What influence has COVID-19 vaccination had on sperm characteristics?

In a recent study published in the Asian Journal of Andrologyresearchers assessed the influence of vaccination against coronavirus disease 2019 (COVID-19) on sperm characteristics.

Background

Regarding the consequences of COVID-19 on male fertility are among the non-respiratory symptoms, poor spermatogenesis probably reflecting the course of the infection. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have been associated with decreased sperm quality, their reproductive toxicity has not been evaluated in the clinical setting. Previous research has linked sperm quality and fertility to mortality and population health; therefore, immunization can have a considerable impact on sperm parameters.

About the study

In the current study, researchers examined the differences between sperm parameters before and after the administration of various SARS-CoV-2 vaccines.

The Embase and PubMed databases were merged with the search phrases: vaccination, COVID-19 and sperm parameters to detect the search for candidates. Using the Principles of Population, Intervention, Comparison, and Outcomes (PICOS), the team selected articles that met the criteria for inclusion in the meta-analysis: (1) P (population): participants who n ‘had no prerequisite likely to reduce sperm count quality; (2) I (intervention): SARS-CoV-2 vaccinations were the only intervention; (3) C (comparison): comparison made between the vaccinated and unvaccinated population and the included participants themselves; (4) O (results): results such as relevant assessments such as semen volume, semen concentration and total sperm motility. Before and after COVID-19 vaccinations, the impact of messenger ribonucleic acid (mRNA) COVID-19 vaccines on sperm volume, sperm concentration, total sperm count, and total sperm motility was assessed.

Results

Seven studies selected from the database were assessed for their quality and included in the quantitative analysis. Comparing sperm variables before and after COVID-19 vaccination required data from multiple studies, including six studies involving 920 patients for sperm concentration and sperm volume, six studies involving 1674 patients assessed for total sperm motility, two studies involving 1110 patients assessed for total sperm count and two studies involving 332 patients for morphological assessment. The team noted significant variations in overall sperm motility before and after vaccination with COVID-19, while significant heterogeneity was noted. The funnel plot demonstrated that this comparison contained no appreciable publication bias.

There were no variations in volume before and after vaccination against COVID-19. Moreover, no discernible heterogeneity was found. In this comparison, no substantial publication bias was noted. This overall result is reliable, given that fluid significantly affects semen volume. Thus, this feature may primarily represent the impact of vaccination on fluid-secreting glands. There was no evidence of heterogeneity among the primary outcomes of the included studies. Overall, there was no variation in sperm concentration before and after administration of the COVID-19 vaccination.

The team observed no significant reduction in total sperm count after the administration of the COVID-19 vaccination. Three studies looked at a comparison of sperm morphology, with one reporting an aberrant rate and two reporting a normal rate. Without considerable heterogeneity, there was no discernible morphological change after immunization.

Overall, the study results showed that the most recent evidence reported no adverse effects of the administration of inactivated or mRNA COVID-19 vaccines on sperm parameters. The researchers believe there is an urgent need for additional prospectively structured research to confirm this finding.