No adverse effect on sperm quality 6-14 months after BNT162b2 COVID vaccine

A study published in the journal Gamete biology It shows that the mRNA 2019 (COVID-19)-based coronavirus vaccine developed by Pfizer/BioNTech does not harm sperm health over a long period after vaccination.

​​​​​​Stady: Sperm quality is not affected by the BNT162b2 mRNA SARS-CoV-2 vaccine: 6-14 month follow-up results.. Image Credit: Yurchanka Siarhei / Shutterstock


Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes COVID-19, enters host cells through the interaction between the viral spike protein and the host cell receptor angiotensin-converting enzyme 2 (ACE2).

The presence of ACE2 on the blood-testicular barrier makes the male reproductive system more susceptible to infection with SARS-CoV-2. In this context, some studies have shown that SARS-CoV-2 may slightly affect sperm quality within two to three months after infection. However, the majority of studies looking at SARS-CoV-2-induced changes in the male reproductive system have not been able to detect viral RNA in semen.

Studies looking at the effect of the COVID-19 vaccine on sperm health have shown that the vaccines are safe for use in men. However, most of these studies have only examined the short-term effects of the COVID-19 vaccine. Analysis of long-term outcomes is particularly needed to increase vaccine uptake and reduce vaccine frequency among men.

In the current study, scientists evaluated the effect of the mRNA-based COVID-19 vaccine (Pfizer/BioNTech) on sperm quality six months and 14 months after vaccination.

study design

The study was conducted on 58 men who were undergoing in vitro fertilization (IVF) treatment and received two or three doses of the Pfizer/BioNTech COVID-19 vaccine. The study included men with poor sperm quality prior to vaccination. In addition, none of the participants had a history of SARS-CoV-2 infection.

Semen samples were collected from participants before vaccination (baseline) and 6 to 14 months after vaccination. Samples were analyzed for semen volume, total number of motility, sperm concentration, motility, and morphology.

Important notes

Of the 58 men included in the final analysis, 16 had abnormal sperm quality, and 42 had normal sperm quality at baseline. The average age of the participants was 38 years. The average time between vaccination and semen analysis is 317 days.

Specifically, semen analysis was performed 6–9 months and 9–14 months after vaccination in 13 and 45 participants, respectively. Considering the entire study population, higher and lower kinetic counts were observed after vaccination in 27 and 28 men, respectively.

Analysis of semen samples before and after vaccination showed no significant differences in any of the parameters tested, including semen volume, total motility, sperm concentration, morphology, and motility.

Both men who received the two- and three-dose vaccination showed the same sperm health after vaccination except for sperm concentration, which showed higher levels in the men who received the three-dose vaccination.

No significant difference in sperm health after vaccination was observed between men with normal and abnormal sperm parameters before vaccination. Furthermore, no association was observed between time since vaccination and sperm health after vaccination.

Study the importance

The study highlights that the mRNA-based COVID-19 vaccine (Pfizer) is safe for use in men. The vaccine does not appear to impair the male reproductive system over a relatively long period. Furthermore, the safety profile does not appear to depend on the number of vaccine doses or sperm quality prior to vaccination.

As mentioned by the scientists, the study includes male infertile men, which may limit the applicability of the findings to the general population.​