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 vaccine.


Do COVID-19 vaccines cause infertility?

Paul Offit, MD: Hi, my name is Paul Offit. It is Tuesday, May 4th, 2021. And I'm talking to you at the Vaccine Education Center at the Children's Hospital of Philadelphia. One question that has come up regarding COVID-19 vaccines, especially among young women of childbearing age, is, is it possible that this vaccine or these vaccines could affect fertility, could affect my ability to get pregnant?

The answer in short is, no. And let me explain why and where this whole false notion came from. This false notion was born of this letter that was actually written to the European Medicines Agency, which is like the European equivalent of the Food and Drug Administration, claiming that there was similarity between the SARS-CoV-2 spike protein, which is what you're making an antibody response to when you get these vaccines, and a protein that sits on the surface of placental cells called syncytin-1. So the thinking was, if you're making an antibody response to that spike protein of coronavirus, you're also inadvertently making an antibody response to this syncytin-1 protein on the surface of placental cells, which would then affect fertility.

First of all, that wasn't true. Those two proteins are very different. It's like saying you and I both have the same social security number because they both contain the number five. So that was wrong to begin with. Plus, you can argue there's two strong pieces of evidence that argue against it. One is that there was two prospective placebo-controlled trials done before submission for emergency use authorization from both Pfizer and Moderna. During those two trials, 36 women, roughly, became pregnant. Now, if it was true that this vaccine or these vaccines affected fertility, then there should have been more pregnancies in the placebo group than in the vaccine group, but that wasn't true. There were really 18 instances of pregnancy in the vaccine group and 18 instances of pregnancy in the placebo group. So, therefore, the vaccine didn't enhance fertility and it didn't negatively affect fertility.

Also, if you're arguing that antibodies directed against the SARS-CoV-2 spike protein would affect placental cells, remember that about a 100 million people have been infected with this virus over the past year and a half. During that time, they have been making antibodies to the SARS-CoV-2 spike protein. So, if it's true that that would affect fertility, then the question is, what's happened to the fertility rate or the birth rate right in this country, say between 2019 and 2020? If it was affecting fertility, if natural infection was affecting fertility, then birth rates should have gone down, but that's not what happened. Birth rates have actually gone up slightly. So, those are two pieces of evidence that argue against this vaccine or natural infection in any sense affecting fertility.

Thank you.

Related Centers and Programs: Vaccine Education Center

Last Reviewed on Jun 02, 2021