There is a rumour circulating on the internet that the vaccination against the coronavirus could make women infertile.
Bildrechte: BR/Julia Müller

There is a rumour circulating on the internet that the vaccination against the coronavirus could make women infertile.

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No evidence of infertility caused by corona vaccination

There is a rumour circulating on the internet that the vaccination against the coronavirus could make women infertile. A #Faktenfuchs fact check on why various experts think this is very unlikely.

A lot of rumours and allegations about possible side effects of the vaccines against the SARS-CoV-2 virus are spreading. The #Faktenfuchs has already checked some of them and refuted, among other things, claims that the human DNA is changed by the vaccine.

The claim that vaccination against Covid-19 can make women infertile also keeps emerging on the internet. "A friend of mine who urgently wants to have children doesn't want to be vaccinated because she read that the vaccine makes her infertile", a Twitter user writes and asks: "Does anyone here know more (preferably well-founded and not turgid)?"

Petition to the European Medicines Agency (EMA)

In a petition to the EMA written by people who are trying to downplay corona, the point about possible infertility is included. The petition does not say that the vaccine causes infertility, but that it has not been proven that it does not. The vaccine, according to the claim, could trigger an immune reaction that is not only directed against the coronavirus but also against a protein involved in the formation of the placenta in the uterus. But how could such a reaction occur?

The central role of the spike protein

The SARS-CoV-2 virus has so-called spike proteins. These are - metaphorically speaking - the spikes around the virus. Through these spike proteins, the virus docks onto human cells and can infect them. The human immune defence is directed at these proteins. The spike-shaped protein also plays a central role in the development of vaccines. The mRNA vaccines, for example from BioNTech/Pfizer and Moderna, contain the blueprint for individual harmless virus proteins. The human body thus forms the proteins (antigens) itself according to this blueprint, which then cause the immune reaction and the formation of antibodies.

This mechanism forms the background for the claims about the influence on fertility: the vaccine could not only trigger a defence reaction against the SARS-CoV-2 virus, but perhaps also against the protein Syncytin-1, which is an essential prerequisite for the formation of the placenta. Both spike proteins and Syncytin, according to the claim, contained similarities. It had to be ruled out, the petition said, "that a vaccine against SARS-CoV-2 triggers an immune reaction against Syncytin-1, as otherwise infertility of indeterminate duration in vaccinated women could be the consequence".

Marion Kiechle: "A false allegation"

Marion Kiechle, director of the gynaecological clinic at the hospital "Klinikum rechts der Isar" in Munich, member of the Leopoldina academy and former minister in Bavaria, comes to the following conclusion regarding this suspicion: "In my estimation, it is a false claim, as there is no scientific evidence for it or even the slightest indication that the currently approved vaccines have a negative impact on female fertility."

This refers to the mRNA vaccines approved in several countries, such as those from Biontech/Pfizer and Moderna, and also applies to DNA-based vaccines.

The protein Syncytin-1 and the spike protein of the coronavirus have, as Kiechle explains, only a very small commonality, making an immune reaction against Syncytin-1 "highly unlikely". In addition, there is no evidence of infertility in vaccinated women in the clinical studies on the vaccines.

From a clinical point of view, the following fact also speaks against the claim: "In the USA alone, more than 40,000 cases of corona-positive pregnant women have been published", Kiechle explains. These women also formed antibodies against the spike protein of the coronavirus as a result of the infection - as happens after a vaccination. "If these antibodies also attacked Syncytin-1, a very high rate of miscarriages and pregnancy complications would have been expected", the physician explains, "and this was/is precisely not the case."

Researchers at the University of Jena: young women's concerns unfounded

Researchers at the University of Jena confirm Kiechle's assessment. Ekkehard Schleußner, director of the Department of Obstetrics at the University of Jena, explains: If the corona vaccination would make a woman infertile, then a corona infection should do so even more. "In the case of an infection, the antigen load of the patient through the corona spike protein and thus the potential antibody formation is significantly higher and more incalculable than in the case of a vaccination", Schleußner says in a press release of the University of Jena. "Our previous experience with pregnant women suffering from corona does not confirm this."

The Robert-Koch-Institute also points this out in its FAQs on the efficacy and safety of the corona vaccine. During the pandemic caused by the Sars-CoV-1 virus in 2002/2003, no infertility was observed in women after infection - although the observation period is now almost 20 years. This was stated by Udo Markert from the placenta laboratory in Jena in an interview with SWR.

Biontech: Amino acid sequence too short to cause autoimmunity

The vaccine manufacturer Biontech also rejects the claim when asked by #Faktenfuchs. "This is not correct", the communications department of the Mainz-based company says. "There is no data to suggest that Pfizer-BioNTech's vaccine causes infertility." And: "The sequence is (...) too short - four common amino acids - to plausibly cause autoimmunity", the Biontech company spokeswoman explains.

The vaccination myth of infertility

The myth that vaccination makes people infertile has been spread in various forms for a long time. Already at the beginning of the pandemic, Microsoft founder Bill Gates was accused of wanting to decimate the population through vaccination. And for years the rumour has been circulating that the WHO wanted to forcibly sterilise women in Kenya, among other places, by adding the pregnancy hormone beta-hCG to a tetanus vaccination. The ARD fact finder has already refuted this.

Vaccines always have risks

No vaccine is completely free of risks. As with other vaccines, temporary side effects such as headaches, fatigue, pain in the area where the vaccine was administered, chills or fever can occur. Such side effects are common with vaccinations, as Stefan Kaufmann, director emeritus at the Max-Planck-Institute for Infection Biology, explains: "It doesn't work completely without them." A temporary inflammatory reaction is nothing negative at first. After all, the body needs to know where to go with its immune response, Kaufmann says.

On December 21, the EU Commission approved the vaccine from Biontech/Pfizer. The condition is that the manufacturers also provide data on long-term effects in all 27 EU member states to the European Medicines Agency. Data on possible side effects or allergic reactions will also continue to be collected and examined.


The myth that vaccination makes one infertile has been circulating in various cultures for a long time, including during the corona pandemic. The claim that an mRNA vaccine against the coronavirus could also trigger a defence reaction against a placental protein is rejected as a false claim by both the scientist Marion Kiechle, director of the gynaecological clinic at TU Munich, and the manufacturer Biontech. The similarities of the two proteins are too little to cause the defence reaction.

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