As news of a coronavirus vaccine neared, questions and misinformation began surfacing about whether or not the vaccine could lead to fertility issues in women.
The concerns were sparked by an article spreading on social media, which experts have said includes false information, but many say there is still more research needed surrounding the vaccine and pregnancy.
Dr. Gregory Huhn, an infectious diseases attending physician and the Vaccination Coordinator for COVID-19 at Cook County Health, said there's currently no "suggestion that [the vaccine] could affect future fertility," but said the lack of data poses a challenge.
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According to Illinois and U.S. medical experts, pregnant women were excluded from trials for the vaccine, leading some to recommend against vaccination for women who are pregnant or planning to be pregnant within three months of receiving their doses - until further testing can be conducted.
"We don't have any information actually in pregnancy. Women who were in the trial who became pregnant were removed from the trial so we can't give any information about pregnancy," said Illinois Department of Public Health Director Dr. Ngozi Ezike.
Ezike said that while people planning fertility may be advised against receiving the vaccine, she has not heard of "any adverse effects causing fertility issues for the people who got it."
According to the Centers for Disease Control and Prevention, if a woman is part of a group recommended to receive a COVID-19 vaccine and is pregnant, she may choose to be vaccinated. A discussion with her healthcare provider can help her make an informed decision, the agency stated.
"There's a lot of conversation and controversy and advocacy around what to do with women who are pregnant or may become pregnant or breastfeeding," said Dr. Allison Bartlett, associate professor of pediatric infectious diseases at the University of Chicago. "And it's a really interesting issue because pregnant women were excluded from the study. And we understand because we sort of treat pregnant women as a special class, but so much of our health care workforce and our other frontline workers are women of childbearing age that to deny them the ability to get the vaccine just because we don't know is really putting them at a disadvantage."
Huhn said it is common that pregnant women aren't included in early trials for new vaccines.
Some social media users have been sharing a screenshot from an article titled “Head of Pfizer Research: Covid Vaccine is Female Sterilization” to claim the vaccine results in sterilization of women. The head of research at Pfizer has made no such claim, however.
Information in the article, carried by the blog “Health and Money News,” is attributed to Michael Yeadon, a retired British doctor who left Pfizer nine years ago.
The article, which doctors have said includes false claims, says “the vaccine contains a spike protein called syncytin-1, vital for the formation of human placenta in women.” It goes on to say “the vaccine works so that we form an immune response AGAINST the spike protein, we are also training the female body to attack syncytin-1, which could lead to infertility in women of an unspecified duration.”
Pfizer spokeswoman Jerica Pitts confirmed to The Associated Press that their vaccine candidate has not been found to cause infertility.
“It has been incorrectly suggested that COVID-19 vaccines will cause infertility because of a shared amino acid sequence in the spike protein of SARS-CoV-2 and a placental protein,” she said in an email. “The sequence, however, is too short to plausibly give rise to autoimmunity.”
Experts also say there is no evidence that the Pfizer vaccine would result in sterilization of women.
Rebecca Dutch, chair of University of Kentucky’s department of molecular and cellular biochemistry, said in an email that while syncytin-1 and the spike protein broadly share some features, they are quite different in the details that antibodies recognize.
Aside from the fact that COVID-19’s spike protein and syncytin-1 are viral fusion proteins that cause membrane fusion, they are not related at all, Dutch said.
Additionally, the vaccine being developed by Moderna, like the one being developed by Pfizer and BioNTech, relies on messenger mRNA, which tells the body how to make the spike protein and trains the immune system to identify the real virus. They do not contain syncytin-1.
"The protein that is manufactured by our immune system is a fragment of what's called the spike protein, which is the part of the virus that attaches onto the receptors on cells," Huhn said. "But that protein is not attached to anything related to any form of what we know is that causes disease and infection with the natural virus. And so, just with that small fragment of the spike protein particle that again, is manufactured as a protein that's recognized by our immune system, I do not believe that we would have any suggestion that it could affect future fertility."