The Pfizer-BioNTech COVID-19 Shots Harm Sperm: Dr Byram Bridle

We covered jab/therapeutic effects on women’s menses

Now we’ll look at the harm to sperm

Substack of Dr Byram Bridle

Dr. Bridle is an Associate Professor of Viral Immunology in the Department of Pathobiology at the University of Guelph.

Isn’t it great that new harms keep popping up as research into the safety of the COVID-19 ‘vaccines’ uses data from the public rollout to compensate for what should have been assessed properly and thoroughly prior to or during clinical trials?

A peer-reviewed paper has just been accepted for publication in the journal Andrology. This journal has an impact factor of 3.842, which is quite good considering it has such a specialized focus. This falls into the category of what I like to call the ‘meat and potato’ journals; they publish good solid science. I like these kinds of journals because they tend to be influenced less by advertising dollars.

The paper that I am referring to can be found here.

I found this paper to be interesting. First, the authors are clearly ‘pro-narrative’; to a point where there is an awful lot of inappropriate rhetoric. Rhetoric has no place in an objective scientific article and this aspect of the paper should never have survived the review process. Regardless of the clear bias of the authors in favour of the COVID-19 inoculations, the results of their study are extremely concerning.

The authors rightfully criticized earlier studies that were being used to support the idea that COVID-19 inoculations have no negative impact on male fertility. All these previous studies had major flaws, including but not limited to:

  1. Testing only a single timepoint post-inoculation.
  2. Testing based on in vitro fertilization where there is a quality control step that eliminates low-quality sperm. One wouldn’t expect to find problems if only the best performing specimens are selected.
  3. Very small numbers of samples.

One of the things that I really liked about the current study is that it used serial samples from sperm donors. Specifically, samples were obtained prior to ‘vaccination’ and at multiple time points after the ‘vaccine’ regimen was completed. This means that each person served as their own internal control, which is ideal. The Pfizer-BioNTech product was used. The authors of the paper confirmed that none of the donors had been diagnosed with COVID-19. As such, any effects could be attributed to the vaccine, not the disease caused by SARS-CoV-2.

By approximately three months after becoming ‘fully vaccinated(i.e., defined as having received two doses), this is what the data demonstrated (confirmed to be significant by multiple different statistical tests):

  1. “sperm concentration was significantly lower”. Specifically, it was reduced by 15.4%. Put another way, the sperm concentration was reduced by 12 million/mL of ejaculate.
  2. Worse, there was a “[total motile count] percentage change reduction of 22.1%”. This translated into there being 31.2 million fewer motile spermatozoa per ejaculate.

Two rules of thumb when it comes to male fertility are:

  • The more sperm, the greater the chance of one of them getting into the egg.
  • Getting to and entering the egg requires the sperm to be mobile.

As such, the findings of this paper are quite concerning in the context of male fertility.

The data also demonstrated that these defects in semen appeared to be largely resolved by the mean long-term follow-up time of approximately six months. Interestingly, this led the authors to promote the shots because, although there is short-term damage to sperm, it looks like it resolves long-term, at which point a man would be ‘in the clear’.

Unfortunately, this study was performed when ‘fully vaxxed’ meant two shots. The authors assumed one would be finished getting jabbed at that point. Now, many countries have or soon will have re-defined fully ‘vaccinated’ to mean three shots. Further, four doses and beyond are being strongly encouraged.

So, how is a male going to recover from the so-called ‘transient’ damage to their sperm if they keep getting dosed before recovery can occur?

Worse, no studies have been done looking into the consequences on male fertility beyond two doses. What if it exacerbates the problem and/or extends the length of the problem?

Since sperm donors were used in this study, those from whom the semen was sourced would be considered particularly ‘robust studs’ among the male population. Their samples have to meet stringent quality control standards to become enrolled into a sperm donor program. This means there is the potential for greater harm to the semen of males among the general population whose fertility potential may not be as high.

But I Was Told that Pfizer Conducted a Reproductive Toxicity Study and Everything Looked OK

Indeed, Pfizer did run a pre-clinical reproductive toxicity study and they did conclude that their inoculations seemed to have no impact on fertility. However, here are two important facts that have not been widely disclosed by public health officials nor mainstream media:

  1. The COVID-19 inoculations are designed to get a person’s own cells to manufacture the spike protein from SARS-CoV-2. The pre-clinical safety study used rats. Human cells express what is known as a high-affinity version of the receptor for the spike protein. This means the spike protein from SARS-CoV-2 can bind strongly to human cells. In contrast, rat cells express the low-affinity version of the receptor. The spike protein of SARS-CoV-2 cannot grab onto rat cells very well. For example, rats that get infected with SARS-CoV-2 do not develop the disease we call COVID-19. It is a relatively simple task to ‘demonstrate the safety’ of a novel medical product if one conducts the safety testing in an animal model that can’t reveal toxicities.
  2. Remarkably, only the females were inoculated in the pre-clinical reproductive toxicity study. I’m not sure if Pfizer forgot that it takes ‘two to tango’ when it comes to reproduction. Regardless, in light of the newly released study discussed in this article, this omission becomes even more egregious.

Males in the General Population Are the ‘Guinea Pigs’ for Accurate Reproductive Safety Testing

So, like it or not, males of reproductive age participating in the public rollout of the Pfizer-BioNTech inoculation are the only source of reliable data to determine its safety (or lack thereof) in the context of fertility, especially for booster doses for which there isn’t a shred of reliable data publicly available.

Questions that Need to be Asked


  • How does it feel to know that the only reproductive toxicity study assessed by health regulators was fatally flawed and designed in a way that it could never address male fertility issues?
  • How does it feel to have had the Pfizer-BioNTech inoculation pushed so hard, to the point where it was mandated and people coerced into taking it only to learn now that it damages sperm?
  • How does it feel to know that your ability to conceive a child was likely compromised for months after inoculation?
  • How does it feel to know that your potential to conceive may never return to baseline as long as boosters are taken at short intervals?
  • How does it feel to know that the up-and-coming versions of the vaccines, with updated spike proteins, have not been required to undergo safety testing in the context of male fertility?


  • There is a dearth of properly conducted male reproductive safety studies. Data from the most comprehensive one to date (discussed here) demonstrates harm to sperm that they cannot recover from before boosters are recommended (five months later in North America). How confident are you in allowing your young, dependent son to receive these shots in light of their tiny risk from COVID-19 (and for the few who might be at risk, approved anti-viral treatments are readily available)?

People need to start directing these questions at their physicians and pharmacists (anyone administering these inoculations), public health officials, and politicians who think they are medical experts. Many of them are either unaware of important scientific nuances (like the fact that reproductive safety testing was done only for females in an inappropriate animal model) or know better but are afraid of retribution if they speak up. You must take responsibility for your own health and that of your family. Ask them to show you the studies that they are leaning on. If nothing else, that will prove that they have the relevant data in-hand. An inability to show you the objective science that forms their rationale should be a warning sign.

I learned the following from a friend of mine. It can help put things into a great perspective… People need to urgently draw a line in the sand if they haven’t done so already. You need to figure out for yourself how far is too far when it comes to pushing medical products that are associated with massive profits and control structures. Remember when it was ‘two weeks to flatten the curve’? That falsehood was enough for some to notice something wasn’t right. Many people have been OK right up to the point of being mandated two doses and even beyond. How many boosters are you going to allow? For two years we have taken such baby steps that many have not taken notice of how many promises have been broken. It becomes obvious when you have drawn your line. For me, my line is way behind where our society is at today.

More at the opening link

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