mRNA COVID-19 Vaccines Show No Impact on IVF Success Rates

By Brandon May

March 21, 2022

NEW YORK (Reuters Health) - mRNA COVID-19 vaccines do not appear to affect the outcomes of in vitro fertilization (IVF), a new study from Israel finds.

There has been concern over a possible detrimental effect given the similarity between syncytin-1, a human placental fusion protein, and the SARS-CoV-2 spike protein expressed after administration of the COVID-19 vaccine, say Dr. Sarit Avraham of Shamir Medical Center, in Tzrifin, and colleagues.

To investigate, they studied 200 women between 20 and 42 years of age who underwent IVF treatment at two medical centers in Israel between January and April of 2021.

As reported in Fertility and Sterility, all patients received two doses of an mRNA COVID-19 vaccine at least two weeks prior to starting ovarian stimulation. They were matched by age to 200 unvaccinated women who also underwent IVF treatments during the same months.

There was no significant difference between vaccinated and unvaccinated patients with regard to the average number of oocytes retrieved per cycle (10.6 vs. 10.7).

In "freeze-all" cycles, rates of fertilization (55.4% for vaccinated vs. 54.3% for unvaccinated) as well as average number of cryopreserved embryos (3.6 vs. 3.3, respectively) were not significantly different between the two study groups. There was also no significant difference in fertilization rate between vaccinated and unvaccinated patients who underwent fresh-embryo transfers (64.8% vs. 62.0%, respectively).

Clinical pregnancy rates among 128 vaccinated and 133 unvaccinated patients who underwent fresh-embryos transfers were 32.8% and 33.1% (P=0.96), respectively, and chemical pregnancy rates were 4.7% and 9.8% (P=0.11).

In regression models, the researchers found no effect of the COVID-19 vaccine on oocyte yields and rates of pregnancy.

While the study's retrospective design is a limitation, the researchers feel that the "sample size was sufficient to control" for this.

Dr. Raoul Orvieto, director of the IVF Unit at Sheba Medical Center in Tel Aviv, who was involved in the study but is not listed as an author on the paper, said he and his colleagues have looked at "all aspects of COVID-19 and its relation to fertility."

"We first started with whether the virus has any effect on IVF and noticed a small decline in the number of embryos, but that effect seems to wear off after 3 months," he told Reuters Health by email.

Dr. Jennifer Kawwass, medical director of Emory Reproductive Center in Atlanta, said the results are "reassuring" and add to the "growing body of evidence" that COVID-19 vaccines do not impact fertility.

"Evidence continues to support the recommendations of American College of Obstetricians and Gynecologists, Society for Maternal-Fetal Medicine, and American Society for Reproductive Medicine regarding the importance of encouraging COVID-19 vaccination to all patients, including those considering conception and those who are pregnant or postpartum," she told Reuters Health by email.

"Unfortunately, there have been myths and mistruths regarding COVID-19 vaccination and fertility that have contributed to vaccine hesitancy," said Dr. Kawwass, who wasn't involved in the new study. "The findings from the study add to the growing evidence debunking these myths and supporting vaccine safety."

She added that other "areas for research include whether and when vaccination should be repeated during pregnancy to add additional fetal immunity, the impact of the vaccine on a cellular level on reproductive tissues, and further long-term data regarding vaccination and fertility."

The researchers reported no conflicts of interest or study funding.

SOURCE: https://bit.ly/3vRTK45 Fertility and Sterility, online February 24, 2022.

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