Despite the overwhelming scientific evidence indicating the safety and effectiveness
of Covid vaccines, some people are still nervous about being vaccinated. In addition,
there are people who want to stop others from getting covid vaccines by lying,
putting out misinformation or distorting known facts. As a result, fertility specialists across
the world have been getting questions from women who have heard that covid vaccines may make them
permanently sterile. Today, I am going to release the results of InfertilityTV original research
conducted right here at IVF1 on the effects of Covid and Covid vaccinations on female fertility.
To understand this research, I really need to
first discuss the misinformation that has been circulating on social media
and some background information about covid vaccines and infertility. If you
want to skip to the study results, just click the Study Results chapter in the description.
This study was conducted at my practice, IVF1, which is located at the Naperville Fertility
Center in the United States. The study ran from January 2021 through now. During this time frame,
two Covid vaccines were available. The vaccine from BioNTech / Pfizer and the vaccine from
Moderna. Both are RNA vaccines. This means that instead of injecting the virus or virus parts into
a person, we are injecting a small molecule, RNA, which instructs some of your cells to
make a virus part called the Spike Protein. The spike protein is what enables the virus to enter
your cells. When your body detects this foreign protein, it starts to make antibodies against it.
Some of these antibodies against the spike protein will block the virus from entering your cells.
These are called neutralizing antibodies. Neutralizing antibodies protect us from
getting an infection and before you know it we are going to restaurants and movie theaters again.
Could this process of vaccination and antibody formation cause a woman to
become permanently infertile? First, a little background...
After fertilization, the embryo starts dividing. By 5-6 days later, a normally developing embryo
will have divided into over a hundred cells and is called a blastocyst. The blastocyst has two types
of cells. One group of cells, called the inner cell mass, goes on to form the fetus. The much
larger group of cells called the trophoblast goes on to form the placenta. When the blastocyst
embryo implants, the trophoblast cells burrow their way into the uterine lining.
This process requires that some of the trophoblast cells keep dividing and that some of them fuse
together. The ones that keep dividing are called cytotrophoblast. The ones that fuse together
are called syncytiotrophoblast. Both types are essential for normal placental function.
There is a protein in these placental cells called syncytin-1. Studies have
shown that syncytin-1 is critical in the formation of the syncytriotrophoblast,
and is also responsible for establishing blood circulation from the mother
to the placenta. This allows the delivery of oxygen and nutrients to the fetus
The biggest concern created by the misinformation about covid vaccines
is that they could cause infertility by directing the immune system to mistakenly attack syncytin-1
which would prevent the embryo from implanting in the uterus. This would be very concerning
since once the immune system was primed to recognize and destroy, it would be difficult
or impossible to stop it. Every time an embryo tried to implant for the rest of a woman’s life,
her immune system would attack and prevent it from implanting causing permanent sterility.
Does this make any sense? In a word? No
First, this theory relies on syncytin-1 being similar in structure to the spike protein. Which
it is not. Proteins are made up of a specific sequence of amino acids. Syncitin-1 is 538 amino
acids long. The SARS CoV-2 spike protein is 9,860 amino acids long. That means the spike protein is
over 18 times bigger than syncytin 1. That would be like confusing an elephant with a puppy.
More importantly, the longest similar sequence of amino acids between the two proteins
is 4 amino acids long. That amount of similarity is far, far too low to confuse your immune system
Second, a team from the Yale University School of Medicine, led by immunologist Akiko Iwasaki,
looked at the reactivity of 3,000 different proteins in humans to the antibodies formed
as a result of a natural covid infection or covid vaccination.
For syncytin-1, they found no reactivity. This means that the antibodies from covid
infections or covid vaccines do not get confused and do not attack syncytin-1.
Third, the companies who make the vaccines also did
animal safety studies. In the data they reported to the US FDA,
when the vaccine was given to animals prior to mating and during gestation it was
NOT found to have any adverse effects on female reproduction or fetal or embryo development.
Okay, we have laboratory studies and animal studies, but there haven't been
any clinical studies looking at the impact of the vaccines in human women...until now.
Our study looked at women who were attempting to conceive with IVF.
Top IVF programs now commonly perform IVF in two phases. In the first phase, embryos are
created in the IVF laboratory and then frozen. In the second phase, an embryo is thawed and
placed into the patient’s already prepared uterus. This is known as a frozen embryo transfer or FET.
Using frozen embryo transfer is a great model to study the impact of various factors on
implantation since it bypasses many of the variables that normally impact a woman's
ability to get pregnant such as ovulation, fertilization and early embryo development.
With an FET, we know that every woman studied had a well developed embryo placed in the uterus.
Our study looked at whether the pregnancy rates were any different
between women who received the Covid vaccine and those that didn’t.
We could also look at the impact of a previous Covid infection. Here is how the study worked.
At the beginning of every treatment,
all of our FET patients have a baseline blood test and ultrasound.
One of the blood tests we started doing in January was to look for Covid antibodies in the blood.
For this, we used the Elecsys Anti-SARS-CoV-2 assay from Roche Diagnostics. The is a highly
selective test which identifies antibodies to the spike protein only. The antibodies could
be from vaccination or from previous infection so when we found a patient who had covid antibodies,
we contacted them to find out if they had received one of the vaccines or had been sick with Covid
or had a positive nasal swab for Covid in the past. Those women who did not have vaccination
or known previous illness were presumed to have had a previous asymptomatic infection.
The occurrence of a pregnancy was determined with a blood test. The embryo trophoblast
cells produce the hormone hCG. After the embryo implants and establishes a connection
to the mother’s blood supply, the hCG can be detected by doing a blood test on the mother.
Since implantation occurs two to three days after the embryo is placed in the uterus,
our patients returned 8 days after the embryo transfer to have this blood test. A positive
result indicates that the embryo’s trophoblast was able to produce hCG, implant in the uterine lining
and continue to develop sufficiently to allow a connection to the mother’s circulation.
These last two steps rely on the syncytin-1 protein. If the mother’s immune system attacked
the syncytin-1 protein and therefore damaged or destroyed the placenta,
she would not become pregnant and therefore have a negative hCG pregnancy test.
The pregnancy rate was calculated by dividing the number of women with a positive test
by the total number of women who had an embryo transfer.
So what did our results show? The pregnancy rate for women who had vaccination compared to those
who didn't was statistically no different. About 70 to 75% of the women who had an embryo transfer
became pregnant. By the way, these ranges are called confidence intervals. This is a statistical
tool. They tell us that we can be 95% certain that the “true” pregnancy rate is somewhere in that
range - just in case our pregnancy rates might be skewed by having low numbers. Because the ranges
between the groups overlap, we can be very sure that there is no difference between the groups.
What about women who had antibodies because of a previous infection with covid? Turns out their
pregnancy rates are also in the same range as vaccinated women and women without antibodies.
Finally, since the Roche assay gives us a numeric antibody level,
we compared those women with the highest antibody titers
to women without antibodies and still found no difference in the pregnancy rates.
After a positive pregnancy test, some women may go on to have a miscarriage. We next wanted to
see if maybe the immune system is damaging the placenta after the embryo implanted. If a woman
had a positive pregnancy test, we brought them in a few weeks later for early pregnancy ultrasounds.
With a viable pregnancy, we first expect to see a fluid filled sac in the uterus
and about a week later, we expect to see an early developing fetus with fluttering motion
in the tubes that eventually become the heart. We found no difference in the miscarriage rate
after the blood test until the first ultrasound or between the first and second ultrasounds.
Our InfertilityTV bottom line is this. There is no biologically plausible reason to believe that
Covid vaccines would cause a woman to become infertile. Laboratory studies, animal studies and
now real world human studies all refute the idea that covid vaccines cause infertility. Our data
also does not support an increased risk of miscarriage. So roll up your sleeves, get that
vaccine as soon as you are able. I would really like to see Marvel’s Black Widow in an actual
movie theater. Hopefully, we will finally find out how Natasha Rominoff was forcibly sterilized
during her training to be a master assassin. At least we know they didn't use a covid vaccine.