Fact Check-No evidence mRNA COVID-19 vaccines affect sperm

A video message by an osteopath known for her anti-vaccination campaigns and conspiracy theories says that mRNA-based COVID-19 shots may affect sperm and cause infertility. As of this fact-check’s publication, there is no evidence to back up these statements.

Examples of Dr Sherri Tenpenny’s video can be seen here and here .

Tenpenny wrongly says men have been advised not to have unprotected sex for at least six weeks after receiving Pfizer’s mRNA-based vaccine. She said that in her opinion, that is because the so-called “spike protein” from the virus could bind to the surface of the sperm and could change the sperm’s DNA, slow it or kill it, causing infertility or birth defects.

She also wrongly says women have been advised not to get pregnant for at least two months after getting a Pfizer shot. “Why?,” Tenpenny asks in the video. “Because the spike protein can bind to the ovary and we have no idea what the spike protein and the antibody to the spike protein could possibly do to the reproductive tract.

Tenpenny goes on to suggest this is all linked to a conspiracy by “the globalists and the de-population eugenicists, the stated Satanists who are out to destroy the world”.


Tenpenny has been called out for her anti-vaccination activism and spread of vaccine-related misinformation online, as reported by the BBC here , McGill University in Canada here and ABC Australia here .

Fact-checkers PolitiFact and Snopes have also found COVID-19 related statements by Tenpenny to be repeatedly false, visible here and here .

Tenpenny did not immediately respond to Reuters’ request for comment.


Further studies are needed to know how and if COVID-19 infection may damage men’s fertility.

Reuters reported in November 2020 that some small autopsy studies suggested infection with COVID-19 might affect male fertility (here).

Researchers from the University of Miami in Florida compared testis tissues from six men who died of COVID-19 and three who died of other causes. Three of the COVID-19 patients had testis damage that would impair their ability to produce sperm. A Chinese research team made similar observations earlier this year and also found that some COVID-19 patients’ immune systems “attacked” the testes, causing severe inflammation, or orchitis.


There is currently no credible scientific evidence supporting the central claim made in the video that mRNA COVID-19 vaccines damage men’s sperm.

A study out of Israel published on May 3, 2021 (here), sought to investigate whether mRNA vaccines for COVID-19 affected sperm. They found “ the vaccine does not impair sperm parameters,” and actually recommended “couples desiring to conceive should vaccinate, as vaccination does not affect sperm whereas SARS-CoV-2 infection does impair sperm.”


Tenpenny’s statements about unprotected sex and pregnancy appear to come from a misinterpreted 146-page Pfizer document here outlining its protocol for clinical trials.

This misunderstanding has been explained here and here . The document does not set out guidance for men and women getting COVID-19 vaccines. It sets out guidance for Pfizer’s clinical trials for the vaccine.

The National Institute of Health recommends here that contraceptive methods be used by participants during clinical trials regardless of whether the substance being tested poses risk to a fetus. This is standard procedure: drug trials of any kind usually ask women avoid getting pregnant during its extent, and trials on pregnant women are usually done separately with specific extra safety requirements after a drug was deemed safe in healthy adults (here, here ).


Current guidance by the college and the Centers for Disease Control and Prevention (CDC) here and here. is that there is no evidence that the vaccines cause fertility problems and that women do not need to delay getting pregnant after receiving the vaccine.

The American Society for Reproductive Medicine (ASRM) recommends the COVID-19 vaccine to those who are pregnant or plan to become pregnant, to minimize COVID-19 infection risks to themselves and their pregnancy (here).

Reuters has previously debunked the claim that mRNA-based vaccines alter DNA here , here , here and here .

It has also has previously debunked claims that COVID-19 vaccines are linked to infertility or miscarriages here , here and here .


No evidence. As of this article’s publication, there is no evidence the mRNA COVID-19 vaccines affect men’s sperm.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work  here  .