In conclusion, in this longitudinal multicenter study, we found a selective temporary decline of sperm concentration and total motile count 3 months post-vaccination followed by recovery among SD. While on first look, these results may seem concerning, from a clinical perspective they confirm previous reports regarding vaccines' overall safety and reliability despite minor short-term side effects. Since misinformation about health-related subjects represents a public health threat, our findings should support vaccinations programs. Further studies concentrating on different vaccines and populations (ex. subfertile patients) are urgently required.