Do Covid-19 Vaccines Affect Fertility?


Science-Based Medicine

Harriet Hall on May 31, 2022

Fears of future infertility are keeping some parents from vaccinating their children for COVID-19. These fears are not supported by any evidence.

A friend told me he had encountered a man who was fully vaccinated. This man says his whole family is vaccinated except his young 7-year-old daughter. He says he’s worried about the effect on her fertility or future reproductive abilities. My friend asked me to point to the best evidence that this shouldn’t be a concern.

I had not encountered this concern before, so I did some Googling. I couldn’t find any “best evidence” or indeed, any evidence at all. It appears that this is a social media myth based on an assumption that the vaccine could cause the body to attack syncytin-1, a protein in the placenta that shares a small piece of genetic code with the spike protein of the coronavirus. One expert dismisses this concern, saying “the overall construction of the protein is so completely different, your immune system is way too smart to be confused by that.”

Another expert, in China, is concerned because the angiotensin 2 converting enzyme (ACE2) is present in the ovaries and testes. He thinks SARS-CoV-2 infection might disrupt ovarian function and hence oocyte quality. And it might impair spermatogenesis.

Another paper from China by the same authors says “Whereas COVID-19 has not yet been reported to damage female fertility, its potential detrimental effects cannot be ignored”.

The British Medical Journal reports that a protocol for systematic review and meta-analysis has been developed to study these concerns, and research is ongoing. This was also based on the concerns of Chinese scientists. This worries me, since a 2016 study found that 80% of China’s clinical trial data are fraudulent.

I must admit that the man’s fears are not entirely unwarranted. Science-based concerns have been raised. This is an area that calls for more study. At present, there simply is no evidence one way or the other.

On the other hand, there IS clear evidence that the disease can kill children, and dead children are unable to reproduce. So I would emphasize the solid evidence for that risk in contrast to the purely speculative and hypothetical risks of possible reproductive consequences that have not yet been evaluated and for which there is no evidence. Of course, he wants to be cautious and protect his child, but in the worst-case scenario, wouldn’t it be better to have an infertile daughter than a dead one? And of course, if she remains unvaccinated and is infected by SARS-CoV-2, she would be a source of risk to other people, especially the very young and the very old.

That man’s fears are based on speculation and hypotheses, not evidence, but they may well prove stronger than rational arguments and evidence. Anyway, the effort to change his mind is worth a try, if only in the interests of public health. Don’t we have a duty to protect vulnerable individuals?

Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren’t Supposed to Fly.