BACKGROUND AND PURPOSE:

• Concerns about impact on fertility are frequently cited among those hesitant to receive the COVID-19 vaccine
• Diaz et al. (F&S Reports, 2022) updated their previous study to assess the long-term impact of COVID-19 vaccination on male fertility potential 

METHODS:

• Single center prospective follow-up study
• Participants
  • Healthy male volunteers
  • Between the ages of 18 and 50 years
  • Received 2 doses of an mRNA COVID-19 vaccine and participated in the previous survey at 3 months post-vaccination
• Exposures
  • Time since vaccination (baseline, 3 months, 9+ months)
• Study design
  • Semen was collected 9 months post-vaccination and assessed for volume, sperm concentration, motility, and total motile sperm count (TMSC)
• Primary outcome
  • Median change in TMSC at the different exposure time points following vaccination

RESULTS:

• 12 men
  • Median age: 26 (IQR, 25 to 30) years
  • Median time since second vaccination dose: 10 months
  • Received a booster: 50%
  • Had a history of COVID-19: 33%
• There was no difference in TMSC at baseline, 3 months, and 9+ months (P=0.519)
  • Baseline: median 31 (IQR, 4 to 51.3) million
  • 3 months: median 33 (IQR, 13.5 to 85) million
  • 9+ months: median 37.5 (IQR, 8.5 to 117.8) million
• There were no significant differences in any of the sperm parameters at any time point

CONCLUSION:

• There were no long-term (9+ months) significant differences in sperm parameters following mRNA COVID-19 vaccination
• The authors state

A plausible explanation for this maintenance of semen parameters may be due to the mechanism of the mRNA vaccine, lack of live virus, and its inability to alter an individual’s DNA

In addition, the apparent absence of mRNA localization to the gonads is most likely in part due to the blood testis barrier

Learn More – Primary Sources:

Long-Term Evaluation of Sperm Parameters Following COVID-19 mRNA Vaccination