One of the many urban legends related to COVID-19 vaccines is that they cause infertility. Researchers at the University of Miami set out to disprove that claim with a recent single-center prospective study. Unsurprisingly, the study that indicated the mRNA vaccines have no negative impact on male fertility. In fact, the researchers found that after the second vaccine dose, participants exhibited a significant increase in median sperm concentration and sperm motility.
In the study published in JAMA, the researchers stopped short of claiming that mRNA COVID-19 vaccines could boost fertility in men. “While these results showed statistically significant increases in all sperm parameters, the magnitude of change is within normal individual variation,” the study authors concluded.
The study only evaluated the BNT162b2 and mRNA-1273 vaccines from Pfizer-BioNTech and Moderna, respectively.
The study tracked participants approximately 70 days after administering the second vaccine dose, which provided an opportunity to follow the entire lifecycle of sperm.
The researchers acknowledged that the small size of the study, which involved 45 participants, was a limitation.
Researchers at the University of Miami have also concluded that COVID-19 infection could interfere with fertility.
Prior animal studies involving COVID-19 vaccines do not suggest that they pose a risk of reproductive toxicity.