Do COVID-19 Vaccines Cause Infertility?

Dr. Paul Offit explains why infertility is not a concern following COVID-19 or receipt of the COVID-19 mRNA vaccine.


Do COVID-19 vaccines cause infertility?

Paul Offit, MD: Hi, my name is Paul Offit from the Vaccine Education Center. One question that people have asked, and it’s actually very common actually that it's been asked is: Could SARS-CoV-2 vaccines affect fertility?

Well, first of all, in the United States, at least as of today, which is January 12th, 2021, that it’s listed that about 22 million people have been infected with SARS-CoV-2. That number is probably low, because when you look at that number, what that tells you are people who have been tested and been found to be positive for the virus. But a lot of people who have either asymptomatic infection or mildly symptomatic infection never got tested. So, the best way to tell really how many people have been infected in the United States is to do something called antibody surveillance studies, where you just look at large numbers of people and see whether they have antibodies to the virus, which then tells you that they've been infected. When you do those studies, you’ll find out that that 22 million number is probably off by a factor of three. It's probably closer to 66 to 70 million people, which is roughly 20% of the United States population.

So then the question is, if you know that 20% of the population has been infected with this virus, is there any evidence that we've had a decrease in fertility associated with this massive worldwide pandemic? And the answer is, no.

The second thing then is, could the vaccine do this? Could the vaccine cause infertility? Well, first of all, it's very hard for a vaccine to do something that natural infection doesn't do. When you're naturally infected with SARS-CoV-2 virus, that virus reproduces itself hundreds and hundreds and thousands and thousands of times. When you're given the SARS-CoV-2 vaccine, at least the mRNA vaccines, you're just given a messenger RNA which just codes for 1 of the 4 SARS-CoV-2 proteins, that spike protein, and it’s just all you do is make that protein; the virus doesn't reproduce itself. So again, it's very hard in nature to find that a vaccine does something that natural infection doesn't do, when natural infection is far harsher and far more likely to cause harm, obviously, than a vaccine.

I think a part of this comes from this sort of misperception that the SARS-CoV-2 protein, that spike protein, mimics a protein called syncytin-1, which is associated with placental physiology. But that's false. I don't know where that rumor started, but it's false; that's not true. There is no association between the SARS-CoV-2 spike protein and the so-called syncytin-1 protein. So, for so many reasons, there is no reason to believe that the SARS-CoV-2 virus or the SARS-CoV-2 vaccine will in any way affect fertility.

Thank you.

Related Centers and Programs: Vaccine Education Center

Last Reviewed on Feb 10, 2021