Around the time that COVID-19 vaccines were first rolling out, Alice Lu-Culligan felt compelled to help set the record straight. Baseless rumors were sowing confusion and vaccine hesitancy.
In a New York Times opinion piece published in January 2021, the MD-PhD candidate at Yale School of Medicine and her scientific mentor, immunobiologist Akiko Iwasaki, PhD, challenged one false narrative. The rumor spreading on social media claimed that mRNA vaccine-induced antibodies against the SARS-CoV-2 spike protein could attack a placental protein called syncytin-1, causing infertility.
Not only were there no data to support the idea, but it was highly implausible, Lu-Culligan explained in a recent interview with JAMA. The notion also appeared disingenuous, she said: if exposure to the spike protein caused infertility, natural infection with SARS-CoV-2 would too—but no one was claiming that.
After conducting analyses to test the claim, she and Iwasaki concluded it was false. Days later, the American College of Obstetricians and Gynecologists, the American Society for Reproductive Medicine (ASRM), and the Society for Maternal-Fetal Medicine published a joint statement assuring “patients that there is no evidence that the vaccine can lead to loss of fertility.”
As she was writing her op-ed piece, Lu-Culligan noticed that Google and Facebook were removing misinformation-peddling links from browser searches and pulling down social media posts promoting the syncytin-1 falsehood. But different variations on the infertility theme continued to pop up “like Whac-A-Mole,” she said.
A 2021 report by NewsGuard, an online service that rates the reliability of news and information websites, identified several false claims related to COVID-19 vaccines and fertility and reproduction. In addition to the syncytin-1 myth, the vaccines were falsely claimed to cause infertility in 97% of women; to increase miscarriage risks; and, in males, to negatively affect the testicles, the prostate, and testosterone levels.
Tara Kirk Sell, PhD, a senior scholar at the Johns Hopkins Center for Health Security, called this particular brand of misinformation part of “active efforts to try to undermine vaccination efforts by highlighting fears that people may have.” In interviews, Sell and others said the false information has been spread through social media platforms, blog posts, cable news, text message chains, and simply by word of mouth.
In October 2021, almost a third of 1519 US adults in a nationally representative survey by KFF, formerly the Kaiser Family Foundation, reported that they heard that COVID-19 vaccines caused infertility and either believed the myth was true or weren’t sure. About a third of pregnant adults in the US remained unvaccinated as of early February 2022, according to the Centers for Disease Control and Prevention (CDC) COVID Data Tracker’s weekly statistics.
“Misinformation about COVID-19 vaccines impacting fertility has been one of the most persistent myths during this pandemic,” US Surgeon General Vivek Murthy, MD, MBA, told JAMA in an emailed statement. “Wide-spread misinformation has unfortunately led many people not to get vaccinated,” Murthy said, “and it has led to alarmingly low rates of vaccination amongst pregnant people, who are actually at greater risk of adverse outcomes with COVID-19 compared with people who are not pregnant.”
As the syncytin-1 rumor went viral on social media, soon friends on parent blogs, Yale classmates, and family from all stages of life were asking Lu-Culligan if it was true. The reference to the protein struck her and others as dubious. Although the SARS-CoV-2 spike protein and syncytin-1 both are surface proteins involved in cell fusion, the latter is derived from endogenous retroviruses, elements in human DNA leftover from ancient viral invasions into the genome.
“To a lot of people, a virus is a virus,” Lu-Culligan said. “But to a virologist, SARS-CoV-2 and an endogenous retrovirus are as different as could be.”
When she and other scientists compared the spike protein to placental syncytin-1, the genetic overlaps were minimal. In a study posted to bioRxiv that has not yet been peer-reviewed, Lu-Culligan and colleagues in Iwasaki’s laboratory found that antisyncytin-1 antibody levels do not increase in the months following COVID-19 vaccination.
Although the claim clearly didn’t check out, Lu-Culligan said certain aspects of the narrative—the fact that syncytin-1 is a real human protein, for example—likely made it appear more credible for some. “One tricky part of this really wild speculation is that there are parts of it that are based in true biology and true science,” she said. “We’ve seen that a tactic that is very effectively employed is to mix misinformation with sprinklings of fact mixed with part truths.”
In an interview, NewsGuard’s health editor, John Gregory, described common COVID-19–era misinformation strategies, such as promoting contrarian views espoused by supposed experts and misrepresenting and then amplifying publicly available complaints. In another tactic, antivaccine advocates have recalculated government data to support their agenda. For people with a mistrust of government, the appearance of digging down into the data to ferret out the truth may validate the idea that officials are hiding something, Gregory said.
In one example he cited, misinformation peddlers manipulated data that appeared in a CDC analysis of the government’s v-safe After Vaccination Health Checker, v-safe COVID-19 Vaccine Pregnancy Registry, and Vaccine Adverse Event Reporting System (VAERS).
The official CDC analysis concluded: “Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA COVID-19 vaccines.” But some posts citing the study said the data demonstrated an 82% miscarriage rate after COVID-19 vaccination. Posts promoting this idea sometimes used a shorthand for vaccination designed to elude factcheckers, according to SciCheck’s COVID-19/Vaccination Project, a feature of the nonprofit, nonpartisan FactCheck.org.
An August 2021 CDC analysis of v-safe Covid-19 Vaccine Pregnancy Registry data found the age-adjusted miscarriage rate to be 12.8%, in line with the typical rate of 11% to 16%. That month, the CDC recommended COVID-19 vaccination for people who were considering conceiving, were pregnant, or were breastfeeding—guidance that still stands.
Claiming that COVID-19 vaccines affect fertility or pregnancy recycles an existing rumor set used by the antivaccine movement, Sell said. Both she and Gregory noted striking similarities in misinformation about COVID-19 vaccines and human papillomavirus (HPV) vaccines. “In some cases,” Gregory said, “you can even call it a sort of Mad Libs misinformation campaign, because all they did was erase ‘HPV vaccine’ and write in ‘COVID.’”
Antivaccination campaigns frequently target women’s reproductive health, noted Eve C. Feinberg, MD, an associate professor of obstetrics and gynecology at the Northwestern University Feinberg School of Medicine and a member of the ASRM COVID-19 Task Force. “It’s a vulnerability that tugs at the heartstrings of a lot of people,” she said in an interview. The fearmongering strategy has reached men, too. Male patients in Feinberg’s fertility clinic ask about the vaccines’ purported effects on sperm count “every day,” she said.
Health professionals are not immune to the rumors. A March 2021 study, for example, found widespread infertility and pregnancy-related misinformation about COVID-19 vaccines among 193 frontline staff in 50 skilled nursing facilities. Early in the vaccines’ rollout, physicians couldn’t definitively say the vaccines were safe in pregnancy because people who were pregnant or lactating were excluded from clinical trials of the products. But now, more than a year later, hundreds of millions of people in the US alone have been vaccinated and worrisome signals for female or male reproductive health have not emerged, according to Joseph Alukal, MD, director of men’s health at Columbia/NewYork-Presbyterian.
Alukal pointed to a study published last year in JAMA that found no significant decreases in sperm counts, semen volume, or sperm motility among 45 men who received a COVID-19 mRNA vaccine. This has been borne out over time, he said in an interview: “We are still performing, for example, fertility medicine around the country, in a population of people who are increasingly vaccinated every month, and we’re not seeing some overall downward trend either in natural conception rates, assisted reproductive success rates, or sperm count parameters.”
In the internet age, misinformation knows no borders. According to Phionah Atuhebwe, MBBS, MPH, the new vaccines introduction officer of the World Health Organization’s Regional Office for Africa, online rumors about vaccine effects on fertility and pregnancy have regularly appeared since the vaccine rollout started, particularly during its early phases.
“The Africa Infodemic Response Alliance [AIRA], an initiative co-hosted by the World Health Organization regional office for Africa, picked up on these rumours through its regular social media listening,” Atuhebwe wrote in an emailed statement to JAMA.
The misinformation is often spread through influencer videos posted to social media platforms. Flipping the script, in May 2021 AIRA released a video through Viral Facts Africa debunking the infertility myths. This past January, KFF released more than 40 short videos in English and Spanish featuring a diverse group of health care workers discussing COVID-19 vaccination, fertility, and pregnancy.
“In the last six months or so, beginning with the emergence of Delta last summer, we started to unfortunately hear more about cases of unvaccinated pregnant people ending up in emergency rooms and hospitals and facing some really severe consequences of COVID, including an increased risk of miscarriage, stillbirth, and even significant health complications for the birthing person,” Tina Hoff, a senior vice president at KFF and director of its social impact media program, said in an interview. “And so there was an increased urgency to reach out to these populations.”
The KFF videos are part of a larger COVID-19 initiative at the organization to reach unvaccinated Black and Latino populations, Hoff said.
According to Rachel Villanueva, MD, a clinical assistant professor of obstetrics and gynecology at the New York University Grossman School of Medicine, the infertility rumors tap into cultural concerns about unethical treatment of Black people, such as the Tuskegee experiment and forced sterilizations that disproportionately affected African American women and other racial and ethnic minority groups. Villanueva, who is president of the National Medical Association, said that fertility-related misinformation in African American communities “has really made it difficult to get vaccination rates up.”
Overcoming patients’ misconceptions about COVID-19 vaccines and fertility “requires a good conversation to understand where their concerns lie, really validate those concerns, and then systematically just go through them one by one and debunk all of them, because there are no facts behind them,” she said in an interview.
Lately, patients frequently tell her they’ve heard that COVID-19 vaccines cause significant and permanent menstrual cycle changes that can lead to fertility problems. Misinformation about menstrual changes is being used to “add new fuel to the claim that COVID vaccines affect fertility,” Gregory said. “It can be used to bolster the older myths.”
While temporary menstrual cycle changes have been reported after COVID-19 vaccination, “it’s really a benign finding, we feel and most of the vast, vast majority of the scientific community feels,” Lu-Culligan said.
Unsurprisingly, the fertility myths have been especially detrimental for COVID-19 vaccine uptake among young adults, noted Ilan Shapiro, MD, MBA, the chief health correspondent and medical affairs officer of AltaMed, a group of federally qualified health centers serving primarily Latino patients in California’s Los Angeles and Orange Counties.
Many patients who never before expressed vaccine hesitancy are choosing to wait on COVID-19 vaccines, Shapiro said in an interview. In some cases, he noted, older parents discourage their adult children from getting the vaccine, fearing it will affect their chances of having grandchildren.
Although he understands patients’ hesitation based on an initial lack of data, misinformation, and mistrust, Shapiro said the time to wait has passed. Discussing the infertility rumors, he said: “Right now, in 2022, we know that we have millions of people already vaccinated—actually half of humanity already has done so—and we have not seen any rates of concern.”
Health misinformation became so rampant during the COVID-19 pandemic that last July Murthy devoted his first Biden administration Advisory to warning the public about it. Last fall, he released a toolkit for health professionals, faith leaders, and other community members to address the threat to public health.
Shapiro and others emphasized that trusted physicians can change patients’ minds and help to halt the spread of misinformation. “That’s, I think, where we need to focus,” he said: “one-to-one conversations, making sure that we teach our community how to read misinformation and classify it, and, most importantly, not to share it and be part of the problem.”
Published Online: February 22, 2022. doi:10.1001/jama.2022.2404
Conflict of Interest Disclosures: Dr Alukal has received payments or stock options for advisory roles with Ezra, Progyny, Inc, and Sandstone Diagnostics, Inc, and an educational grant from Endo Pharmaceuticals. Dr Murthy has had numerous financial relationships with academic, nonprofit, commercial, and governmental entities. Dr Sell is employed by the Johns Hopkins Center for Health Security, which receives funding related to pandemic preparedness research and policy analysis. She also receives funding, grants, honoraria, and payments related to research projects, public speaking, and planning for COVID-19 and misinformation. Dr Shapiro has received compensation from the California Department of Health for consulting on digital communications and from KFF. No other disclosures were reported.