ABSTRACT
This systematic review and meta-analysis assessed the effects of SARS-Cov-2 and mRNA vaccines on male reproduction. We conducted a comprehensive search using terms such as "COVID-19," "vaccine," and "sperm parameters" on various electronic databases, including MEDLINE (PubMed), BVS (LILACS and others), Embase (Elsevier), and Cochrane Library. We included observational studies, including cohort, case-control, and cross-sectional studies. Of the 2054 records initially identified, we carefully examined 47 full-text articles and excluded 26 articles for specific reasons, ultimately including 21 studies for our analysis. Among these, 16 studies focused on assessing seminal parameters in patients with COVID-19, while five studies investigated the effects of COVID vaccines on seminal parameters. A meta-analysis of seminal parameters in men before and after the COVID-19 pandemic revealed significant differences in seminal concentration, progressive motility, total motility, and normal morphology. These findings indicate a positive impact of the analyzed parameters before the onset of COVID-19. However, the quality of the evidence was considered low. In contrast, a meta-analysis of five studies evaluating seminal parameters before and after the SARS-Cov-2 vaccine did not show any significant differences in total motility. This analysis, involving 256 men from four studies, provided low-quality evidence, suggesting that mRNA vaccines do not affect male reproduction. Overall, our findings suggest that seminal parameters exhibit considerable variability depending on specific outcomes and the study design. However, based on available evidence, it appears that mRNA vaccines do not have detrimental effects on male reproductive function.
