Do COVID vaccines affect male fertility?

Vaccines do have side effects, but there are some social-media users peddling myths that COVID-19 vaccines cause male infertility and sexual dysfunction.

This is not the case – there is no established link between COVID vaccines and male fertility, though falling ill with COVID-19 may pose a risk of sexual dysfunction.

Do vaccines cause infertility in males?

Currently there is no evidence that sperm count, semen volume and sperm motility are negatively affected by a vaccine. In fact, there is no evidence that any vaccine at all causes infertility in either males or females.

One preprint study, submitted in May 2021, found no difference in sperm characteristics of 43 men before and after vaccination with Pfizer. The volunteers came from a pool of men receiving IVF services, and 32% of the participants already had ineffective sperm.

Another study published in JAMA quantified sperm volume of 45 men before and after two doses of an mRNA vaccine (either Pfizer or Moderna) and saw no decrease in sperm count 70 days – the life cycle of a sperm – following the second dose. In fact, it found that semen volume, sperm count and sperm motility all significantly increased.

Eight of the men had low sperm count prior to vaccination, but this increased to normal levels after.

“Because the vaccines contain mRNA and not the live virus, it is unlikely that the vaccine would affect sperm parameters,” the authors point out in the paper.

In 2017, about seven in 1000 men of reproductive age were affected by male infertility. With 2.8 billion people fully vaccinated globally, we would expect to see a significant and large increase in reported male infertility in 2021 – except we haven’t seen this reported.

The International Federation of Fertility Societies, the European Society of Human Reproduction and Embryology, the American College of Obstetricians and Gynecologists, the British Fertility Society and the Association of Reproductive and Clinical Scientists have all released statements that there is no evidence that COVID-19 vaccines cause infertility.

There were no Therapeutic Goods Administration reports of infertility or fertility issues following the administration of 28.7 million vaccine doses in Australia, but there were six mentions of penile discomfort. There was no established link, however, between the vaccine and the discomfort.

Regardless, public concern does remind us that research about COVID-19, vaccines and male fertility is crucial.

Why do people claim there is a link between vaccines and infertility? 

The nature of vaccine hesitancy is complex. Sometimes, rumours can circulate because a question was asked that became misconstrued over time as a statement.

Other times, a fact may be taken out of context.

The Society for Male Reproduction and Urology (SMRU) and the Society for the Study of Male Reproduction (SSMR) issued a joint statement with this example: “It should be noted that about 16% of men in the Pfizer/BioNtech COVID-19 vaccine clinical trial experienced fever after the second dose. Fevers can cause temporary declines in sperm production. Thus, if a man experiences fever as the result of the COVID-19 vaccine, he may experience a temporary decline in sperm production, but that would be similar to or less than if the individual experienced fever from developing COVID-19 or for other reasons.”

Since the life cycle of a sperm is only 70 days, future sperm production is unlikely to be affected by a fever.

In another instance, a circulating video involving Dr Roger Hodkinson stated that ACE2 receptor “is present in the testes” and “it’s actually on the cells that produce spermatozoa”. The video was accompanied by rhetoric claiming that this showed vaccines were unsafe.

However, many facts were omitted.

First of all, this information was based on a paper published in Biology of Reproduction. In the study, researchers found that the ACE2 receptor, which is found on the cell membrane of some organs, was high in the testes and interacted with SARS-CoV-2. Because of this, the researchers suggested there should be further research into the association between male reproductive health and male COVID patients.

The key here is that this study was not about vaccines – it was about the coronavirus itself.

The researchers told FactCheck that the paper “is a hypothetical article about the potential effect of SARS-CoV-2 infection on male reproductive health, not about the impact of COVID-19 vaccine on male reproductive health”.

Ironically, the paper didn’t prove that SARS-CoV-2 influenced male fertility, either.

But it did prompt further research.

Does COVID cause infertility?

There isn’t an established link between COVID-19 and sperm count, but there is evidence that the virus is present in the testes and penis.

An autopsy of six men who died of COVID showed that three of them had a lower sperm count than expected, although this is a small sample and may not represent all survivors.

Likewise, the biopsy of another patient who recovered from COVID showed that the virus was still present in the testes three months later.

The same team also found that coronavirus affected the penis, with the virus still present in the penile tissue of two men seven and nine months after their diagnosis. Both men had developed erectile dysfunction, potentially because the infection reduced blood flow.

This trend is consistent with studies on the 2006 SARS outbreak, which is a close cousin of COVID.

A meta-analysis published in March suggested that there hadn’t been enough time to assess the long-term effects of COVID-19 on sperm count and quality, but there is definite evidence of an effect on testes and penile tissue, including inflammation and testicular discomfort in up to 19% of male patients.  

While the effect of COVID-19 on sperm count is inconclusive at this stage, it is still highly unlikely that COVID vaccines can cause male infertility.