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New Data: Pfizer COVID-19 Vaccine Temporarily Lowers Sperm Count

The data showed overall recovery and no long term negative outcomes


New data from Israeli scientists shows that the vaccine from United States healthcare giant Pfizer, Inc. temporarily impairs semen concentration and total motile count.

The longitudinal multicenter cohort study, first published June 17, examined 220 samples from three different sperm banks. Each donor had received two doses of the vaccine and vaccination was considered completed seven days after the second dose.

Donors were vaccinated between Feb. 1, 2021 and Apr. 16, 2021.

The study had four phases, which included a pre-vaccination baseline control, along with short (15-45 days), intermediate (75-120 days), and long term (>150 days) evaluations. Between one to three semen samples were provided per donor for each phase.

The handling, processing and examinations were all conducted in accordance with World Health Organization (WHO) guidelines. Semen volume was measured by syringe. Then, a drop of native sperm sample was evaluated for concentration.

In the first analysis, no significant change in volume or motility was found within the first 15-45 days. 

However, the results during the intermediate phase showed a 15.4 percent sperm concentration decrease, which led to a total motile count (TMC) reduction of 22.1 percent compared to pre-vaccination levels. TMC is the total number of moving sperm in a sample and can have an impact on one’s chances of successfully generating a natural pregnancy. The researchers said the percentage change reduction was “significantly lower.” 

Long term, the data showed overall recovery and found semen volume and sperm motility beyond 150 days post-vaccination were not impaired. Concentration and TMC in this last phase were reduced, but not in any statistically significant number.

The study, conducted by seven Israeli doctors and scientists specializing in IVF, concluded that systemic immune response after the Pfizer vaccine “is a reasonable cause for transient semen concentration and TMC decline.” But, this decline is temporary, as it is only apparent in the intermediate phase and each donor showed full recovery in the long term.

While there are multiple vaccines and treatments available to treat COVID-19, only the Pfizer vaccine was examined in this study.

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