There are 3 vaccines available to prevent COVID-19 disease in the United States, including 2 mRNA vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna), and 1 viral vector vaccine from Johnson & Johnson. As of March 2022, despite high efficacy and few adverse effects of vaccines, about 25% of adults were not fully vaccinated in the U.S.¹ Diaz et al showed that a significant reason for vaccine hesitancy in the U.S. is the fear of the negative impact and irreversible damage of the COVID-19 vaccination on fertility.² The concern about the adverse effects of the COVID-19 vaccine on male fertility may arise from several studies that showed the COVID-19 virus could temporarily impair sperm parameters and lead to orchitis, epididymitis and erectile dysfunction.³

We conducted a prospective study evaluating sperm parameters in 45 men prior to vaccination and at a median of 75 days after the second dose of vaccine administration. Participants did not have any underlying fertility issues, and their age was between 18 and 50 years. This study showed no decrease in any semen parameters, including semen volume, sperm concentration, total motility and total motile sperm count before and after 2 doses of COVID-19 vaccine (Pfizer and Moderna) among the participants.⁴ In a similar study conducted in an in vitro fertilization center in Israel, the authors assessed the effects of the BNT162b2 COVID-19 vaccine on sperm parameters in 72 men with a normal or abnormal semen analysis.⁵ In that study, participants served as self-control, and their sperm parameters before and after the second vaccination dose were compared. The study showed no significant changes in the sperm parameters before and after BNT162b2 vaccine administration in both normal and abnormal semen analysis.

We investigated the association between the administration of single-dose or at least 1 dose of COVID-19 vaccine and the risk of subsequent orchitis and/or epididymitis.⁶ In this large electronic health record database, we found that men who received at least 1 dose of the COVID-19 vaccine had diminished odds of developing orchitis and/or epididymitis.

Although there is enough evidence to show that infection with SARS-CoV-2 cannot be sexually transmitted, it is considered a transient threat for the reproductive system in men and can impair semen quality. COVID-19 infection can lead to a decrease in sperm concentration and total motility of sperm and an increase in abnormal sperm morphology and DNA fragmentation. Some reports suggest that these findings could be due to impairment in the hypothalamic-pituitary-gonadal axis, dysfunction of Leydig cells in the testis, fever, inflammation, and increased immune response and cytokine storm in the testis. Contrary to these studies, research about the effects of COVID-19 vaccination on men’s fertility has not demonstrated any adverse effect on the reproductive system.⁷ The authorized vaccines contain mRNA and not the live virus; therefore, they are not expected to affect semen quality and sperm parameters.

In conclusion, the COVID-19 vaccine should be considered safe and does not affect sperm parameters and male fertility potential, whereas COVID-19 infection appears to affect male fertility potential. Long-term studies are necessary to fully understand the impact of COVID-19 on male reproduction.