Does the COVID-19 Vaccine Affect Kids' or Teens' Fertility?

The COVID-19 pandemic has been fretful for families. School closures, mask mandates, lockdowns, and the emotional turmoil of it all created a difficult environment to deal with—for parents and kids. The introduction of the COVID-19 vaccine from Pfizer, Moderna, and Johnson and Johnson was an incredible step in fighting the pandemic. However, since their introduction, information has been swirling about the possible side effects of the vaccines.

Now that children ages 5 to 11 are approved to get vaccinated, both the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) are urging parents to get their kids immunized. You may feel apprehensive about how this new vaccine might affect your child's health now and in the future, particularly if you've heard rumors about scary side effects, like the idea that the vaccine can impact your child's fertility.

The truth is, claims about the COVID-19 vaccine affecting fertility are completely false. "There is currently no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems in women or men," says Brian Levine, MD, MS, FACOG, a double board-certified OB/GYN and reproductive endocrinologist specializing in infertility, and member of the Verywell Family review board.

What are the Concerns About the COVID-19 Vaccine and Fertility?

Rumors about a connection between the COVID-19 vaccine and fertility began at the end of 2020 when a screenshot claiming that the head of Pfizer research said that the vaccine meant sterilization for women circulated on social media.

"Because topics related to reproductive health are incredibly emotional, false anti-vaccination claims have spread across the internet, and have deterred some of the most vulnerable populations from receiving the only effective tool in preventing the risk of infection from the virus that causes COVID-19," notes Dr. Levine.

It turned out that it was not the head of Pfizer who made the claim, and the claim is unfounded. The rumor was based on a statement that said the vaccine contains a spike protein called syncytin-1, which is essential for the creation of the placenta.

The vaccine works by training the body to attack the COVID-19 virus, and the concern was that the body would also be trained to attack syncytin-1. However, the COVID-19 vaccine does not contain syncytin-1, so this worry is moot.

"Given that there is no significant 'similarity in structure' between the spike protein and placental proteins, there is no risk of cross-reaction between antibodies against the spike protein and the placenta," explains Alan Copperman, MD, OBGYN, a reproductive endocrinologist specializing in infertility, the medical director at Progyny, and co-founder of Reproductive Medicine Associates of NY.

Does the Vaccine Affect the Hormones?

Reports of menstrual cycle changes after getting vaccinated have also fueled concerns about future infertility. Changes in the menstrual cycle generally indicate hormone fluctuations, so it is understandable to wonder about how fertility might be affected.

Hormones play a role in when menarche (first menstruation) occurs as well as how children grow and develop. Infertility is often linked to hormonal imbalance. Hearing the stories of people who experienced menstrual cycle changes after getting vaccinated may be concerning if you are deciding whether to immunize your children.

A research study found that about a fifth of women experienced menstrual cycle changes—heavier bleeding, lighter bleeding, or a longer duration of bleeding—after getting vaccinated. That being said, the changes were considered insignificant and lasted over the short term only. Short-term hormonal shifts that resolve themselves would not be a concern for future fertility.

The study also tested blood samples for sex hormones, finding no significant difference between those who had been vaccinated for COVID-19 and those who had not.

It could also be that the stress from the pandemic itself is affecting menstrual cycles, rather than the vaccine. "Personally, my period has been off since schools shut down back last March," says Jennifer Ellis, a mom of a newly-turned 5-year-old daughter who just got her first shot. "I think it'll finally settle down once [my daughter] Vera is fully vaccinated. I can't wait for her to get her second shot!"

Kids Should Get Vaccinated Against COVID-19

Children are less likely to contract COVID-19 than adults, and their illness is typically less severe when they do become infected. However, kids can still become seriously ill and require hospitalization in some cases. Kids can also spread COVID-19 to other, more vulnerable family and community members. "I don't see why anyone would want to leave the risk there by not vaccinating," says Ellis. "I would rather take all possible precautions, definitely including vaccination."

Getting kids vaccinated is an important part of fighting the virus so that we can return to a sense of safety and normalcy in our lives. The risks of getting COVID-19 overshadow any potential risks of getting vaccinated. Moreover, there is no evidence of a link between the vaccine and future fertility.

"The data we have collected and presented at international meetings agrees with emerging data from other centers, clearly demonstrating that sperm count, egg yield, and implantation and pregnancy rates are not compromised in vaccinated patients," emphasizes Dr. Copperman.