Concerns about the COVID-19 vaccine causing infertility have circulated globally. This article examines the scientific evidence regarding the vaccine’s impact on fertility, providing important facts for those considering vaccination, especially when planning to conceive.
Scientific Evidence on Fertility
Extensive research and leading health organizations consistently show no evidence that COVID-19 vaccines cause fertility problems in men or women. Organizations like the CDC, ACOG, and ASRM recommend vaccination for individuals who are pregnant, breastfeeding, or trying to conceive.
Studies on male fertility, including sperm count, motility, and morphology, have found no adverse effects after vaccination. For women, research indicates that COVID-19 vaccines do not negatively affect ovarian function, egg quality, or IVF success rates. Pregnancy success rates have been similar in vaccinated women. While some women have reported temporary changes to their menstrual cycle, such as a slight delay or heavier bleeding, these changes are generally small, short-lived, and do not indicate infertility. These transient menstrual variations are not uncommon after other vaccinations, suggesting a temporary immune response. Studies have found no increased risk of miscarriage, stillbirths, or birth defects in vaccinated pregnant individuals.
Vaccine Mechanism and Reproductive Health
The mechanism of COVID-19 vaccines provides a biological basis for why they do not impact fertility. mRNA vaccines deliver genetic instructions to cells, prompting them to produce a harmless piece of the SARS-CoV-2 spike protein. This triggers an immune response, teaching the body to fight the virus.
The vaccine’s spike protein is distinct from syncytin-1, a protein important for placental development, and antibodies produced against it do not cross-react with syncytin-1. Vaccine components do not enter or alter DNA within reproductive cells. The genetic material is processed and eliminated by the body’s cells, and the immune response is localized and temporary. There is no biological pathway through which the vaccine could cause long-term changes to reproductive organs or function. This temporary immune activation is a normal response, designed to build protective immunity.
COVID-19 Illness and Reproductive Health
In contrast to the vaccine, a COVID-19 infection can notably impact reproductive health. Severe COVID-19 illness, characterized by fever and widespread inflammation, has been linked to temporary declines in male fertility. The virus can affect sperm quality, including concentration, motility, and morphology, and may cause testicular damage. While these effects are often temporary, the virus’s direct impact is a recognized concern.
For women, severe COVID-19 illness during pregnancy has been associated with increased risks of adverse outcomes. These include a higher likelihood of pre-term birth, stillbirth, preeclampsia, and other complications, particularly with symptomatic or severe infections. Pregnant individuals with COVID-19 are also more prone to severe illness, hospitalization, and intensive care unit admission. These risks underscore the importance of preventing COVID-19 infection, which vaccination helps to achieve.