Thread by @InfectiousNeo

A lot of interest in what #COVID19 means for babies, and not a lot of data yet. Thanks to @EBNEO and their #COVIDneo hashtag to keep things organized! I wanted to briefly summarize what is known so far. 1/x

There are basically 4 considerations for infants:
1) Perinatal infection (at delivery/postpartum)
2) Late congenital infection (2nd/3rd trimester)
3) Early congenital infection (1st trimester)
4) Pregnancy disruption.

Let's take these one at a time... 2/x

Perinatal infection. At present, there is some light evidence for perinatal infection. There was an infant in China who tested positive at 34 hours, and another in the UK who tested positive "after delivery". I haven't heard the exact timing of that baby, if anyone knows! 3/x

Given the early antibody data, it looks like neutralizing antibody starts to show up in the first week and is close to 100% at 14 days. This means that there is a window (4-14 days before delivery??) where a mother can be infected but not pass on meaningful antibody. 4/x

This suggests that, like varicella, there is a theoretical "high risk" window for infection. Will be important to see if that plays out clinically.

BUT!!

All the evidence suggests that infants are asymptomatic or mildly symptomatic! So that's good... 5/x

We are testing at 48 hours even if asymptomatic with an NP swab. I would love to do more (AAP guidance suggests 24 and 48 hour NP, throat, and stool swabs) but I don't have access to that much testing, and I imagine most of us don't right now. 6/x

So perinatal infection = yes, almost certainly, but hopefully asymptomatic or mild. Still important to determine because has implications for transmission and maternal/infant separation. 7/x

Ok, how about late congenital infection with #COVID19?

Like SARS-CoV-1, SARS-CoV-2 RNA can be detected in blood. jamanetwork.com/journals/jama/…

This means that congenital infection is POSSIBLE. 8/x

However, we haven't seen it yet. I think there are close to 60 infants born to COVID19+ mothers in the literature so far, and that number will grow, but we haven't seen symptomatic COVID19 at birth yet. Two possible reasons... 9/x

One is that COVID19 might be terrible at navigating the placenta, making congenital infection really inefficient. If so, we will need a lot more infants born to #COVID19 mothers to see that signal... 10/x

...The other is that the "window" is so close to delivery that those infants are congenitally infected, but don't manifest symptoms until 5-14 days later, and so they look like they were infected perinatally instead of congenitally. 11/x

An early blood test (<24 hours?) could help, but NOT a priority right now.

Conclusion:
Late Congenital infection: No evidence yet, ?MAYBE? but unclear if it makes a clinical difference 12/x

Early congenital infection: This is one that worries me. Infection in the first trimester, especially during organogenesis, can be disruptive and totally unrelated to the pathogen's clinical features in the mom. See Rubella. 13/x

Is COVID19 going to look like influenza, where we don't see symptomatic congenital infection? Or is it going to look more like Rubella/CMV? Will need to wait 7-9 months to start getting those answers, unfortunately. SARS-CoV-1 did not cause disruptions, so 🤞🤞 14/x

Finally, pregnancy disruption. Even if nothing crosses the placenta, severe infections during pregnancy can cause preterm delivery, fetal distress, intrauterine growth restriction, and other complications. Malaria is an example (and can also rarely cause congenital dx). 15/x

So far, the data seems reassuring that pregnant women are NOT at increased risk for morbidity/mortality, so hopefully that continues. But the relative T cell dysfunction of pregnancy, and our experience with influenza, has us nervous. 16/x

Shout out to the #OBGYNs that are tackling this problem already. I am fortunate to work with @pramsey2012 and his team, who are very tuned in to perinatal ID. This data will come quickly in the next few months. 17/x

So:

1) Perinatal transmission - yes; unclear how severe
2) Late congenital infection - maybe, haven't seen yet
3) Early congenital infection - ??? data coming later
4) Pregnancy disruptions - ??? data coming soon

Hope this helps.
Stay safe out there everyone. #COVID19 18/Fin