Does mRNA SARS-CoV-2 vaccine detrimentally affect male fertility, as reflected by semen analysis?

Abstract Research question Does Pfizer's Covid-19 vaccination detrimentally affect semen analysis parameters? Design We conducted a prospective cohort study in a single large tertiary center in Israel between February and March of 2021. Semen samples of 75 fertile men were analyzed 1-2 months following the second dose of Pfizer's covid-19 vaccine. The semen parameters were compared to the WHO reference ranges. The primary outcome was the percentage of abnormal semen parameters in those vaccinated, i.e. the rates of oligozoospermia, reduced percentage of motile sperm and abnormal sperm morphology. Results The interval from the time of the second vaccine to the date of participation was on average 37 days, with most subjects describing either mild or no side effects after the first or second dose. The mean sperm concentration was 63.2±33.6 10^6 ml with only a single subject (1.3%) with sperm count of 12.5 10^6 ml, considered by the WHO as oligozoospermic. The mean sperm motility percentage was 64.5%±16.7 with only a single subject (1.3%) displaying reduced motility. No significant morphological abnormalities were observed. This constituted a significantly lower percentage of abnormal semen parameters compared with the 5% rates reported in fertile men by the WHO. Conclusions The semen parameters following Covid-19 vaccination were predominantly within normal reference ranges as set by the WHO and do not reflect any causative detrimental effect from COVID-19 vaccination. Our results strengthen the notion that the Pfizer's SARS-CoV-2 vaccine is safe and should be recommended to fertility seeking men. ClinicalTrials.gov number, NCT04778033.