsomyndigheten.se/contentassets/c1b78bffbfde4a7899eb0d8ffdb57b09/covid-19-school-aged-children.pdf

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7/19

Per the CDC as of 7/15 for time period 2/1/2020 – 7/11/2020

# of COVID deaths ages 1-14 is 22

# of influenza deaths ages 1-14 is 87

In newborns 0-1 the numbers are much closer: 9 for COVID vs 14 for influenza.

An important thing to point out is we are missing the denominator for these calculations. It will be a challenge to determine the death rate of COVID until we know how many total cases there are and with many ages 1-14 suspected of being asymptomatic, this will be a challenge, and the true death rate for this population will probably need to come from a country that has done EXTENSIVE population-based testing which is not based on symptoms. Keep in mind that unless hospitals are completely full that disease prevalence in a country should not affect mortality rate.

https://data.cdc.gov/NCHS/Provisional-COVID-19-Death-Counts-by-Sex-Age-and-S/9bhg-hcku?fbclid=IwAR0fgYc4Yl-BJt3h9-OhMK-XqbJLWL2sh10WsIe1FLPNpEVOCKbaunBaGpg

This study from France (https://www.medrxiv.org/content/10.1101/2020.06.25.20140178v2.full.pdf) looked at 3 students in primary school with COVID-19 while in school and they did extensive contact tracing and found these students went on to pass the disease to 0/1047 pupils and 0/51 teachers.

I also want to touch on the South Korean study that was mentioned in the New York times (https://www.nytimes.com/2020/07/18/health/coronavirus-children-schools.html?smid=fb-share&fbclid=IwAR2W6LE4j0rxBtE–rLCs8oLoU-7WGRK1K8_6ngbUPaBbyOxhyeu8ouTLe0). This was a nice, large study which found in the 10 and younger age group the following amounts of transmission: 1% for non-household contacts

5% for household contacts

This age group also made up only 6% of the total cases in the population.

However, the important caveat with the study (https://wwwnc.cdc.gov/eid/article/26/10/20-1315_article) is they state “we could not determine the direction of transmission” (meaning they could not determine if it was the child who transmitted to the adult or vice versa). So instead of more rigorous contact tracing, as in the French study above, they did the following: “Because we could not determine direction of transmission, we calculated the proportion of detected cases by the equation [number of detected cases/number of contacts traced] × 100, excluding the index patient”.

Using a calculation such as this as a substitute more rigorous contact tracing could result in an overestimate of the number of transmissions from the youngest group, if this group truly had few to no actual transmissions. So, this South Korean study, while large, does need to be looked at with this limitation in mind and in the context of the other studies that have been done in this age group. The South Korean study does reaffirm what has already sadly been found in previous studies, which is “older” children seem to transmit as efficiently as adults. The problem is, previous data have suggested this change to adult-like transmission likely occurs between the ages of 12 and 14, so it would be really nice to see a sub-analysis of the 10-13 or 10-14 year olds in the final version of this study (what is published is a “pre-print”). I suspect because the study was designed in March that the data were not available yet to suggest they should do that subgroup analysis.

7/25

Mark Woolhouse, infectious disease epidemiologist at Edinburgh University, “Scientists are yet to find a single confirmed case of a teacher catching coronavirus from a pupil anywhere in the world.” Hopefully the data from his statement are forthcoming (https://www.thetimes.co.uk/article/school-closures-a-mistake-as-no-teachers-infected-in-classroom-gpppq8r7k).

Now FINALLY, thanks to everyone for keeping me up to date with the latest studies. And thank you for all of the personal messages. This post is still far from comprehensive and definitely not perfect. I would love to turn this into a peer reviewed article with other authors and reviewers helping me see beyond my own biases (we all have biases and that is why both team work and the peer review process are SO IMPORTANT in science; right now this is nothing more than a Facebook post and I am the first to admit it). If anyone is interested in working with the data here and anything else we can find for possible publication, please reach out.