Vaccination does not make any difference to sperm count or quality, but infection does.
"Given that SARS- CoV-2 infection may impair male fertility, couples desiring to conceive should vaccinate, as vaccination does not affect sperm, whereas SARS-CoV-2 infection does impair sperm parameter."
"In this study of sperm parameters before and after 2 doses of a COVID-19 mRNA vaccine, there were no significant decreases in any sperm parameter among this small cohort of healthy men."
"we observed no influence of mRNA SARS-CoV-2 vaccine on patients’ performance during their immediate subsequent IVF cycle"
"... it is evident that (i) there is testicular injury and inflammatory infiltration (ii) viral orchitis may occur, as patients experienced scrotal discomfort (iii) there is altered semen parameters and (iv) the number of spermatozoa with DNA fragmentation is increased. These results collectively suggest that infection with SARS−COV-2 may lead to potential fertility issues."