Introduction: Vaccine hesitancy is a major public health obstacle to fighting the ongoing COVID-19 epidemic. Due to studies that show COVID-19 infection can affect sperm parameters and lead to orchitis, the public are concerned about how the COVID vaccines may impact male reproduction. In this study, we investigated the association between COVID-19 vaccination and risk of developing orchitis and/or epididymitis outcomes in a cohort of men using a large, US-based, electronic health record database (TriNetX).
Methods: We queried the database for male patients ages 12 years and older who received a single-dose COVID-19 vaccine or at least 1 dose of a 2-dose regimen using specific ICD-10 medication and procedure codes and compared them to a cohort of men who had no record of any COVID-19 vaccination in their health record. The outcome for analysis was diagnosis of orchitis and/or epididymitis (ICD-10-CM: N45-N45.4, N51) between 1-9 months after the index event of COVID-19 vaccination. The two cohorts were balanced for the following potentially confounding variables through propensity score matching: age at index event, race, urinary tract infection, and unspecified sexually transmitted disease. We determined the association between COVID-19 vaccination and orchitis and/or epididymitis using logistic regression analysis with statistical significance assessed at p < 0.05.
Results: We identified 663,774 men in the database who had received at least one dose of a COVID-19 vaccine, and 9,985,154 who did not. Prior to propensity score matching, 0.051% of men in the vaccinated cohort and 0.083% in the unvaccinated cohort received a diagnosis of orchitis and/or epididymitis in the time window (OR = 0.619; 95% CI: 0.556 - 0.690; p < 0.0001). After balancing for potentially confounding variables, the COVID-19 vaccine remained protective against development of orchitis and/or epididymitis (OR = 0.568; 95% CI: 0.497 - 0.649; p < 0.0001).
Conclusions: In this retrospective cohort study, we demonstrated that receiving a COVID-19 vaccine is associated with a decreased risk of developing orchitis and/or epididymitis. These findings have important implications in the counseling of patients that are hesitant to receive the COVID-19 vaccine and refute misinformed claims on social media regarding the effect of the vaccines on male fertility.
Source of Funding: This work was supported by National Institutes of Health Grant R01 DK130991 and the Clinician Scientist Development Grant from the American Cancer Society to Ranjith Ramasamy.