Numerous posts have falsely claimed that mRNA vaccines used against COVID-19 focus on a protein called syncytin-1, which is necessary for the formation of placenta and successful pregnancies. Many of these posts also imply that the vaccines will make people infertile. These allegations are untrue; no available mRNA vaccines target a protein called syncytin-1.
One such report (here) reads: ‘The mRNA-vaks is targeted to a protein called Syncitin-1, which is a protein found in the CV spike-protein complex.
‘THE PROBLEM is that there is no mechanism to eliminate or stop the destruction of Syncitin-1, which also occurs in the BRAIN and female reproductive system. Therefore, Syncitin-1 will be removed in the body. Without Syncitin-1, no placenta can form. The brain manifestations of no Syncitin-1 are MS, Parkinson’s, schizophrenia, psychopathy and I am positive; any neurodegenerative condition. ” [sic]
The Pfizer / BioNTech and Modern COVID-19 vaccines work by inserting mRNAs that tell human cells to produce a series of amino acids that form a protein, such as the “spike protein” found on the SARS-CoV -2 virus causing COVID-19. The mRNA is then destroyed (here).
The goal is for the immune system to recognize and eliminate this protein so that it is willing to target the same structure to the virus if it encounters an intact SARS-CoV-2.
The allegations that these mRNA vaccines will attack the immune system to syncytin-1 are unfounded. Syncytin-1 is not contained in the SARS-CoV-2 ear protein and the SARS-CoV-2 ear protein and syncytin-1 are not very similar.
Pfizer spokeswoman Dervila Keane confirmed in previous emails (here) to Reuters that the protein targeted by their vaccine shares only a series of four amino acids with syncytin-1, which is too short to have problems with cause autoimmunity. Syncytin-1 here consists of 538 amino acids).
“Since there are only 20 different types of amino acids, it is not surprising that many, many proteins have similarities,” wrote Catherine Thornton, a professor of human immunology at Swansea University (here), and April Rees, a PhD Researcher in Immunology at Swansea University in an article on the topic for publication here.
Numerous experts have confirmed that there are few similarities between the COVID-19 ear protein and syncytin-1 and that it was not significant enough to confuse the immune system between the two (here and here and here and here and here).
Some pointed out that the same immune response caused by the mRNA vaccine response would be seen in pregnant women who contracted COVID-19, and that there was no evidence of increased miscarriages in the hospital or disorders in the group (here and here and here).
VERDICT
Untrue. Syncytin-1 is not part of the SARS-CoV-2 ear protein. There is no evidence that mRNA vaccines for COVID-19 have a negative effect on female fertility.
This article was produced by the Reuters Fact Check team. Read more about our work to actually check social media posts.