Will the COVID-19 vaccine affect male fertility?


Many men are wondering if the new COVID-19 vaccines are right for them, and whether they will affect male fertility. Here, we’ve gathered all the available data to help you make an informed decision. We will update this article as new research is completed.


How does the COVID-19 vaccine work?

The two COVID-19 vaccines currently approved for emergency use in the United States are both mRNA vaccines. That means that, instead of using a piece of dead or weakened virus to trigger an immune response—like a typical vaccine—the COVID-19 vaccines contain messenger RNA, a piece of genetic code that can be “read” by your cells.

Once the COVID-19 vaccine is injected, the mRNA instructs your cells to create a protein that’s a lookalike for the “spike protein” on the outside of the novel coronavirus, SARS-CoV-2. Though the spike protein is harmless, your immune system will identify it as a foreign body and produce antibodies to destroy it. Then, if you’re exposed to the coronavirus in the future, your immune system will have the “muscle memory” to quickly destroy the virus before it makes you sick.

The spike protein and the mRNA used in the vaccine are both destroyed soon after they’ve served their purpose. The amazing thing about mRNA vaccines is that they can create an immune response without having to actually inject the virus, or any piece of it, into your body—making them extremely safe and effective.


Will the COVID-19 vaccine affect male fertility?

To answer this question accurately, we need to divide the potential effects of the COVID-19 vaccine into short-term/temporary and long-term/permanent.


Short-term effects of the COVID-19 vaccine

There is the possibility of a short-term impact on sperm count after the COVID-19 vaccine. That’s because about 16% of vaccine recipients experience a brief fever—a side effect of the immune response that the vaccine is intended to create. We know from studies on influenza and other febrile (fever-causing) illnesses that a fever can cause a temporary drop in sperm production and increase in DNA fragmentation, so it’s entirely possible that the COVID-19 vaccine will have this effect as well.

However, this isn’t a cause for grave concern. Just as we would see with any other fever—caused by illness or vaccine—the drop in fertility will resolve within two months. As the American Society for Reproductive Medicine (ASRM) states, temporarily “diminished sperm parameters does not necessarily imply male infertility.”

Long-term impacts

Because these vaccines are new, we don’t have any data yet on their long-term effects on fertility. Thankfully, the way that mRNA vaccines work doesn’t raise any red flags for fertility and, in fact, may be protective—since we know that COVID-19 itself has some serious impacts on male fertility. (More on that below.)

The good news is that we’ll have much more information shortly. As soon as the vaccines were approved in the US, the CDC launched a complementary study examining the impact of vaccination on sperm concentration and motility (movement). The study, which should wrap up in June 2021, aims to provide an evidence base for the effects of COVID-19 vaccination on semen parameters, and to determine how long these possible changes may last following vaccination.


Will the COVID-19 vaccine change my sperm DNA?

No. The COVID-19 vaccines contain messenger RNA, which is physically and chemically different from DNA. DNA is two inter-coiled strands made up of four bases (the “double helix”), while RNA is a single strand made up of a different combination of bases. RNA’s function in the body is to carry instructions to create proteins, as it does in the case of this vaccine—it creates a lookalike for the COVID-19 “spike” protein. RNA does not change your cells’ genetic material, which is securely housed in the cell nucleus.

The synthetic messenger RNA in the vaccines does not enter the nucleus of your cells, nor is it possible for it to incorporate into your genome. Your cells break down and dispose of the RNA strand soon after it’s injected. So the mRNA vaccines will not impact the DNA inside your sperm, or DNA in any of the other cells in your body.

What can impact the DNA inside your sperm is illness, such as COVID-19 or influenza, along with smoking, chemical or toxin exposure, and paternal age. Damage to the DNA inside your sperm is known as sperm DNA fragmentation.



Should I get the COVID-19 vaccine if my partner and I are trying to conceive?

The Society for Male Reproduction and Urology (SMRU) and the Society for the Study of Male Reproduction (SSMR), two major male fertility medical organizations, are both recommending that the COVID-19 vaccine should be offered to men desiring fertility when they meet the criteria for vaccination. Similarly, ASRM has issued guidance that patients who are trying to conceive or going through fertility treatments should be encouraged to receive the vaccine.

One caveat: If you and your partner are undergoing fertility treatment, you may want to time your shots so that the potential impact of fever post-vaccination won’t affect your cycle. We recommend talking to your doctor about this.



Does COVID-19 affect male fertility?

All signs point to yes. COVID-19 has a significant impact on male fertility—at least temporarily. In one study, moderate cases of COVID-19 were associated with drops in average sperm concentrations by two-thirds compared to healthy men, and drops in average motility of one-half. Additionally, researchers from as Israeli medical center report that patients with moderate COVID-19 symptoms have a 50% reduction in semen volume, sperm concentration, and sperm motility 30 days post-diagnosis.

While we don’t have enough data yet to say if the effect is long-term, we do know that the coronavirus can infect the testicles, and that cases of orchitis—painful inflammation of the testes that can cause permanent fertility issues—have been identified among COVID patients.

So, it’s not inaccurate to say that the COVID-19 vaccine may actually protect against infertility by providing a high level of protection against COVID-19.



What can I do to protect my fertility? Should I freeze my sperm before getting the COVID-19 vaccination?

With a pandemic and brand new science on our doorstep, we’re certainly living in “uncertain times” (a phrase we’ve all heard probably a million times in the past year). One way to preserve your fertility in the face of uncertainty is to freeze your sperm.

Sperm freezing is a simple procedure, and the at-home kit offered by Legacy makes it even easier. Here’s what the process looks like for Legacy clients:

  1. Order a kit for delivery. Our For Tomorrow and Forever packages include sperm freezing, but For Today clients will also have the option to freeze after reviewing their results.
  2. Produce a semen sample via masturbation in the comfort of your own home. Then, mix the sample with the preservation media to keep it stable during shipping. Schedule a pick-up to transport the kit back to our lab.
  3. You’ll receive a comprehensive, clinic-grade report on your sperm health, including count, motility (movement), and morphology (shape). Learn more in our Guide to Sperm Testing.
  4. We also perform an important test called a “post-thaw analysis,” in which sperm is frozen, thawed, and evaluated to understand how many sperm cells survived and the motility of the sample after thawing.
  5. If your sperm passes the post-thaw analysis, you have the option to freeze it long-term. Once frozen, sperm can be stored indefinitely with no loss in quality. Thawed sperm can be used in an insemination or an IVF cycle.

Once you freeze your sperm, your fertility is protected against illnesses, accidents, the genetic risks of being an older father, and any other threat—even those we may not know about yet.

Learn more about sperm freezing.


  1. The Center for Disease Control. “Understanding mRNA COVID-19 vaccines.” 2020.
  2. Editorial Office, American Society for Reproductive Medicine. “COVID-19 vaccine and infertility: baseless claims and unfounded social media panic.” Fertility & Sterility, 2021.
  3. Society for Male Reproduction and Urology and the Society for the Study of Male Reproduction. “Joint Statement Regarding COVID-19 Vaccine in Men Desiring Fertility from the Society for Male Reproduction and Urology (SMRU) and the Society for the Study of Male Reproduction (SSMR).” 2021.
  4. Ranjith Ramasamy, MD. “COVID-19 Vaccine and Impact on Fertility Study.” Ongoing research, 2021.
  5. American Society for Reproductive Medicine Coronavirus/COVID-19 Task Force. “American Society for Reproductive Medicine (ASRM) Patient Management and Clinical Recommendations During the Coronavirus (COVID-19 Pandemic, Update No. 11: COVID-19 Vaccination.” 2020.
  6. Nora Holtmann, MD et al. “Assessment of SARS-CoV-2 in human semen—a cohort study.” Fertility & Sterility, 2020.
  7. Dan Aderka et al. “COVID-19 may harm sperm production.” Unpublished research reported via BioNews, 2020.
  8. Justin K. Achua et al. “Histopathology and Ultrastructural Findings of Fatal COVID-19 Infections on Testis.” World Journal of Men’s Health, 2020.
  9. Hassan Alkhatatbeh et al. “Does severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cause orchitis in patients with coronavirus disease 2019 (COVID-19)?” Arab Journal of Urology, 2020.