Emily Oster

5 min Read Emily Oster

Emily Oster

Viral Research Updates

Emily Oster

5 min Read

I hope you are all staying safe and doing something to protect your mental health.

It’s not an exaggeration to say this is among the most rapidly evolving data situations we’ve seen. We are learning more about the virus every day. Thank you to all of you who wrote in to suggest topics here. Let’s look at what we know now…

COVID-19 and Kids: New Data

There is new data out of China on pediatric cases. It’s simple summary stats: they had 2143 cases, of which 731 were lab-confirmed and the rest were suspected. Note that some of the latter may have been flu or other.

Cases were classified as asymptomatic (no symptoms), mild (cold symptoms, may or may not have fever), moderate (fever and cough but no shortness of breath), severe (disease progresses, low oxygen saturation, needs significant medical care), critical (other organs involved, acute respiratory distress).

The graph below shows the share in each of these groups for all cases and the sub-samples of infants less than 1 year, and lab-confirmed cases. Not noted here is one death in the data, a 14 year old boy.

Most cases – about 94% of all cases, 90% of infants, 97% of confirmed cases are asymptomatic, mild or moderate. The majority of these are asymptomatic or mild. Some children, more infants than others, did get very sick. But this is a small share.

Are these data relevant for the US? I see no reason why they wouldn’t be. If anything, I think we’d expect the situation in the US to be better – we have (broadly) better functioning health care and with lower pollution and less smoking kids and everyone are likely to be less susceptible to respiratory illness.

Overall, I read this as at least somewhat reassuring, although I know others may not (the NY Times headline noted that this says that kids can get very sick; this is true). The vast majority of kids who are infected will not be seriously ill. This doesn’t mean the virus isn’t scary – it is, I think we are all pretty scared at this point – but it may help with some perspective.

COVID-19 and Birth: New Guidelines

No new data here, but the Lancet published new guidelines for childbirth around the pandemic. Note that these are largely based on the 9-patient case series from China that I covered in the last newsletter so it’s not an overwhelmingly sized dataset.

These focus on what to do when doctors suspect (or know) the mother is positive at the time of childbirth or shortly before or after. In bullets…

  • There’s no evidence of vertical transmission (that is, if mom has it she doesn’t pass to the baby in utero or through delayed cord cutting).
  • There remain concerns that an infected mom could pass the disease to the baby after birth (i.e. through breathing, handling, etc). They suggest hospitals consider separation of mom and baby in this case, as is done for flu. They say consider; some hospitals may mandate.
  • Sick infants should be treated (obviously)
  • The virus was not detected in milk, meaning breastfeeding is not counter-indicated. However, again mom should try to be careful around the baby. If they are separated, mom should pump.

COVID-19 and Birth: Notes from the Trenches…

After my last newsletter, a number of people wrote in from heavily affected areas to note changes they were seeing on the ground. In particular, in both San Francisco and NY at least some low-risk women in late pregnancy are being told to skip prenatal appointments or do them over the phone and to “come in when you are in labor.”

In addition, they reported some hospitals are restricting the number of support people to one (i.e. just your partner if you have one) or even none.

All of these seem to be heavily location and hospital dependent. And they are evolving. My medical editor for Cribsheet, Adam Davis, wrote from San Francisco to say he thought it was possible some women might be pushed towards home birth if things get overwhelmed. So far, we haven’t seen that happen.

…and a correction

Finally: a number of thoughtful readers pointed out my 50% number for home birth hospital transfer was too high. I agree. In Expecting Better I cite 30% for first time moms, much lower for second time moms. Mea Culpa. I stand by the view that planning a home birth at the last minute is a mistake.

COVID-19: What Data do we Need?

As someone whose academic work touches on epidemiology and statistics, I cannot help but comment here on what data we need. In my view the biggest hole is testing data. At the moment we have no idea how many people are infected without knowing it. This is hugely important for understanding the fatality rate and for understanding how infectious it is. We need more testing of everyone, including people who are not very sick.

One town in Italy did this systematically, and apparently most NBA teams seem to be able to do it, but that’s not a random population.

WE NEED MORE TESTING. Period.

Community Guidelines