Effects of inactivated SARS-CoV-2 vaccination on male fertility: A retrospective cohort study

Numerous studies have revealed severe damage to male fertility from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, raising concerns about the potential adverse impact on reproductive function of the coronavirus disease 2019 (COVID-19) vaccine developed based on the virus. Interestingly, there are several researchers who have studied the impact of the COVID-19 mRNA vaccine since then but have come up with conflicting results. As a near-ideal candidate for mass immunization programs, inactivated SARS-CoV-2 vaccine has been widely used in many countries, particularly in less wealthy nations. However, little is known about its effect on male fertility. Here, we conducted a retrospective cohort study at a single large center for reproductive medicine in China between December 2021 and August 2022. Five hundred and nineteen fertile men with no history of laboratory-confirmed COVID-19 were included and categorized into four groups based on their vaccination status: unvaccinated group (n = 168), one-dose vaccinated group (n = 8), fully vaccinated group (n = 183), and booster group (n = 160). All of them underwent a semen analysis and most had serum sex hormone levels tested. There were no significant differences in all semen parameters and sex hormone levels between the unvaccinated group and either vaccinated group. To account for possible vaccination-to-test interval-specific changes, sub-analyses were performed for two interval groups: ≤90 and >90 days. As expected, most of the semen parameters and sex hormone levels remained unchanged between the control and vaccinated groups. However, participants in vaccinated group (≤90 days) have decreased total sperm motility and increased follicle-stimulating hormone level compared with the ones in unvaccinated group. Moreover, some trends similar to those found during COVID-19 infection and recovery were observed in our study. Fortunately, all values are within the normal range. In addition, vaccinated participants reported few adverse reactions. No special medical intervention was required, and no serious adverse reactions happened. Our study suggests that inactivated SARS-CoV-2 vaccination does not impair male fertility, possibly due to the low frequency of adverse effects. This information reassures young male population who got this vaccine worldwide, and helps guide future vaccination efforts.