A pregnant person receiving a COVID-19 vaccine in in Lipetsk, RussiaShare on Pinterest
A pregnant person receiving a COVID-19 vaccine in Lipetsk, Russia. Alexander RyuminTASS via Getty Images
  • Some reproductive-aged individuals are concerned about the potential adverse effects of COVID-19 vaccination on their ability to conceive.
  • Some earlier research has concluded that COVID-19 vaccinations do not appear to reduce fertility.
  • A new study adds to this evidence, finding that the vaccines do not affect fertility in males or females.
  • However, SARS-CoV-2 infection in males does seem to have short-term effects on fertility.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub for the most recent information on the COVID-19 pandemic.

Although scientists have shown that COVID-19 vaccines are safe and effective, vaccine hesitancy persists. A wide range of myths and misconceptions play a part in this hesitancy, one of which is a fear that the vaccines reduce fertility.

Researchers from the Boston University School of Public Health recently set out to investigate this concern. They concluded that vaccination — in both males and females — does not appear to affect fertility.

The study, which appears in the American Journal of Epidemiology, also examines the effects of SARS-CoV-2 infection on fertility.

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Safety is an important factor in deciding whether to receive a COVID-19 vaccination. One of the most common reasons for choosing to remain unvaccinated is concern regarding possible side effects. This is especially true for those wishing to become pregnant.

As the authors of the new study explain, limited data are available on the association between COVID-19 vaccination and fertility in females. Even less evidence exists on the possible effects of vaccination on male fertility.

To help fill this gap, the scientists took data from an internet-based preconception cohort study called Pregnancy Study Online, or PRESTO.

The study recruited 2,126 people from December 2020 until November 2021. Eligible participants resided in the United States and Canada and self-identified as females between 21 and 45 years of age who were trying to conceive without the use of fertility treatments.

The researchers gave the participants the option of inviting their male partners to participate in the study. All participants completed a baseline questionnaire that included information about sociodemographics, lifestyle, and reproductive and medical histories. The females filled out follow-up questionnaires every 8 weeks for up to 12 months.

The data from PRESTO showed that the fertility rates among female participants who had received at least one dose of a COVID-19 vaccine were nearly identical to those of unvaccinated female participants. The results were similar for their male partners.

“Our findings that COVID-19 vaccination was not related to fertility are consistent with other studies from couples undergoing fertility treatment,” Amelia Wesselink, lead author of the study and a research assistant professor of epidemiology at Boston University, said in an interview with MNT. She continued:

“The evidence on this issue is growing, and everything so far indicates that the COVID-19 vaccine is not causing infertility.”

William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center in Nashville, TN, spoke with MNT about the Boston University study.

“This study clearly confirms the message and the other data out there saying that the vaccines do not predispose to any difficulty with fertility,” said Prof. Schaffner.

The study also investigated male fertility in relation to the vaccine and SARS-CoV-2 infection. Although the team found no associations with the vaccine, the data did show a short-term decline in male fertility after SARS-CoV-2 infection.

The authors note that previous research has shown fever to affect sperm concentration and motility after any infection. As fever is a common symptom of COVID-19, this could explain the decline in male fertility after a recent SARS-CoV-2 infection.

“Regardless, we did not observe any association between SARS-CoV-2 infection and fecundability that persisted beyond 60 days,” said the researchers.

The authors note several strengths to their study, including a large number of participants from geographically and socioeconomically diverse populations.

The study’s limitations include a reliance on self-reporting of infection and vaccination status. Also, as the authors note, “for couples in which the male partner did not complete his questionnaire, we relied on female report of male vaccination status.”

When MNT asked Prof. Schaffner what further research is necessary, he explained: “As we go forward and develop other new vaccines — updated COVID-19 vaccines and any others that involve reproductive-age adults — fertility is an issue that needs to be addressed. It will come up again with other vaccines.”

Wesselink agreed and added: “We definitely need to know more about the effects of COVID-19 itself on reproductive health. In our study, for instance, we didn’t have data on symptoms or severity of infection, so research investigating how these factors correlate with reproductive function is warranted.”

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