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5 Things to Know about the COVID-19 Vaccine, Fertility and Sexual Functioning

By Dr. Kristina Adams Waldorf, Sara Rutz, Isabelle Crary and Carly Baxter

With the introduction of the COVID-19 vaccine there has been a lot of information going around on its safety, especially when it comes to fertility. It can get confusing when you read multiple sources on the topic and get conflicting answers. Many wonder: should I be concerned about my future fertility following vaccination? 
Below we have 5 key things to know about COVID-19 vaccine and fertility based on the latest research.

1. The COVID-19 vaccine does not affect the ability to become pregnant
Many individuals have voiced concerns about the effects of the COVID-19 vaccine on current or future pregnancy. However, data has shown that there is no association between receipt of the COVID-19 vaccine and fertility, in fact, studies indicate that pregnancy success rates in people with the COVID-19 vaccination are equivalent to unvaccinated individuals. 

2. Antibodies created by the COVID-19 vaccination will not attack placental proteins
Claims have circulated among many social media users that the antibodies formed after receiving the COVID-19 vaccination can cross-react with placental proteins and thus affect future fertility. There is no evidence to support this claim and it has been shown that the spike protein and the placental protein in question (syncytin-1) are not similar at all, in fact, in total they share less than 7% of the same amino acid sequence. Dr. Akiko Iwasaki’s laboratory from Yale University examined the reactivity of thousands of different proteins in humans to the antibodies formed as a result of a natural SARS-CoV-2 infection or COVID-19 vaccination. There was no reactivity to syncytin-1, the placental protein in question..However, when pregnant people become ill with the COVID-19 disease, the infection itself can damage the placenta. In a study of 1.3 million U.S. pregnancies, pregnant people with a COVID-19 infection had a 2-4 times higher risk of stillbirth than uninfected women, with the highest risk occurring during the Delta variant wave (July-September 2021). High levels of virus have also been found in a stillborn fetus in several cases after the mother had COVID-19.

3. The COVID-19 vaccine does not lower sperm counts or decrease male fertility. 
Studies have shown that COVID-19 vaccination is not harmful for the production of sperm.  In fact, one study showed that some people with low sperm counts before receiving the vaccine had higher numbers after vaccination. That may be a coincidence, but this study shows that the vaccine is at least not harmful for sperm production. However, COVID-19 disease can reduce sperm motility. COVID-19 disease can also cause painful inflammation and swelling of the testes and the vaccine reduces the likelihood that this will occur.

4. The concern with COVID-19 disease and males sexual functioning is real. 
There are many reports and studies of men losing their ability to have an erection after COVID-19 disease, which may be due to blood vessel damage, lower testosterone and/or psychological distress. How frequently this might occur is unknown. Here are a few other studies investigating erectile dysfunction in men after COVID-19 disease. 

5. The COVID-19 vaccine may change the length of a woman’s menstrual cycle, but it is such a small change she may not notice. A study recently reported that the COVID-19 vaccine may result in a temporary less than one day change in the length of the menstrual cycle (on average 28 days), with no change in how long the period lasts. This difference was not considered to be clinically meaningful and women do not have changes in fertility as a result of this less than one day change in the menstrual cycle.

Meet the Authors

Kristina Adams Waldorf, MD

Kristina Adams Waldorf, MD is a Professor of Obstetrics and Gynecology and Adjunct Professor of Global Health at the University of Washington School of Medicine. She is an internationally recognized expert in how infections impact pregnancy and how vaccines and therapeutics protect the mother and fetus. She is Chair of the National Institutes of Health Obstetrics and Maternal-Fetal Biology Study Section. She is a member of the Center for Reproductive Sciences and the Center for Innate Immunity and Immune Diseases. Her grant support has come from the National Institutes of Health, the March of Dimes, Burroughs-Wellcome Fund, the Canadian Institute for Health Research and the Australian National Medical Research Council.

Sara Rutz

Sara Rutz graduated from the University of Alaska, Anchorage with a Bachelor of Science degree in Natural Sciences and a minor in Psychology. She is now a third year medical student at the University of Washington School of Medicine. Prior to medical school, she worked with diverse & underserved populations in patient care settings and as an insurance specialist for 5 years. She has been involved in research on improving outcomes for infants with Neonatal Opioid Withdrawal Syndrome, quality improvement in obstetric care, and providing up to date information as a volunteer for the COVID-19 Literature Surveillance Team. She is passionate about reproductive medicine and improving access to care for rural and underserved populations.

Carly Baxter

Carly Baxter graduated from the University of Puget Sound with a Bachelor of Science degree in Biology and a minor in French studies. She is now a 2nd year medical student at the University of Washington School of Medicine. She has worked with the MaMHA (Maternal Mental Health Access) group coordinated by the University of Washington and WA Department of Health in an effort to reduce maternal mortality rates in WA state. She is passionate about reproductive justice, equitable health care access and volunteering within her community at local health fairs.

Isabelle Crary

Isabelle Crary graduated from Stanford University with a Bachelors of Arts in Human Biology. She is now a second year medical student at the University of Washington. She has been involved in research on anemia in pregnancy, breast cancer prevention and treatment, and adolescent nutrition. She is passionate about healthcare for individuals who are pregnant, reproductive justice and nutrition education.