Do the COVID-19 vaccines cause infertility?
Check out this answer from Consensus:
The collective evidence from multiple studies indicates that COVID-19 vaccines do not adversely affect male or female fertility. Vaccination is safe for both men and women, including those undergoing fertility treatments and pregnant women. The benefits of vaccination, including the prevention of severe COVID-19 and the transfer of protective antibodies to the fetus, far outweigh any potential risks. Addressing misinformation and providing evidence-based information is crucial to combat vaccine hesitancy and ensure public health.
The COVID-19 pandemic has led to the rapid development and deployment of vaccines, which have been crucial in controlling the spread of the virus. However, concerns about potential adverse effects, including the impact on fertility, have contributed to vaccine hesitancy. This synthesis aims to evaluate the evidence regarding the impact of COVID-19 vaccines on male and female fertility.
Key Insights
- No Impact on Male Fertility:
- Multiple studies have found no significant changes in sperm parameters, such as sperm concentration, motility, and volume, before and after COVID-19 vaccination1 7 8.
- COVID-19 vaccines do not adversely affect male reproductive health or fertilization capacity in men undergoing assisted reproductive technology (ART) treatments8.
- No Impact on Female Fertility:
- Studies indicate that COVID-19 vaccines do not affect female fertility, including those undergoing in vitro fertilization (IVF) treatments. There were no significant differences in pregnancy rates, oocyte quality, or fertilization rates between vaccinated and unvaccinated women1 6.
- Vaccination does not lead to adverse pregnancy outcomes or affect the course of pregnancy and fetal development3 4 5 9.
- Safety in Pregnancy:
- COVID-19 vaccines, particularly mRNA vaccines, are safe for pregnant women and do not increase the risk of adverse pregnancy or neonatal outcomes. Vaccinated pregnant women showed similar rates of pregnancy loss, preterm birth, and neonatal health as those reported in pre-pandemic studies3 5 9.
- Vaccination during pregnancy is associated with the transfer of maternal antibodies to the fetus, providing additional protection against COVID-192 4.
- Misinformation and Vaccine Hesitancy:
Do the COVID-19 vaccines cause infertility?
Lee Riley MD has answered Extremely Unlikely
An expert from University of California, Berkeley in Infectious diseases, Epidemiology, Vaccinology
The currently approved Covid-19 vaccines cannot cause infertility. mRNA vaccines are comprised of synthetic pieces of RNA that rapidly get degraded at the site of injection after the RNA chain is translated into amino acids (building blocks of proteins). So there is no chance for the RNA to get anywhere else in the body for it to affect fertility. The vector-based vaccine like the newly-approved Johnson & Johnson vaccine uses another live virus (adenovirus) to deliver the Covid-19 coronavirus protein. The adenovirus that’s used in the vaccine will not cause infertility. People are exposed to all kinds of adenoviruses all the time, which cause no symptoms or common cold symptoms. Adenovirus 26 used in the J&J vaccine is not commonly found in humans and this is why it was used for making this vaccine. So, biologically, there is no possibility that these vaccines can cause infertility, and this is empirically supported by the fact that no adverse outcomes have been observed in vaccinated pregnant women.
Do the COVID-19 vaccines cause infertility?
Maciej Zatonski has answered Extremely Unlikely
An expert from GlaxoSmithKline in Vaccines, Vaccinology, Medicine, Otolaryngology, Public Health
No, they do not.
There is no evidence that any of the Covid-19 vaccines could cause infertility. There isn’t even a plausible biological mechanism in which this could happen. In fact, many participants of early clinical trials for Covid-19 vaccines later got pregnant and delivered healthy offspring.
Additionally, most of the Covid-19 vaccines can be used in pregnancy based on the appropriate risk:benefit assessment (i.e. when the prescribing physician decides that it is beneficial to the mother). Babies of mothers vaccinated for Covid-19 can be safely breastfed.
Covid-19 vaccines are relatively new, and were not yet deliberately studied in pregnant women; this lack of specific data means that manufacturers and regulatory bodies can not yet fully endorse the use of the vaccines in pregnant women. Such trials are currently ongoing (for example: https://clinicaltrials.gov/ct2/show/NCT04754594).
In available registries there are no cases of infertility caused by Covid-19 vaccines.
Do the COVID-19 vaccines cause infertility?
Rachel West has answered Extremely Unlikely
An expert from Johns Hopkins University in Microbiology, Infectious diseases
No, the COVID-19 vaccines do not cause infertility.
There is no evidence to suggest that the COVID-19 vaccines cause infertility, and plenty of evidence to support the safety of vaccines during pregnancy. Other vaccines to prevent diseases such as influenza and pertussis are important in keeping the pregnant person and the fetus safe.
Animal studies of the newest mRNA vaccine platforms show that there is no impact of vaccination on fertility. The vaccine platform used in the Janssen vaccine—an adenovirus vector, has been used by the company in past formulations with good safety profiles and the company is currently recruiting a trial for the vaccine in pregnant women.
It’s helpful to rely on what the evidence does show us. We do know that the COVID-19 vaccines are highly effective in preventing severe COVID-19 and deaths from the disease. This is particularly important for pregnant people, who are at increased risk of severe COVID-19 and complications. The American College of Obstetricians and Gynecologists recommends vaccination for pregnant people, as does the CDC.
We do need to keep monitoring vaccine safety, even after a vaccine’s release to the general public. Vaccine safety surveillance is so important because it helps us find even the rarest adverse events (side effects) of the vaccine, which may have been missed in clinical trials due to limited sample sizes. Safety surveillance includes tools like v-safe and VAERS.
It is important to note that our vaccine safety data in pregnant people is limited, as this group was excluded from initial COVID-19 vaccine clinical trials. Both Pfizer and Janssen have submitted protocols to study safety in pregnant women, and the data from these will also be helpful. Recent data from the v-safe program has demonstrated good vaccine safety in pregnant people, with more to come.
Do the COVID-19 vaccines cause infertility?
Zania Stamataki has answered Extremely Unlikely
An expert from University of Birmingham in Virology, Immunology, Vaccines, Hepatology
There is absolutely zero evidence or any legitimate scientific reason to believe that COVID-19 vaccines could cause infertility, you can rest assured. You are quite right to ask to reassure yourself and challenge misinformation.
Unfortunately this is one of the random myths that made the rounds on social media without having any scientific basis. This pandemic has seen a rise in disinformation and deliberate attempts to put people off life-saving vaccines.
The vaccines that have been approved so far have proven to be safe and you can take them without having any worries about affecting your fertility.
Do the COVID-19 vaccines cause infertility?
Taylor Pini has answered Extremely Unlikely
An expert from University of Sydney in Reproductive Biology
It is very unlikely, both theoretically and based on the lack of observed off-target impacts of the various COVID-19 commercial vaccines. There’s a lot of misinformation out there, which links back to some comments made about the similarity between a protein that’s part of the SARS-CoV-2 virus and a placenta protein called syncytin-1. These proteins may be similar, but they are not similar enough to cause problems with the maternal immune system targeting the placenta.
Do the COVID-19 vaccines cause infertility?
Quique Bassat has answered Extremely Unlikely
An expert from ISGlobal in Vaccines
No, they do not. Period.
Do the COVID-19 vaccines cause infertility?
William Hausdorff has answered Extremely Unlikely
An expert from PATH in Vaccines, Epidemiology, Infectious diseases
No, there is no credible evidence that COVID vaccines (or any other vaccines) cause infertility. When confronted with such huge allegations, I think it’s first useful to consider the provenance and the societal context. Are these “concerns” raised by a source that is generally considered scientifically credible? Conversely, are they associated with a source which may have a larger agenda about immunization or government in general?
Previous claims that various vaccines might lead to infertility have been linked to larger political concerns, sometimes associated with conspiracy theories (i.e., someone is trying to sterilize a certain population). For example, unfounded rumors that polio vaccines might cause infertility have arisen in the context of polio eradication campaigns in Nigeria and Pakistan. In both cases the rumors have dovetailed with regional discontent with unrelated economic policies by their respective federal governments (who are intrinsically tied to the eradication program). Similar rumors emerged a few years back for tetanus vaccine in Kenya, and this was subsequently attributed to lack of a consultation with important stakeholders prior to implementation of a vaccination program, rather than concerns about the vaccine itself.
There are some elements of the clinical trial design of COVID vaccines that may have unwittingly fed concerns about infertility (and birth defects). Pregnant women were excluded from being participants in all or almost all clinical trials to date. The exclusion was not based on any particular theoretical safety concern, but rather due to a superabundance of caution that is generally seen in vaccine trials. This has led to the unfortunate situation where there is a dearth of direct evidence of COVID vaccine reactogenicity in pregnant women in the context of a carefully monitored clinical study.
Without such evidence, definitive guidance is not forthcoming from public health officials, even though pregnancy has been associated with a higher risk of contracting COVID infection as well as more severe outcomes. Fortunately, there are increasing efforts to remove the presumptive ban on pregnant women in future vaccine studies, unless of course there are legitimate scientific concerns.
Do the COVID-19 vaccines cause infertility?
Catherine Thornton has answered Extremely Unlikely
An expert from Swansea University in Immunology, Reproductive Biology, Fertility
A lot of conspiracy theories and fake news surrounding the pandemic are doing the rounds. Among the disinformation is a suggestion that COVID-19 vaccines might cause infertility in women.
This seems to be based on perceived similarities between the coronavirus’s spike protein – which is the key part of the virus that the vaccines target – and a protein found in the placenta called syncytin-1. This has led to the unfounded theory that antibodies against the spike protein will attack syncytin-1, stopping it performing its important role in the placenta.
This is simply not true. The similarity between the proteins is insufficient for this to be of any concern.
All proteins are made up of long strings of individual building blocks called amino acids. SARS-CoV-2, the virus that causes COVID-19, is made up nearly 10,000 amino acids, of which around 1,300 are found in the spike protein. Syncytin-1 is made up of around 540 amino acids. Given that there are only 20 different types of amino acid, it isn’t surprising that many, many proteins share similarities.
To make a protein these long strings of amino acids are folded to form a 3D structure. For antibodies to mistakenly recognise syncytin-1 as SARS-CoV-2, there would have to be sufficient similarity of amino acids in these strings (which there isn’t) and the critical amino acids would need to be clustered together in the 3D molecule in a sufficiently similar and accessible way (which they aren’t).
No evidence of negative effects
Spike protein antibodies are made in response to both natural infections and vaccines. So women who have been infected naturally with SARS-CoV-2 during pregnancy also have antibodies to the spike protein. Therefore, studies of the natural immune response of pregnant women to SARS-CoV-2 – and the effects of infection on pregnancy outcomes – can provide insight into the risk of spike protein antibodies to pregnancy.
Evidence shows that the risk of miscarriage is not increased in women who have had a SARS-CoV-2 infection in early pregnancy. This indicates that even if spike protein antibodies are present within the uterus, they don’t have a negative effect on implantation or early development of the placenta.
The mother’s blood supply is not fully connected to the placenta until the end of the first trimester. The passage of antibodies from mother to baby across the placenta then follows in the second and third trimesters. This is a normal part of pregnancy and provides protection to the baby against infectious diseases. This is known as passive immunity and continues after the baby is born with antibodies being transferred via breast milk.
SARS-CoV-2 antibodies have been found in the newborns of women who have had COVID-19 during pregnancy and who continued to carry their pregnancy to term. (Typically, this is done by analysing umbilical cord blood collected when the baby is delivered.) This shows that antibodies are passing across the placenta from mother to baby and are not having a detrimental effect on the pregnancy. This is despite cells expressing syncytin-1 being the first point of contact on the placenta for these antibodies.
Exclusion from trials not unusual
At the outset of the pandemic there was much concern about the potential harmful effects of SARS-CoV-2 on pregnancy and unborn children. Pregnant women were included in lists of vulnerable people as a sensible precaution. This was based on experience with other viruses that cause more severe disease in pregnant women than the general population or can infect the placenta or the fetus and cause harm. This list of viruses includes influenza, hepatitis E, and Zika.
But the passage of time has shown us that we do not need to add SARS-CoV-2 to this list. Yes, pregnant women can develop severe COVID-19, which can increase the likelihood of being admitted to intensive care and giving birth preterm. Overall, however, pregnant women are less likely to experience symptoms of COVID-19 and are more likely to have milder symptoms when they do.
As a similar precaution, it’s normal practice to not include pregnant women in the testing of vaccines – or any other form of medicine – until their safety has been established. Given the short timescale over which COVID-19 vaccines have been developed, there simply hasn’t been the time to gather the safety data needed to confirm that it’s safe to enrol pregnant women in clinical trials.
While pregnant women haven’t been recruited into these trials yet, due to these trials’ large size, there have been instances when women involved have become pregnant. In the cases where this has happened, there has been no adverse effect on the pregnancy.
Likewise, there hasn’t been time to gather enough data to allow pregnant women to be included in the priority groups for vaccination. However, the safety data from the general population is sufficient for the Royal College of Obstetricians and Gynaecologists to advise that pregnant women who are clinically extremely vulnerable or frontline healthcare workers can consider being vaccinated and should discuss this with their doctor.
These women should not have any concerns that spike protein antibodies generated in response to the vaccine will have any harmful effects on their pregnancy.
I have adapted this answer from my original article in The Conversation