Sperm Parameters Before and After COVID-19 mRNA Vaccination

This small single-centre study of 45 healthy volunteers aged 18-50 years found receipt of the mRNA Covid-19 vaccine was not associated with any significant decreases in any sperm parameter.

SPS commentary:

One of the reasons for vaccine hesitancy is misinformation about potential negative effects on fertility. As reproductive toxicity was not evaluated in the vaccine clinical trials and SARS-CoV-2 has been associated with decreases in sperm parameters, the authors of this study assessed sperm parameters before and after Covid-19 mRNA vaccine administration. In relation to their findings, they say the vaccines contain mRNA and not the live virus, so it is unlikely that the vaccine would affect sperm parameters.

This study is limited by its small size, inclusion of only young and healthy men, and the short follow-up. In addition, semen analysis is an imperfect predictor of fertility potential. Despite this, the study’s time frame encompasses the full life cycle of sperm.

Journal of the American Medical Association