The COVID-19 pandemic not only changed our daily lives but also raised questions about reproductive health. In particular, the debate over “unvaccinated vs. vaccinated sperm” is clouded by myths. What does the research actually show? In this article, we’ll clear up the facts, dispel misconceptions, and explain which factors truly influence sperm quality.
Why Sperm Quality Matters: The Basics
Sperm are specialized cells that deliver the male genetic material to the egg. Each sperm cell plays a key role, providing 50% of the genetic material for new life.
Sperm quality is evaluated based on four main parameters:
- Concentration: Number of sperm per milliliter of ejaculate
- Motility: Movement and forward progression
- Morphology: Percentage of normally shaped sperm
- DNA Integrity: Intactness of genetic material
These values are sensitive to illness, lifestyle, and environmental factors. But does the COVID-19 vaccine also affect sperm?
Scientific Studies on COVID-19 Vaccination and Sperm Quality
Researchers worldwide have been examining whether mRNA and vector vaccines alter sperm parameters. The clear message: there is no evidence of lasting impairment.
A JAMA study (Gonzalez et al., 2021) compared sperm parameters in 45 healthy men before and after mRNA vaccination and found no significant differences in concentration, motility, or morphology (Gonzalez DC et al. 2021).
A systematic review of 24 studies (Chen et al., 2023) showed that neither mRNA nor vector vaccines have clinically relevant effects on sperm count, motility, or DNA integrity. Read more
COVID-19 Infection vs. Vaccination: Risk vs. Protection
A cohort study demonstrated that SARS-CoV-2 infection can temporarily reduce all sperm parameters and cause DNA fragmentation, while vaccination shows none of these effects (Yuan et al., 2025) Read the study.
The WHO and CDC therefore recommend vaccination not only to prevent COVID-19 but also to protect your fertility. CDC: COVID-19 Vaccination for Those Planning Pregnancy
Long-Term Studies and Emerging COVID-19 Vaccines
Alongside the evaluated mRNA and vector vaccines, several long-term studies—such as those at universities in Canada and Japan—are tracking men over 12 months, collecting regular samples and health data to rule out very rare effects.
Additionally, protein-based vaccines (e.g., Novavax) and other platforms are under review. Early immune response data show high efficacy with mild side effects. Since these vaccines also do not enter gonadal tissue, experts do not expect them to impair sperm quality. Results are expected to be published in the coming months.
Lifestyle and Environment: Keys to Healthy Sperm Quality
To boost fertility, pay attention to:
- Nutrition: Plenty of fruits, vegetables, and omega-3 fatty acids; avoid alcohol and nicotine
- Exercise & Weight: Regular physical activity and a healthy BMI
- Stress Management: Relaxation techniques like yoga or meditation
- Environment: Minimize exposure to pesticides, heavy metals, and chemicals
Outlook: Long-Term Monitoring of Sperm Quality
Regulatory bodies like the WHO and independent research teams continue to monitor for possible late effects. To date, there is no indication of long-term damage, as vaccines do not alter germ cells.
Practical Tips: Semen Analysis & Fertility Check
If you want a thorough check of your fertility, consider a semen analysis about three months after completing your vaccination series. Since sperm maturation takes around 72–90 days, this reflects your current sperm quality.
- Preparation: Abstain from ejaculation for 2–7 days before sample collection.
- Lab Selection: Choose an accredited andrology or urology center for reliable results.
- Regular Monitoring: If you’re facing infertility issues, repeat testing every six months.
- Consultation: A urologist or andrologist can interpret results and recommend interventions like lifestyle changes or hormone therapy.
References & Further Reading
- Gonzalez DC et al. Sperm Parameters Before and After COVID-19 mRNA Vaccination. JAMA 2021.
- Chen YX et al. Effects of SARS-CoV-2 Vaccines on Sperm Quality: Systematic Review. JMIR Public Health Surveill 2023.
- Yuan L et al. COVID-19 Infection Was Associated with Poor Sperm Quality. Scientific Reports 2025.
- CDC: COVID-19 Vaccination for Those Planning Pregnancy. 2024.
Conclusion
Scientific evidence shows that COVID-19 vaccines do not cause lasting impairment of sperm quality. Much more important are a healthy lifestyle, effective stress management, and regular check-ups. For personalized advice, consult a urologist or andrologist.