Ignore the anecdotes—there’s no proof the COVID vaccine causes infertility

When a heartbreaking miscarriage or stillbirth occurs shortly after a Covid vaccine, it’s easy to make a connection. But the science doesn’t hold up.

By Julian Daniel Sunday Willett
Ignore the anecdotes—there’s no proof the COVID vaccine causes infertility

Photo: iStock/Prostock-Studio

Misinformation about COVID-19 vaccines and fertility has propagated online despite the vaccines’ clear safety profile.

Fortunately, those considering having kids can relax when it comes to these crucial shots. These claims lack any realistic basis. As a medical doctor and a COVID-19 genetics researcher, I’d like to discuss what the evidence says.

Misinformation about fertility

Some sources of misinformation claim that the COVID-19 vaccines cause male sterility. For this to be true, the vaccines would have to damage sperm quality, drastically reduce sperm count or interfere with the mechanisms inherent in male ejaculation. Quality clinical evidence has demonstrated that none of these parameters are affected by the vaccine, so men are not being made sterile.

A study in Florida recruited around 45 men and compared their sperm measures before and after receiving a COVID-19 vaccine. Interestingly, the study found that men who received the vaccine had more sperm, greater semen volume, and sperm more able to move around and fertilize an egg.

Pregnancy can be an exciting time but can also provoke worry about the the safety of anything that enters the body, including vaccines. Fortunately, the COVID-19 vaccines are safe during pregnancy.

Sources of misinformation have claimed that COVID-19 vaccines can lead to loss of pregnancy, with vague references to antibody responses or other concepts that sound scientific. However, the COVID-19 vaccines will not make a pregnant woman any more likely to have a miscarriage.


A group of physicians spanning the United States studied the pregnancy outcomes for over 100,000 pregnancies. When the study was done, around 14 per cent of everyone investigated had received at least one dose of the COVID vaccine. They found that women who had the shot were no more likely to have a miscarriage than those who did not.

There are other misinformation claims along the lines of antibodies attacking the placenta, shots equating with infertility or interference with hormones. Unsurprisingly, all of these have been debunked.

The real danger is COVID-19 infection

While there is no evidence that the COVID-19 vaccine can impact fertility or pregnancy, there is evidence that a COVID-19 infection can cause harm. At its extreme, the disease can be fatal—an outcome that is more likely if COVID-19 infection happens during pregnancy.

Multiple studies have also documented an increased risk of miscarriage following a COVID-19 infection. However, miscarriage is not the only risk. The respiratory distress that can come with COVID-19, as well as the inflammation, can affect fetal growth, which could lead to health and developmental problems in a baby carried to term.

Carried to term is an important point here because pregnant women with COVID-19 are more likely to deliver their babies early. This is associated with health risks for the baby, including an increased risk of requiring intensive care.

The case for COVID-19 vaccination


It makes sense to get a COVID-19 vaccine. The risk of developing COVID-19 still exists and is still dangerous. This remains true while the case counts have trended downwards in North America to the tens of thousands from nearly one million a day in January.

A line graph showing decreasing COVID-19 cases since the end of December 2021 until March 19, 2022. As COVID-19 remains a danger, vaccination remains the best protection. Photo: Courtesy of Johns Hopkins University CSSE COVID-19 Data/CC BY

Fortunately, the vaccine offers excellent protection against developing an infection. It also dramatically decreases the chance of severe disease if infection does occur. When considering what poses the greatest danger to a pregnant woman or a couple looking to have children, severe illness poses the most significant risk of causing fertility or pregnancy problems.

COVID-19 misinformation is not going to go away. Previous vaccine misinformation has lingered despite a complete lack of evidence. For example, the myth of a vaccine-autism link was debunked in 1998, but vaccine hesitancy has persisted despite copious amounts of clinical evidence that these claims lack any sound basis. Articles like this one will not change some people’s minds, but ultimately that is not the goal.

The goal of sharing medical information from a physician’s point of view is to provide people with the knowledge that they need to make an informed health-care decision. While I strongly recommend the vaccine to everyone, individuals are the ones who choose what they seek to do with their bodies.

Public health can appropriately guide individuals towards making decisions in their and their community’s best interests, as with vaccine mandates. Individuals still maintain their autonomy, even if accompanied by consequences like employment issues. If one reflects on what is best for a baby, the evidence is clear. It is an individual’s prerogative on what to do with that information.

The Conversation

Julian Daniel Sunday Willett is a PhD Candidate in Quantitative Life Sciences at McGill University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This article was originally published on Mar 24, 2022

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