(NBC News) - Worries that the Covid-19 vaccine could cause infertility are among the reasons people give for avoiding vaccination. While there’s no evidence any of the Covid vaccines cause problems with fertility, becoming severely ill from the disease has the potential to do so, reproduction experts say, making vaccination all the more important.
“There is evidence to suggest that infection with SARS-CoV-2 has the potential to impact both male fertility, female fertility, and certainly the health of a pregnancy of someone infected,” said Dr. Jennifer Kawwass, a reproductive endocrinologist and associate professor at the Emory University School of Medicine in Atlanta. “And there is simultaneously no evidence that the vaccine has any negative impact on male or female fertility.”
Researchers have been studying the effects of Covid on the human reproductive system since the beginning of the pandemic. While there’s no evidence that Covid can be sexually transmitted, research suggests that the cells in the reproductive system are feasible targets for the virus, because they carry some of the receptors the coronavirus must bind to in order to enter cells.
The idea that a virus could cause infertility is not unprecedented. “We do have historic evidence that there are certain viruses that are more likely to impact either male or female fertility,” Kawwass said.
For example, human papillomavirus (HPV), hepatitis B, hepatitis C and HIV infections have all been linked to decreased fertility. It’s unclear, however, if a respiratory virus, like the coronavirus, could have the same effect. But the fact that male and female reproductive organs have the receptors the Covid virus targets means it’s certainly plausible that the virus could cause fertility issues, she said.
Moreover, the symptoms of Covid — primarily fever higher than 102 degrees Fahrenheit for at least three days — are known to cause fertility issues, especially in men.
According to a recent review paper published in the journal Reproductive Biology, moderate to severe Covid infections have caused decreased sperm count, testicular inflammation, sperm duct inflammation and testicular pain in men of reproductive age. Although not considered common complications of Covid in particular, these effects are often associated with reduced fertility, and are enough to lead scientists to hypothesize that Covid may cause fertility issues in men, warranting further research in this area.
Dr. Eve Feinberg, a reproductive endocrinologist and associate professor at Northwestern University, works with patients with fertility issues every day. She said although she doesn’t think the virus itself directly leads to infertility, she’s noticed that some of her male patients have experienced infertility due to low sperm counts after having Covid. “But, it’s too early and very hard to say whether or not they had a low sperm count prior to Covid infection,” she added.
The symptoms of the disease, rather the virus itself, may be the culprit when it comes to causing fertility issues.
“Any infection, particularly an infection that involves fever, can affect sperm production and can affect ovulation,” said Dr. Marcelle Cedars, reproductive endocrinologist and director of the University of California, San Francisco, Center for Reproductive Health. There’s no evidence that Covid would be different from that, she said.
Most of the research on Covid and its effects on fertility have focused on men, but the few studies in women have found that neither the virus nor its symptoms seem to have a major impact on menstruation or hormone cycles.
An analysis of more than 230 women of childbearing age found that although sex hormone levels changed and menstruation cycles shifted when they were infected with the coronavirus, the changes were insignificant compared to the control group. The Covid patients’ cycles returned to normal within days or weeks of the infection clearing, and it’s unlikely there was any effect on fertility.
But fertility doesn’t end with a viable sperm and egg, at least in the eyes of a fertility doctor. “When I think about fertility, I think about what is the likelihood that a couple will take home a healthy baby,” Feinberg said. “And there is no question in my mind, or any scientist’s mind, that the highest likelihood of having a healthy baby during this pandemic is by getting vaccinated.”
The vaccine does not decrease fertility, nor does it negatively affect reproduction, but there is very clear evidence that getting Covid whilepregnant is incredibly dangerous, Kawwass said. “Pregnant women with symptomatic Covid-19 have a 70 percent increased risk of death compared to nonpregnant women with Covid,” she said.
The latest data from the Centers for Disease Control and Prevention estimated that only 31 percent of pregnant women in the United States are vaccinated against Covid.
The low vaccination rate among pregnant women is a public health crisis, Feinberg said. That has her wondering if fertility clinics may eventually be forced to limit or turn away patients because of the substantially increased health risk unvaccinated pregnant women have compared with their vaccinated counterparts. At this point, unvaccinated patients seeking in vitro fertilization are not denied treatment, but that could change if circumstances don’t improve. There are many unvaccinated pregnant patients with Covid who are in the intensive care unit, she said, recalling that one of her unvaccinated Covid patients lost her baby while in the ICU. “It was devastating and entirely preventable.”
Doctors have long recommended that people who are trying to conceive get several vaccines if they haven’t already, such as the flu and chickenpox vaccines. While many illnesses may cause infertility, there are no vaccines that cause fertility issues.
And the evidence to date shows the Covid vaccine is no different than all the other vaccines that doctors recommend for individuals who are considering pregnancy, Cedars said. Doctors aim to do everything they can to help patients conceive and prepare for a healthy pregnancy, she said, and the Covid vaccine is “just part of that.”