Israeli MD analyzes billions of sperm, finds COVID vaccines don’t harm fertility

Hadassah doctor hopes to allay false fears vaccine harms men’s ability to conceive, after surveying samples from before and after vaccination and finding there’s no change

Nathan Jeffay is The Times of Israel's health and science correspondent

Illustration of humam sperm (vchal  via iStock by Getty Images)
Illustration of humam sperm (vchal via iStock by Getty Images)

Pfizer’s coronavirus vaccine isn’t affecting sperm, a first-of-its-kind Israeli study has concluded, offering reassurance to couples around the world who are trying to conceive.

Dr. Myriam Safrai of Jerusalem’s Hadassah Medical Center analyzed sperm given pre- and post-vaccination by 72 men, and found that there was no notable change in count or quality. Her results held true whether the men had normal sperm pre-vaccination, or faced challenges of a low sperm count or low motility.

“There are fears among some people that vaccines will harm sperm, but this study calms the fear,” Safrai told The Times of Israel. “And given that there is research showing that COVID-19 does harm sperm in 25 percent to 30% of cases, it’s clear from this that men who want to conceive should be vaccinating.”

Safrai’s research suggests that inaccurate rumors of vaccines harming sperm are discouraging some men. She is a fertility doctor at Hadassah’s IVF department and found that while among the Israeli population 71% to 85% of men of the age range she serves are vaccinated, among her IVF couples the figure is 58%.

“We’re seeing that this population accepts the vaccine less, which we suspect is because of a fear it will harm sperm,” Safrai said.

The study, which is available online but not yet peer-reviewed, analyzed sperm samples that are available because the men have been involved in IVF treatment before and after vaccination.

Illustrative image: A lab in an IVF clinic (AP Photo/Richard Drew)

Some of the men have normal sperm and are undergoing IVF just because their partner faces fertility issues. Others have problems with their sperm.

A smaller study of 45 men, published in June, found that there were no significant sperm changes, and observed: “Because the vaccines contain mRNA and not the live virus, it is unlikely that the vaccine would affect sperm parameters.” But there were only eight men with low sperm counts among the subjects of that study.

Safrai said hers is the first study to feature a wide range of starting sperm counts and qualities, and that is was an important undertaking. That is because the research showing that men with normal sperm aren’t affected fails to reassure some men who have problems with their sperm, and fear a vaccine will intensify them.

“When we looked at the group as a whole, there is no difference in sperm before and after vaccination, and the same was true when we looked at either just the normal sperm or just the impaired sperm,” she commented.

“What we understand is that the virus can enter the testes and harm sperm, but there is no negative impact from the vaccine. Just as women trying to conceive are encouraged to take the vaccine for a healthy pregnancy, men who are trying to conceive should take the vaccine to protect their sperm.”

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