Thread by @VikiLovesFACS

A lot of people are asking me if #COVID19 mRNA #vaccines build up in the ovaries. This is an idea that seems to have come from some data submitted by Pfizer to the Japanese government.

But is it true? Let’s dive in!

(But TLDR: no...) 🧵

Here’s a machine-translated version of the document, so we can all see what’s going on. The document describes the outcome of two kinds of experiments. 2/

byrambridle.com/docs/bio-dist-…

First, they administered a version of the vaccine that encodes a glowing protein, luciferase, to mice. This allows us to see where the vaccine is making protein because… well... it glows! Please enjoy the glowing mice. 3/

You can see that they mainly glow at the injection site (on the hind leg) and, to begin with, in the liver. This is in line with similar experiments that have been conducted before, which you can find here… 4/

ncbi.nlm.nih.gov/pmc/articles/P…

And here… 5/

cell.com/action/showPdf…

Some people will be happy to look with their eyes and see that the signal is only significant at the injection site and liver, but for those who like graphs, @scientistabe has extrapolated individual organ data. You can see the ovaries aren't doing much. 6/

He explains how he’s done this here… 7/

https://twitter.com/scientistabe/status/1407717875767382019?s=20

So the mRNA in the vaccines is translated mainly at the injection site, but also a bit in the liver. So far, so much what we already know. 8/

But it’s the next experiment that seems to have got people interested in the ovaries. Here, they radiolabel the lipids (fats) that surround the mRNA in the nanoparticles and see where those fats end up if they inject them into rats. 9/

Note that when we find the fats, it doesn’t necessarily tell us that intact vaccine is there, it might just be broken down bits.

(But as we'll see, it's not going to matter that much...) 10/

This table tells us where the fats end up over the course of 48 hours. On the left, it tells us how many ug of fat is in each g of organ. I’m going to call that “parts per million”. On the right, it tells us what % of the total dose of fats ends up in each organ. 11/

Let’s plot these numbers! Looking at parts per million, we see a lot at the injection site, which is what we expect. Everything else (including the ovaries) is bumping along down at the axis. 12/

If we instead plot the % of injected dose, again we mainly see the injection site, as we expect. But this time we also see some in the liver. That makes sense, given the experiment looking at vaccine-encoded protein found a signal in the liver. 13/

And if you’re wondering why the concentration of lipids is low in the liver, and yet quite a lot of the total dose ends up in the liver… the liver is big, so a low concentration of lipids is still quite a lot of them! 14/

Again, we see all the other organs (including the ovaries) bumping along at the bottom, with not enough that we can really even see them. 15/

So why did people take this to mean that there is a lot of vaccine in the ovaries? Well, I have found some plots of this data which don’t include the injection site and liver. This makes a small increase in lipid in the ovary seem larger than it is. 16/

https://twitter.com/VeganBobCat/status/1404229685387481089?s=20

It's really a shame whoever made that first plot forgot to plot these, as it does rather change the meaning of the graph. 17/

Finally, how do the doses given to the rats in this study compare to those given to humans? Well… it’s about 1333x more (even before accounting for how rats and humans differ in their metabolism) 18/

(Thanks again to @scientistabe for maths!)

scientistabe.wordpress.com

So we can be confident that anything we’re seeing here, it’s actually going to be less in you and me, when we get our vaccines. And as we’ve seen, it’s not very much in the rats (or, for protein, the mice) to begin with. 19/19