Can the COVID vaccine lower your sperm count?

Is sperm count affected by the COVID vaccines?
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Some of the most common myths involving the COVID-19 vaccines revolve around infertility and pregnancy risks in women. These myths have largely been debunked, but until recently no studies or clinical trials had been initiated to determine if the COVID vaccine could affect sperm count in men.

The Centers for Disease Control and Prevention maintains that there is no evidence that COVID-19 vaccines can cause male or female infertility. The only fertility studies published on the CDC website exclusively examine pregnancy in women and neonatal surveillance, however.

To better understand the issue, researchers at the University of Miami conducted a study between December 17, 2020 and January 12, 2021 to assess men’s fertility after vaccination. The findings, published in the Journal of the American Medical Association, found no adverse effects on participants’ sperm count.

Researchers recruited 45 healthy male volunteers, aged 18 to 50, who were scheduled to be vaccinated. Of the 45, 21 received the Pfizer vaccine and 24 received the Moderna vaccine. Participants were prescreened to make sure they had no underlying fertility issues, and those with a positive COVID test within 90 days of the study or any COVID-19 symptoms were excluded. 

After two to seven days of self-imposed abstinence, semen samples were taken from the men. Samples were taken before the first vaccine dose and 70 days after the second dose. A complete sperm regeneration cycle, known as “spermatogenesis,” takes approximately 64 days.

The samples were then analyzed and compared for semen volume, sperm concentration, sperm motility, and total motile sperm count. No significant decrease was found in any of the tested parameters, and eight participants who had low sperm counts before getting vaccinated returned to normal levels by the time of their second sample.

Dr. Jesse Ory, a co-author of the study and urology fellow in infertility and andrology at the University of Miami Miller School of Medicine, told USA Today it was “an unknown area that was making guys nervous to get the vaccine.”

One of the primary reasons behind vaccine hesitancy is the potential negative effect on fertility, according to the study, as early clinical trials did not evaluate reproductive toxicity.

“That’s not saying the vaccine increased sperm,” Ory added. “But even in guys who have low sperm count who may be worried about their fertility, they don’t need to worry that this vaccine will impact their fertility any further.”

The findings of the study were more or less in line with what scientists expected. But while we can now rule out the possibility of a COVID vaccine causing infertility, a severe COVID-19 infection could negatively impact sperm count, according to Dr. Sigal Klipstein, chair of the ethics committee at the American Society of Reproductive Medicine.

“Getting COVID can be potentially detrimental to their fertility, and getting the vaccine is safe and could even protect fertility by protecting you against the severe effects of COVID disease,” Klipstein said.

Read more on the coronavirus vaccines:

Sources: USA Today, JAMA

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