SARS-CoV-2 vaccination and semen quality: a study based on sperm donor candidate data in southwest China.

Background: The coronavirus disease 2019 (COVID-19) pandemic has been a global health crisis and continues to pose risk to population health at the present. Vaccination against this disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has become a public health priority worldwide. Yet, limited information is available on the potential impact of such vaccines on human fertility.

Methods: To examine the relationship between COVID-19 vaccination and male fertility, we conducted an observational study on sperm donor candidates in China who received Chinese COVID-19 vaccines between January 1, 2020 to December 31, 2021.

Results: A total of 2,955 semen samples from 564 individuals were assessed along with vaccination information. Statistical analyses were conducted on both the entire study population and the subgroup of individuals who provided repeated semen samples before and after vaccination. While motility related parameters [progressive rate, curvilinear velocity (VCL), average path velocity (VAP), straight-line velocity (VSL), wobble (WOB), straightness (STR), linearity (LIN), amplitude of lateral head displacement (ALH), beat-cross frequency (BCF)] exhibited statistically significant difference before and after vaccination based on Welch two-sample test, mixed effects regression results based on repeated measures from the same individuals indicated that vaccination was not statistically associated with sperm quality parameters except for VCL, VAP, and VSL. Individual variability was the key determinant of sperm quality variance, with contribution ranging from 19% to 82%.

Conclusions: Findings from our study could help to enhance current understanding of male reproductive health in the context of the global pandemic.