Why are some more likely to get Covid19?

Why are some asymptomatic while others suffer?

Why are kids so different than adults?

Short thread of new paper by @HarvardChanSPH colleagues, led by Kris Sarosiek (@CellDeathLab), first author @zintisinde
2/ For background, ACE2 is the receptor that SARS-CoV-2 uses to get into our cells

Questions they sought to answer: are there differences in ACE2 expression by age and does this correlates with disease severity?
3/ Here’s what they did:

They measured ACE2 expression in human lung tissue specimens from over 100 donors from ~4months to 75 years of age.

The full preprint is here, but come back to it. Keep reading thread to end.

4/ One (of many) finding that caught my eye:

"ACE2mRNA is expressed in the lung and trachea shortly after birth, *down regulated during childhood*, and again expressed at high levels in late adulthood"

Begins to explain the age-specific patterns of infection we see
5/ Plus this:

They found that regulation of cell death is different for children and adults

(Kris studies cell death, in case you didn’t get that from his twitter handle, @CellDeathLab)

What does this mean from a practical standpoint?
6/ It turns out that kids cells *commit to cell death much earlier after infection*, thus thwarting the virus’ attempt to hijack the cell and replicate.

It's a cell-f sacrifice (sorry...).

All normal, and the fancy word for it is apoptosis.
7/ The hypothesis here is that this self-sacrifice naturally curtails spread of virus. Needs to be proven, and more is coming

Major implications for repurposing existing drugs as therapeutics - might be able to kill off infected cells before the virus replicates uncontrollably
8/ Read Kris' thread here to learn more about the study, find out if I got this all correct, and ping him with questions

Follow him @CellDeathLab. Follow Zintis Inde @zintisinde

9/ Link to the preprint again

"Age-dependent regulation of SARS-CoV-2 cell entry genes and cell death programs correlates with COVID-19 disease severity"


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More from @j_g_allen

19 Sep
1/ Stay in your seat and remain calm.

This report is making the rounds.

I read it. (including appendix, which I'm guessing few read, b/c if you did....)

2/ For background, flight was from early March, 10-hour flight, thorough attempt to contact all passengers. A massive lift, so nice work by the authors on that front.
3/ Index patient had active symptoms, actively coughing, no masks

First takeaways:

-airplanes are vectors of disease, moving people around countries and globe and spreading
-this person was irresponsible

*stay home when sick*
Read 22 tweets
18 Sep
1/ Want to buy schools time? Open the windows

In late August, FAUCI answered a question on whether he supported healthy building strategies:

"You’re telling me we have this big crisis, and you’re telling me to open up a window? Yes, I’m telling you to open up the window.”
2/ Can it really be as easy as Fauci suggests? Just open the windows? Yes.
3/ When someone coughs, sneezes or just breathes, he or she releases viral particles suspended in respiratory droplets into the air, ranging in size from infinitesimally small to large droplets that will settle out of the air due to gravity.
Read 25 tweets
15 Sep
1/ The Lancet COVID19 Commission recognizes the role of aerosol transmission

In addition to role as a Commissioner, I am Chair of Task Force on Safe Work, Safe School, and Safe Travel

I added this section to our first statement, released today, and approved by all Commissioners
2/ Full text of section 15:

Identifying the dominant modes of COVID-19 transmission is an urgent public health priority. There is growing consensus from the aerosol science and infectious disease communities that aerosol inhalation is a key contributor to COVID-19 transmission.
3/ The US Centers for Disease Control and Prevention (CDC) and WHO have widely communicated a narrowed scope of possible transmission routes, limited to large droplets expelled by coughs and sneezes, and contact with contaminated surfaces.
Read 7 tweets
14 Sep
1/ Listen to the science and reopen schools

Adding months more to this toll will be an educational disaster that some children may never recover from

A thread...
2/ listen to the science, which says that schools can — and should — reopen for in-person learning with appropriate risk reduction strategies, while officials also implement aggressive steps to keep community transmission low.
3/ Listen to the American Academy of Pediatrics, which argued for focusing on science and not politics in supporting a return to in-person schooling with new investments in safety, describing in-person school as “fundamental” to the well-being of the nation’s children.
Read 29 tweets
13 Sep

âś…grocery stores
âś…Broadway theater
âś…jury trials

Thread pulling together our guidance since March

All avail at Harvard #HealthyBuildings: forhealth.org
2/ what to do in SCHOOLS

(w/ Harvard #HealthyBuildings team)

Read 15 tweets
8 Sep
1/ Sharing some example data on opening windows in schools (note the caveats/limitations on last slide)

If you're curious how we did this, we created a 'how to' that is available here: schools.forhealth.org

First, we need to start with the targets:
Read 13 tweets

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