As the pandemic rages on, Covid vaccine rollouts across the U.S. have brought waves of relief to millions—but the tide also has a dark side. Countless myths have surfaced regarding the vaccines' safety, especially when it comes to fertility.

And now that Pfizer's Covid vaccine has been authorized for use in kids ages 5 to 11, many parents are wondering whether getting the shot now will impact their child's future fertility. While it's understandable that parents may be worried about vaccine side effects in their kids (children aren't just tiny adults, after all), we have zero evidence that the mRNA technology used in the Pfizer vaccine affects fertility in any way.

But getting a severe case of Covid might. “There is evidence to suggest that infection with SARS-CoV-2 has the potential to impact both male fertility, female fertility, and certainly the health of a pregnancy of someone infected,” says Dr. Jennifer Kawwass, a reproductive endocrinologist and associate professor at the Emory University School of Medicine in Atlanta to NBC. “And there is simultaneously no evidence that the vaccine has any negative impact on male or female fertility.”

Vaccines in general have a long and storied history of being entwined with fertility fears—and the prevalence of social media has only added fuel to that fire, making false claims and misinformation about the Covid vaccine spread further, faster.

We're sharing the evidence-based answers that debunk the biggest myths out there. Here's what you need to know about the Covid vaccine and infertility.

MYTH: The mRNA Covid vaccines can change DNA, affecting your (or your child's) future fertility.

FACT: mRNA vaccines do not enter the nucleus of the cell, where DNA is contained.

The mRNA vaccines use messenger RNA to help your body's immune system defend against the virus. The vaccines instruct your cells to create a protein that's part of the SARS-CoV-2 coronavirus, which helps your body recognize and ward off the virus if you come into contact with it. But they don't have access to your DNA, which resides in the nucleus of the cell, say experts from Johns Hopkins, Lisa Maragakis, M.D., M.P.H., senior director of infection prevention, and Gabor Kelen, M.D., director of the Johns Hopkins Office of Critical Event Preparedness and Response.

The mRNA breaks down after it tells the cells to make the proteins to stimulate an immune response. Your DNA remains unaffected.

"Both the Pfizer-BioNtech and Moderna vaccines are not live virus vaccines. They do not enter the nucleus and cannot cause any genetic changes," ACOG's Vice President Dr. Christopher Zahn, MD, told Motherly. This type of vaccine technology has been in development for nearly two decades, which allowed for a quick response when the pandemic hit.


MYTH: The Covid vaccine harms the placenta in pregnancy.

FACT: The vaccine does not cause the body to attack the placenta.

When the vaccines were first made available, a false claim started making the rounds on social media that the vaccines instructed the body's immune system to create a spike protein that would attack another similarly shaped spike protein, syncitin-1, which is involved in the growth of the placenta during pregnancy.

"The two spike proteins are completely different and distinct, and getting the Covid-19 vaccine will not affect the fertility of women who are seeking to become pregnant, including through in vitro fertilization methods," write Dr. Maragakis and Dr. Kelen.

"During the Pfizer vaccine tests, 23 women volunteers involved in the study became pregnant, and the only one who suffered a pregnancy loss had not received the actual vaccine, but a placebo," write Dr. Maragakis and Dr. Kelen.

MYTH: The Covid vaccine lowers sperm count.

FACT: Studies have not shown that vaccines decrease sperm count.

A study published in JAMA found that there was no statistically significant decline in sperm count for men who received an mRNA vaccine. The study followed 45 healthy men with no prior fertility issues. Their sperm count was monitored before receiving their first dose of an mRNA vaccine, and again 70 days after receiving their second shot. Researchers found no decreases in sperm count among the study participants.

In fact, in several men, they noted an increased sperm count after vaccination—but this effect wasn't necessarily attributed to the vaccine.

"One of the biggest myths with the vaccine was that it could affect fertility," says Ranjith Ramasamy, director of reproductive urology at the University of Miami and one of the authors of the study. Finding no negative effect on sperm counts "was very reassuring," he told Scientific American.

MYTH: The Covid vaccine can cause miscarriage.

FACT: Several studies have shown that the vaccine doesn't raise miscarriage risk.

Three recent studies have shown that pregnant women who receive at least one dose of the Covid vaccines were no more likely to have a miscarriage than those who were unvaccinated.

A letter published in JAMA in September 2021 about one of the recent studies explained that of the 105,446 pregnancies analyzed, overall, miscarriages were no more likely within a month of vaccination than in the unvaccinated group, regardless of gestational age and vaccine type.

Another landmark study in the New England Journal of Medicine in June 2021 found that the miscarriage rate among those pregnant women who were vaccinated was within the range of expected miscarriage in the general population, at 12.5%.

MYTH: A vaccinated person can shed the virus onto a nearby unvaccinated person, causing illness or reproductive issues like irregular periods.

FACT: The Covid vaccines do not contain live—or even killed—forms of the virus, which means there's no virus to shed.

While "vaccine shedding" is a phenomenon that can happen with some vaccines containing weakened forms of live viruses (like in the chickenpox vaccine, though this still doesn't mean shedding will cause disease), the Covid-19 vaccines do not contain any form of the virus, which means there's no possible vaccine or virus shedding that can occur.

"None of the Covid-19 vaccines contain the live virus that causes Covid-19 so a COVID-19 vaccine cannot make anyone sick with Covid-19, including pregnant people or their babies," says the CDC.

In fact, the opposite is true: Being near someone who has been vaccinated actually provides protection against the virus, as the vaccine helps prevent the spread of disease.

MYTH: Antibodies from a Covid infection protect you just as well as the vaccine can from future infections.

FACT: Evidence shows getting a Covid vaccine is the best way to prevent future infection, regardless of having a previous infection.

While having recovered from a previous Covid infection confers some antibody protection, a study published in August 2021 shows that if you had Covid before and are not now vaccinated, your risk of getting a new Covid infection is more than two times higher than for those who were previously infected and then got vaccinated. That's a pretty serious risk to take on.

Experts don't know how long the immunity conferred from a previous infection will last—and it may vary from person to person. To reduce your risk of getting reinfected, vaccination is your safest bet.

Real risks to fertility exist from getting the Covid virus, not the vaccine

"There is currently no evidence that any vaccines, including Covid-19 vaccines, cause fertility problems in women or men," the CDC says.

However, very real risks to fertility do exist as a result of contracting the virus itself.

A meta-analysis protocol submitted to the British Medical Journal's BMJ Open in Feb. 2021 states that Covid infection may cause male infertility, as sperm are particularly susceptible to virus attack. The full report has yet to be published, but the researchers note in their initial submission that "some studies have shown that SARS-CoV-2 might affect female fertility and disturb female reproductive functions… Accumulating evidence now suggests that [Covid] may interfere with the female reproductive functions, leading to menstrual disorder, infertility and fetal distress."

The study's authors report that "Covid-19 is usually accompanied by high levels of interleukin (IL)-6, IL-8, tumor necrosis factor-α and other cytokines, which trigger a procoagulant state that is unfavorable to the development of blastocyst or fetus in a normal human uterus."

More research is needed in this area, but the current research that we do have makes a strong case for the benefits of vaccination over the risks of infection. If you still have concerns about infertility, be sure to talk to your doctor.

Sources:

Cavanaugh AM, Spicer KB, Thoroughman D, Glick C, Winter K. Reduced Risk of Reinfection with SARS-CoV-2 After COVID-19 Vaccination - Kentucky, May-June 2021MMWR Morb Mortal Wkly Rep. 2021;70(32):1081-1083. Published 2021 Aug 13. doi:10.15585/mmwr.mm7032e1

Johns Hopkins Medicine: Health. Covid-19 Vaccines: Myth vs. Fact. Updated Sept. 23, 2021.

Kharbanda EO, Haapala J, DeSilva M, et al. Spontaneous Abortion Following COVID-19 Vaccination During PregnancyJAMA. Published online September 08, 2021. doi:10.1001/jama.2021.15494

Li F, Lu H, Zhang Q, et al. Impact of COVID-19 on female fertility: a systematic review and meta-analysis protocolBMJ Open 2021;11:e045524. doi: 10.1136/bmjopen-2020-045524

Shimabukuro TT, Kim SY, Myers TR, Moro PL, Oduyebo T, Panagiotakopoulos L, Marquez PL, Olson CK, Liu R, Chang KT, Ellington SR. Preliminary findings of mRNA Covid-19 vaccine safety in pregnant personsNew England Journal of Medicine. 2021 Jun 17;384(24):2273-82.

A version of this story was originally published on Sept. 25. It has been updated.