There is quite a bit of misinformation currently circulating on blogs, social media and various on-line platforms regarding the safety or lack thereof of the various Covid-19 vaccines and its potential impact on fertility.
The purpose of this communication is to address those concerns and to separate myth from fact and to remove the shroud of fog that has unfortunately collected over this important topic.
It should be noted that there are a myriad of worthwhile questions regarding Covid-19 including who should and should not be vaccinated, the long-term effects of the vaccine among many other topics. However, we will sharpen our focus and deal solely with the potential impact of the 2 currently available vaccines – namely the Pfizer and the Moderna products that have been approved by the FDA as an EUA– (Emergency Use Authorization) on human fertility and conception. The situation on the ground is that many women of childbearing age are either delaying vaccine administration due to fertility concerns or else foregoing it altogether. We wish to explore if this trend is based in fact.
In one of the very few peer-reviewed scientific articles addressing Covid-19 beliefs among a large population whichwas recently published in the Swiss Journal Vaccines, the authors determined that more than 25% of respondents firmly believed that the vaccines were designed to inject trackable microchips into recipients and furthermore, were believed to cause infertility. So, you may rightly ask, how is it possible, in today’s day and age, with near instantaneous access to all sortsof valid scientific information, that such a far-fetched idea would take root in one of every four individuals?
Furthermore, a nursing home facility in Ohio reported that 60% of staffers have declined their injections and decided to take a “wait and see” attitude. And these are health care professionalslooking after our most vulnerable populations!
It is important to understand the genesis of this discredited rumor, who perpetuated it and where it all began. First, there is the background of people who were already saying that Covid-19 was nothing more than a simple flu and/or was a conspiracy on the part of the pharmaceutical industry or the government. Against this backdrop of skepticism emerged a shadowy German epidemiologist/vaccine skeptic named Wolfgang Wodarg who, together with a former Pfizer employee, put in a petition to the European version of the FDA, the EMA (European Medicines Agency) requesting that they delay approval of the Pfizer/BioNTech vaccine. Their argument rested on the shaky and unproven hypothesis that the spike protein of the SARS CoV–2 virus and a protein necessary for placentation, syncytin-1, which is important in sustaining a pregnancy, shared a common sequence. They incorrectly hypothesized that when the Covid-19 vaccine produced an antibody against the actualvirus, that antibody would also be directed against the syncytin-1 protein, and pregnancies would be unable to be established. Of course, true to form, the anti-vaccination groups embraced this theory with glee and delight, and it soon made its rounds on anti-vaccination blogs, websites, and social media. Several platforms that policed content for authenticity removed these claims after it was found to be factually incorrect.
So, the question remains, is there any biological basis to this placental protein cross reactivity that the anti-vaxxers are proposing? Is there any scientific merit to their position? Is there any reason for women to avoid taking the vaccine for fear that they may not be able to have children? Or men for that matter? This is a very important question to address and we will look at the evidence.
First, let’s talk about the shared sequence between the spike protein on the surface of the SARS CoV-2 virus and the placental protein in question. Molecular biologists describe the similarity between them akin to two completely different phone numbers, but both happen to share a single digit. There would be no way to dial one number and reach both individuals. As anyone who has studied basic molecular biology knows, even one change in one base pair of a strand of DNA can have drastically different outcomes for that individual (think sickle cell anemia or cystic fibrosis) let alone a completely different sequence that happens to share one common base pair. So, scientifically, this theory does not hold water. In fact, the German scientist/anti-vaxxer himself stated in his petition that there is no actual scientific evidence that antibodies against the spike protein would also act against the placental proteins and in fact, is just a theory.
The other hypothesis circulating regarding a potential negative impact of the vaccines on fertility stem from the use of nanoparticle technology which is the delivery vehicle to supply the body’s cells with the actual mRNA vaccine. The nanoparticles used in both the Pfizer and Moderna vaccines are composed of an outer lipid shell which is impermeable to water and protects the RNA from being destroyed before it can reach the cells and initiate the antibody production process. An unfortunate post on Facebook claimed that these nanoparticles had the potential to harm both male and female infertility. However, the reality is that these nanoparticles are not new to the drug production industry and have been used for over 20 years in the routine delivery of a variety of pharmaceuticals with no discernable negative impact. The nanoparticles used in the delivery of most drugs as well as the current COVID-19vaccines are lipid nanoparticles whereas nanoparticles containing heavy metals such as silver or titanium were found to affect the fertility of laboratory animals but only when injected directly into their venous system, a very different particle and a very different entry method which cannot be extrapolated to the current Coronavirus vaccines.
Another related but debunked claim has been that the mRNA vaccines alter human DNA. This is not the case as mRNA never enters a cell’s nucleus, which houses our DNA and therefore cannot affect the genetic material of any individual. The mRNAremains in the cytoplasm and encourages a portion of the spike protein to be synthesized and thereby stimulates one’s immune system to create antibodies to fight this spike protein. This in turn, confers immunity to that individual.
Animal studies, which were conducted on both mice and macaque monkeys as part of the safety trials for the vaccinesand of course are not a substitute for actual human clinical trials but are a prerequisite for human trials to start, did not demonstrate any impact on fertility rates including litter size, weight of the pups or any other measurable parameter.
Now, how about data from actual individuals who have taken the vaccination and what has that information yielded in terms of fertility? So, the 37,000 test volunteers who were administered the vaccine during the clinical trials were requiredto be not pregnant as this was an exclusion criterion and was confirmed by negative pregnancy testing upon study entry. However, upon completion of the study after 2 rounds of the vaccination, apparently 23 women conceived, most likely unintentionally. It is instructive to note that of those 23 women who did become pregnant, 12 were in the vaccine group and 11 were in the placebo group, having received a sham injection. In addition, the only woman who suffered a pregnancy loss in the clinical trials of the vaccine was in the placebo group and did not receive the actual vaccine. In summary, among this very large and diverse group of study volunteers, there was no differences in fertility rates, albeit unplanned, between those that did and those that did not receive the vaccine series and the only miscarriage was in the unvaccinated group.
Furthermore, if you look at the estimated 70 million Americans who have been infected with the virus (approximately 20% of the total US population), one would have expected to see an epidemic of infertility if the placental protein theory were even remotely accurate, since the antibodies produced by natural immunity would likewise affect syncytin-1 as well as the vaccine created immunity. So, although the baseline infertile population of about 10-15% of couples still unfortunately continues, we have not seen an increase in these numbers of infertile women in the past year since Covid-19 was first took root in our communities. To summarize this point, experts state that if the actual virus and subsequent immune response does notseem to alter fertility rates, why would a narrower targeted vaccine be expected to do the same?
In addition, if the nanoparticle theory was accurate, then we would also expect to see a higher rate of fertility issues among those who have already been vaccinated in the trials and in the current round of vaccines, which of course has not happened.
So, the theories of the “placental protein” and the “nanoparticles” do not pass the test of what is known as “the law of biological plausibility” and are most likely not credible.
On the other hand, pregnancy itself is now considered a high-risk feature and women who conceive and then acquire the Covid-19 syndrome during pregnancy are more likely to develop a severe infection than non-pregnant women and are more likely to be hospitalized, more likely to require an ICU, and more likely to have a fatal outcome, again compared to non-pregnant women.
Researchers at the Yale University School of Medicine have analyzed antibodies in women who have been infected with Covid-19 and have found no evidence to support the placental protein theory and deemed it “exceedingly unlikely” that the vaccine would impact on fertility. They believe that a far greater concern is that women are having fear, anxiety and stress over the wisdom of vaccinating or not, especially when they are considering pregnancy. They concluded that women who are trying to conceive or who do wish to conceive in the future should want to get vaccinated, before pregnancy, for the health and safety of themselves and their future developing child. The group at Yale is joined by such prestigious organizations such the ASRM (American Society for Reproductive Medicine) ACOG (American College of Obstetricians and Gynecologists) and SMFM (Society for Maternal Fetal Medicine) all of whom assert that COVID-19 vaccines do not impact fertility and that “loss of fertility is scientifically unlikely”.
Of course, it is up to each woman, to gather the evidence and make up her own mind regarding the suitability and safety of the vaccine in her unique situation and if necessary, discuss any questions or concerns regarding vaccination with her trusted health provider in a shared decision-making process.
It is indeed sobering to consider, that as of today, nearly 450,000 Americans have succumbed to the Covid-19 virus and are sadly no longer with us. That sheer number should give us pause and allow us to calmly and rationally evaluated the best course of action for ourselves, our families, and our future families as well. But the science is solid and although further study is certainly required, the current evidence does not support any link between any of the current Covid-19 vaccines and the development of infertility.
Isaac Glatstein, MD, MSc is a Harvard-trained, Board-CertifiedReproductive Endocrinologist who specializes in Infertility, Assisted Reproduction, in vitro fertilization, recurrent pregnancy loss, Fertility Preservation, and minimally invasive uterine surgery. He graduated from NYU School of Medicine and completed his Residency training at the Mount Sinai Medical Center in NYC in Obstetrics and Gynecology and his Fellowship in Reproductive Endocrinology and Infertility at the Harvard Medical School/Brigham and Women’s Hospital in Boston. He was then awarded a prestigious Fulbright Research Fellowship to continue his research. He was a founding partner and an Associate Medical Director at Reproductive Science Center of New England as well as an Associate Medical Director at Boston IVF- one of the largest and most successful fertility practices in the country. He is the recipient of numerous honors and awards including Castle Connolly’s Top Doctor award, the Best of Boston Doctors award, and other accolades for research, teaching and patient care. In addition, Dr. Glatstein is one of a select group of fertility specialists who is also an expert in the laboratory side of IVF, having earned a Master’s degree with distinction in the Biotechnology of Human Reproduction and Embryology. His research was on the use of Artificial Intelligence in Embryo Selection to improve patient outcomes and pregnancy rates. He is currently working on developing a Center of Excellence for Reproductive Medicine in the area which will serve the Lakewood NJ and surrounding communities. His practice, Conceive NJ, is scheduled to open in the second half of 2021.