SoylentNews

DannyB [soylentnews.org] writes:

Sperm Parameters Before and After COVID-19 mRNA Vaccination [jamanetwork.com]

Two mRNA vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna), received Emergency Use Authorization from the US Food and Drug Administration. Despite high efficacy and few adverse events found in clinical trials, only 56% of individuals in the US reported wanting to receive the vaccine. One of the reasons for vaccine hesitancy is the potential negative effect on fertility.

[....] This single-center prospective study at the University of Miami recruited healthy volunteers aged 18 to 50 years scheduled for mRNA COVID-19 vaccine through flyers posted throughout the university hospital and internal listserve emails. [....] Participants provided a semen sample after 2 to 7 days of abstinence, prior to receiving the first vaccine dose and approximately 70 days after the second.

[....] After calculating data distribution on normality test, medians and interquartile ranges (IQRs) were reported for all variables. Wilcoxon rank sum test was used to compare pre- and postvaccination semen parameters. Change in TMSC (total motile sperm count) is presented graphically. Statistical analysis was performed with SPSS version 24 (IBM). A 2-tailed P value less than .05 was considered statistically significant.

Results

Baseline sperm concentration and TMSC were 26 million/mL (IQR, 19.5-34) and 36 million (IQR, 18-51), respectively. After the second vaccine dose, the median sperm concentration significantly increased to 30 million/mL (IQR, 21.5-40.5; P = .02) and the median TMSC to 44 million (IQR, 27.5-98; P = .001). Semen volume and sperm motility also significantly increased. [....] 7 men had increased sperm concentration to normozoospermic range at follow-up [...] and 1 man remained oligospermic. No man became azoospermic after the vaccine.

Discussion

[....] there were no significant decreases in any sperm parameter among this small cohort of healthy men. Because the vaccines contain mRNA and not the live virus, it is unlikely that the vaccine would affect sperm parameters. While these results showed statistically significant increases in all sperm parameters, the magnitude of change is within normal individual variation and may be influenced by regression to the mean. Additionally, the increase may be due to the increased abstinence time before the second sample. Men with oligospermia did not experience further decline.

The limitations of the study include the small number of men enrolled; limited generalizability beyond young, healthy men; short follow-up; and lack of a control group. [....]

The article has various footnotes and a table.

Original Submission