Emily Oster

8 min Read Emily Oster

Emily Oster

How did COVID-19 Spread (or not) in Child Care and Schools?

Emily Oster

8 min Read

In this post, a summary of several studies on the spread of COVID-19 in child care and school environments. During the pandemic I spent considerable time collecting data on COVID in schools. These studies, however, come from other researchers.

Child Care Staff

As regular readers of this newsletter will know, this summer when I was collecting data on child care centers with my Google Forms, I talked up a study coming out of Yale on child care providers. It’s here! Or, at least the first paper is. It was published in Pediatrics. I contributed to a commentary on it, which was fun.

This paper focuses on risks to staff in child care settings; I assume there will be a follow-up on children, but given the much higher risk to staff, it’s really good to have started here. The Yale team collected data on about 57,000 child care providers early in the pandemic. They have data on whether the individual tested positive or were hospitalized with COVID (427 people) and whether they continued to see children in person. This last piece is really important because it allows them to have a control group: their main analysis compares people who continued to see kids in person to those who did not.

Their conclusion is that, in this sample, providers who see children in person are at no greater risk than those who did not (see below). There are COVID risks in both groups, but they are not higher in those who see kids.

Also informative in this study is the precautions taken. Not surprisingly, this was a fairly careful group. They report high rates of frequent hand washing and disinfecting toys, and about three-quarters are doing some kind of symptom screening or temperature checking. They did curbside pickup/drop off in nearly all cases to limit parent interaction. ( Masks were less common: only about 11% of kids and a third of staff).

As we titled our commentary: “Under the Right Conditions, Center-Based Child Care is an Unlikely COVID-19 Threat to Staff”.

Household Spread in India

I have been remiss in not discussing this paper from Science from late September on contact tracing in India. This is a really impressive effort to do comprehensive contact tracing in a low resource environment (two states in India) as well as look at infection and death rates.

The authors use evidence on 575,000 contacts of 84,000 cases, and they look at “secondary attack rate” — that is, the chance that each contact is infected by a case. In their data, this infection happens about 11% of the time for high risk contacts, and about 5% of the time for low risk. Being in a household together: about 9% transmission; health care setting, 1.2%; being in a car together for 6 hours, 80%.

The authors have some helpful graphs of transmission by age groups below, which basically finds that there seems to be a lot of transmission from very young kids to other very young kids. This got a lot of attention and you can see it in the data here. It’s definitely more concerning around child-to-child transmission, something we haven’t seen much of.

Caveats to this study include the fact that it is difficult for them to identify who is the index case; we saw results like this in South Korea for older children, and in that case it turned out that a lot of the transmission was actually simultaneous infection. These authors note that it is difficult to know whose infection was first. And from the standpoint of the US, the household and general environment in India is somewhat different.

Bottom Line: In this setting, we’re seeing evidence of more kid-to-kid transmission. Overall risk of infection from household contacts is about 10%.

School Reopening in Germany

Moving to older kids… One of the key school questions is whether kids will become infected at school and spread to the community. Will we see opening of schools drive community rates? I will say this has become a big question in the last week as many places have seen rates tick up and their schools are open. Of course, the general move together isn’t enough and this is begging for an analysis of community rates based on school reopen dates, but we do not yet have that in the US.

Where we do have that analysis, as of this week, is Germany.

The paper is here, entitled: School Re-Openings after Summer Breaks in Germany Did Not Increase SARS-CoV-2 Cases. The authors exploit the fact that German states differ in when they return to school after summer break. They are able to look at whether cases spike after school return. Basically, this is like asking: Georgia goes back to school in August, and Rhode Island not until September. Do we see spikes in Georgia in August and Rhode Island in September? This type of analysis is commonly called an “event study”.

Results are typically shown in graphs like the ones below (from their paper) which show the evolution of infection rates around school reopens. Basically, you can think of these as lining up all the German states so “time zero” is the date of school reopen, which differs by state, and then looking at how infections evolve in different age groups as time goes on. What is useful about having places with different start dates is the authors can control for general time effects.

Their bottom line, as suggested by the title, is that school reopening did not drive case rates. If anything, for kids aged 0 to 14 the rates actually seem to decline a bit after school reopens. They attribute this to the fact that there is more mixing and travel on summer break.

Notable here is that they see flat rates among adults. At least in this setting, the concern that kids are getting the virus, being asymptomatic and spreading it around at home does not seem to be valid.

Secondary Schools in Sweden

Finally, we have data from Sweden on infection around secondary school kids, parents and teachers. In case you haven’t been following: Sweden took a somewhat different approach from the rest of Europe and didn’t lock down very much. Many schools stayed open, and they generally kept restaurants and other businesses open. This has been criticized by many, an certainly their death rates early in the pandemic were far worse than comparable places in Europe.

The idea in this paper is to compare risks for teachers and parents of lower versus upper secondary school students. Lower secondary schools (think of this as the first part of high school) remained open. Upper secondary schools did not. (Primary schools and child care centers were open, and earlier data suggested limited risk to staff in those settings).

The authors find evidence that lower secondary school teachers are at higher risk than upper secondary school. That is: it would appear that being in person at work increased the risk of infection, both overall and serious illness. Parents of children in lower secondary school did not seem to be affected, but there is some evidence of effects for partners of teachers.

In terms of magnitudes, the authors estimate that 150 cases of COVID-19 would have been prevented if lower secondary schools had closed.

The authors put in a number of cautions — they do not know if teachers got COVID-19 at school or from kids, and it is notable that there were very few precautions taken. Schools were open at normal density, and masks are rare. But at a minimum this points to the need for precautions among staff in settings with older children.

(You might ask about student infections — they do not study them. Due in at least large part to very limited testing, there were only 87 confirmed cases of COVID-19 in students 7 to 16 in Sweden in this period, in a population of 1.2 million. This is too small a number to analyze).

Any Closing Thoughts?

This is a lot of new data. Most of it is reassuring, I think, especially on younger kids and especially the data from the US. But it also underscores the need for vigilance. The child care centers were sanitizing. Schools in Germany have some significant precautions (limited masks, though). Household transmission in India, where precautions are likely to be low and density high, is high among kids. Unmasked, fully dense secondary school does seem to increase infections among teachers.

What I am most encouraged by, I guess, is that we are starting to get these data in. I hope the next weeks will see more evidence of this type, and we can start to build a more coherent picture of what is safe and what is not.

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Do you brand things a certain way to get your kid to accept it? Like calling carrots “rabbit popsicles”? Or telling them to put on their “super speed socks” in the morning? Share your rebrands in the comments below! You never know who you might be helping out 👇

#emilyoster #funnytweets #relatabletweets #parentingjokes #kidssaythedarndestthings

Do you brand things a certain way to get your kid to accept it? Like calling carrots “rabbit popsicles”? Or telling them to put on their “super speed socks” in the morning? Share your rebrands in the comments below! You never know who you might be helping out 👇

#emilyoster #funnytweets #relatabletweets #parentingjokes #kidssaythedarndestthings
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Have you ever panic-googled a parenting question when everyone else is asleep? If so, you’re not alone. 

Today is the first episode of a new biweekly series on my podcast: Late-Night Panic Google. On these mini-episodes, you’ll hear from some familiar names about the questions keeping them up at night, and how data can help. First up: @claireholt!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #emilyoster #claireholt #parentingstruggles #parentingtips #latenightpanicgoogle

Have you ever panic-googled a parenting question when everyone else is asleep? If so, you’re not alone.

Today is the first episode of a new biweekly series on my podcast: Late-Night Panic Google. On these mini-episodes, you’ll hear from some familiar names about the questions keeping them up at night, and how data can help. First up: @claireholt!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #emilyoster #claireholt #parentingstruggles #parentingtips #latenightpanicgoogle
...

Sun safety is a must for all ages, especially babies! Here are my tips for keeping your littlest ones protected in the sunshine:
☀️ Most importantly, limit their time out in hot weather. (They get hotter than you do!)
☀️ Keep them in the shade as much as possible when you’re out.
☀️ Long-sleeve but lightweight clothing is your friend, especially on the beach, where even in the shade you can get sunlight reflecting off different surfaces.
☀️ If you want to add a little sunscreen on their hands and feet? Go for it! But be mindful as baby skin tends to more prone to irritation.

Comment “Link” for a DM to an article on the data around sun and heat exposure for babies.

#sunsafety #babysunscreen #babyhealth #parentdata #emilyoster

Sun safety is a must for all ages, especially babies! Here are my tips for keeping your littlest ones protected in the sunshine:
☀️ Most importantly, limit their time out in hot weather. (They get hotter than you do!)
☀️ Keep them in the shade as much as possible when you’re out.
☀️ Long-sleeve but lightweight clothing is your friend, especially on the beach, where even in the shade you can get sunlight reflecting off different surfaces.
☀️ If you want to add a little sunscreen on their hands and feet? Go for it! But be mindful as baby skin tends to more prone to irritation.

Comment “Link” for a DM to an article on the data around sun and heat exposure for babies.

#sunsafety #babysunscreen #babyhealth #parentdata #emilyoster
...

I’m calling on you today to share your story. I know that many of you have experienced complications during pregnancy, birth, or postpartum. It’s not something we want to talk about, but it’s important that we do. Not just for awareness, but to help people going through it feel a little less alone.

That’s why I’m asking you to post a story, photo, or reel this week with #MyUnexpectedStory and tag me. I’ll re-share as many as I can to amplify. Let’s fill our feeds with these important stories and lift each other up. Our voices can create change. And your story matters. 💙

#theunexpected #emilyoster #pregnancycomplications #pregnancystory

I’m calling on you today to share your story. I know that many of you have experienced complications during pregnancy, birth, or postpartum. It’s not something we want to talk about, but it’s important that we do. Not just for awareness, but to help people going through it feel a little less alone.

That’s why I’m asking you to post a story, photo, or reel this week with #MyUnexpectedStory and tag me. I’ll re-share as many as I can to amplify. Let’s fill our feeds with these important stories and lift each other up. Our voices can create change. And your story matters. 💙

#theunexpected #emilyoster #pregnancycomplications #pregnancystory
...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio!

OUT NOW: My new book “The Unexpected: Navigating Pregnancy During and After Complications” is available on April 30th. All of my other books came out of my own experiences. I wrote them to answer questions I had, as a pregnant woman and then as a new parent. “The Unexpected” is a book not to answer my own questions but to answer yours. Specifically, to answer the thousands of questions I’ve gotten over the past decade from people whose pregnancies were more complicated than they had expected. This is for you. 💛 Order now at my link in bio! ...

Is side sleeping important during pregnancy? Comment “Link” for a DM to an article on whether sleep position affects pregnancy outcomes.

Being pregnant makes you tired, and as time goes by, it gets increasingly hard to get comfortable. You were probably instructed to sleep on your side and not your back, but it turns out that advice is not based on very good data.

We now have much better data on this, and the bulk of the evidence seems to reject the link between sleep position and stillbirth or other negative outcomes. So go ahead and get some sleep however you are most comfortable. 💤

Sources:
📖 #ExpectingBetter pp. 160-163
📈 Robert M. Silver et al., “Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes,” Obstetrics and Gynecology 134, no. 4 (2019): 667–76. 

#emilyoster #pregnancy #pregnancytips #sleepingposition #pregnantlife

Is side sleeping important during pregnancy? Comment “Link” for a DM to an article on whether sleep position affects pregnancy outcomes.

Being pregnant makes you tired, and as time goes by, it gets increasingly hard to get comfortable. You were probably instructed to sleep on your side and not your back, but it turns out that advice is not based on very good data.

We now have much better data on this, and the bulk of the evidence seems to reject the link between sleep position and stillbirth or other negative outcomes. So go ahead and get some sleep however you are most comfortable. 💤

Sources:
📖 #ExpectingBetter pp. 160-163
📈 Robert M. Silver et al., “Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes,” Obstetrics and Gynecology 134, no. 4 (2019): 667–76.

#emilyoster #pregnancy #pregnancytips #sleepingposition #pregnantlife
...

My new book, “The Unexpected: Navigating Pregnancy During and After Complications” is available for preorder at the link in my bio!

I co-wrote #TheUnexpected with my friend and maternal fetal medicine specialist, Dr. Nathan Fox. The unfortunate reality is that about half of pregnancies include complications such as preeclampsia, miscarriage, preterm birth, and postpartum depression. Because these are things not talked about enough, it can not only be an isolating experience, but it can also make treatment harder to access.

The book lays out the data on recurrence and delves into treatment options shown to lower risk for these conditions in subsequent pregnancies. It also guides you through how to have productive conversations and make shared decisions with your doctor. I hope none of you need this book, but if you do, it’ll be here for you 💛

#pregnancy #pregnancycomplications #pregnancyjourney #preeclampsiaawareness #postpartumjourney #emilyoster

My new book, “The Unexpected: Navigating Pregnancy During and After Complications” is available for preorder at the link in my bio!

I co-wrote #TheUnexpected with my friend and maternal fetal medicine specialist, Dr. Nathan Fox. The unfortunate reality is that about half of pregnancies include complications such as preeclampsia, miscarriage, preterm birth, and postpartum depression. Because these are things not talked about enough, it can not only be an isolating experience, but it can also make treatment harder to access.

The book lays out the data on recurrence and delves into treatment options shown to lower risk for these conditions in subsequent pregnancies. It also guides you through how to have productive conversations and make shared decisions with your doctor. I hope none of you need this book, but if you do, it’ll be here for you 💛

#pregnancy #pregnancycomplications #pregnancyjourney #preeclampsiaawareness #postpartumjourney #emilyoster
...

We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy. 

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙

We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy.

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙
...

Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster

Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster
...

How many words should kids say — and when? Comment “Link” for a DM to an article about language development!

For this graph, researchers used a standardized measure of vocabulary size. Parents were given a survey and checked off all the words and sentences they have heard their child say.

They found that the average child—the 50th percentile line—at 24 months has about 300 words. A child at the 10th percentile—near the bottom of the distribution—has only about 50 words. On the other end, a child at the 90th percentile has close to 600 words. One main takeaway from these graphs is the explosion of language after fourteen or sixteen months. 

What’s valuable about this data is it can give us something beyond a general guideline about when to consider early intervention, and also provide reassurance that there is a significant range in this distribution at all young ages. 

#cribsheet #emilyoster #parentdata #languagedevelopment #firstwords

How many words should kids say — and when? Comment “Link” for a DM to an article about language development!

For this graph, researchers used a standardized measure of vocabulary size. Parents were given a survey and checked off all the words and sentences they have heard their child say.

They found that the average child—the 50th percentile line—at 24 months has about 300 words. A child at the 10th percentile—near the bottom of the distribution—has only about 50 words. On the other end, a child at the 90th percentile has close to 600 words. One main takeaway from these graphs is the explosion of language after fourteen or sixteen months.

What’s valuable about this data is it can give us something beyond a general guideline about when to consider early intervention, and also provide reassurance that there is a significant range in this distribution at all young ages.

#cribsheet #emilyoster #parentdata #languagedevelopment #firstwords
...