Good morning, just a quick note from Dr Blair. I just wanted to address a few things that I have been hearing from people on social media about the vaccine and about Covid-19. Just as a reminder, I hold a PhD in microbiology, in virology, and I did my postdoctoral work in neuroscience at Penn. I did some epidemiology with WHO during the polio outbreak in the Dominican Republic, and I was a scientist for ten years. As such, I was a professor, so I profess. I am not a medical doctor, so I do not prescribe. I'm can tell you what I'm doing, but I cannot tell you what you should do.

If you have any questions about what's best for you, you should always go talk to your own a medical doctor who knows your history.

Also, I dictated this post and didn't have time to go through for typos. There are going to be some weird typos in it.

UPDATE: Dec 20, 2021 — More data in excellent journals support that SARS-CoV-2, aka “the Covid-19 virus,” infects testicles, causes “severe scrotal pain,” interferes with androgen/testosterone pathways, and causes male infertility. Updated link at the bottom. Yeah, everything in this post is correct. Covid-19 turns your jizz into fizz.

And now that all the disclaimers are out of the way, here we go.

One thing that I've been hearing that is really worrying is that some people, especially women, don't want to get the vaccine because they have heard that the vaccine can affect your future fertility. This is actually the opposite of what's true. (And to be clear, I have heard this from multiple people. If you've approached me and asked me this question, and several of you have, you're not alone, you are not even rare.)

What is true is that it is possible (and a few studies that have been done and what I would consider second-rate journals), that Covid-19 disease might cause sterility, especially in men.

Yes, you read that right, it is very possible that Covid-19 disease, but not the vaccine, might make guys shoot blanks.

Might make their swimmers into floaters.

Might make their spunk into junk.

It might also make their balls shrink.

Now, before you tell your husband go walk around without a mask as a method of birth control, let me stress that it is not guaranteed.

So, the proteins on the outside of cells that the virus latches onto in order to penetrate the cells is called ACE2. Your cells in your lungs and in your blood vessels have a lot of ACE2 proteins on them, and that's why it infects those structures.

The cells in the testes also express a lot of ACE2 proteins. There are papers published that show that men who have had moderate to severe Covid-19 disease have problems with the male hormones that they are producing, and those differences in the amount and concentration of the male hormones are often associated with sterility and “hypogonadism” (means “your balls shrink and die”). Other studies showed significant cell death of important cells in the testes.

Some studies of men with mild disease show these changes to a lesser extent, and any change in hormone levels is known to affect fertility in men.

I want to stress that none of these studies have yet been published in first-rate journals, which is where I normally get my information. Often, early studies are published in journals that are considered less good because you can publish in those journals with fewer results. This means that it is more likely that these papers are in error then if they were published in a top-tier journal like Nature, Science, or Cell, but there hasn't been enough time for any researcher to gather enough results to have a significant enough paper to publish in one of those journals.

What I'm saying is, this information is kind of from mid-tier news source. That means that it's not like it was published in the Washington Post, but it's not like it was published on Joe Schmoe, OD's blog, either. These are scientific journals with peer review. There's a better chance that they have found something that's true then it is a total error.

The vaccine has not been found to be associated with any loss of fertility, and so far, there is absolutely no hypothesized mechanism for it to do so. That means that leading scientists, the really good ones, have no information nor even theories about how the vaccine could impact future fertility. It won't. It really won't.

So, the Covid-19 vaccine (especially the Pfizer and Moderna ones, which are the ones I've looked at the most) is very probably completely safe for future fertility.

But Covid-19 disease is definitely impacting the organs and hormones associated with male fertility.

In addition, about twenty percent of men who get Covid-19 disease say that they have “significant scrotal pain.” (If that doesn't make a guy wear a mask, nothing will, amiright?) So, there are outward symptoms definitely associated with the disease that would suggest that the virus is infecting the testes in clinical disease and is causing this damage.

So far, there have been no studies that I have seen about the impact of Covid-19 disease in women's fertility, but the ACE2 protein that allows the virus to infect cells is expressed in women's reproductive tracts, too. This suggests that, as usual, scientists are studying men's health rather than women's health because institutional patriarchy.

So, the too-long-didn't-read summary is this: the vaccine will NOT cause fertility problems, but there is a growing body of research that getting the Covid-19 disease does.

ACE2R and COVID-19 Infection of Testicles

Updated Dec 2021 article SARS-CoV-2 and male infertility Nature Reviews (Excellent journal)