Study suggests COVID-19 vaccines do not reduce fertility

The FDA-approved COVID-19 vaccines are effective in preventing infection and serious illness. Yet many Americans who are eligible for the vaccines have chosen not to get them. Many report concerns about possible side effects. For adults aged 18-39 years, potential effects on fertility are a particular concern. So far, studies have found no link between COVID-19 vaccination and fertility. However, there is evidence that SARS-CoV-2 infection can temporarily reduce fertility.

A research team led by dr. Amelia Wesselink at Boston University School of Public Health investigated the relationship between COVID-19 vaccination, SARS-CoV-2 infection and fertility. They analyzed data from an Internet-based pregnancy study that followed American and Canadian couples trying to conceive over time. NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) funded the study. Results appear in the American Journal of Epidemiology on January 20, 2022.

For their analysis, the team followed more than 2,000 women, aged 21-45, from December 2020 to November 2021. Everyone has tried to get pregnant without fertility treatments. Participants answered questions about income, education, lifestyle, and reproductive and medical histories. This included questions about COVID-19 vaccine status and positive SARS-CoV-2 tests. The women also provided information about their partners’ vaccine status and positive tests. Male partners aged 21 and over were invited to answer similar questions. Female partners completed follow-up questionnaires every 8 weeks for up to 12 months or until they became pregnant.

The team found that the chances of conception did not change with either partner’s vaccination status. The researchers adjusted for several factors that could affect the results. These included the type of vaccine, nationality, occupation and history of infertility. This did not affect the results.

The overall chances of conception were not associated with previous SARS-CoV-2 infection in either partner. However, the team found that conception during a given menstrual cycle was less likely if the male partner had tested positive up to 60 days earlier.

“Our study shows for the first time that COVID-19 vaccination in either partner is not related to fertility among couples trying to conceive through intercourse,” says Wesselink. “Time to pregnancy was very similar regardless of vaccination status.”

Previous studies have shown that SARS-CoV-2 infection during pregnancy, on the other hand, can pose risks to both mother and baby. Pregnant women with moderate to severe COVID-19 may face a higher risk of death or serious illness from complications. Their babies may also be at greater risk of premature birth, stillbirth or newborn death. Vaccination can help prevent these risks.