As the first weeks of the Covid-19 vaccines are wrapping up, many who’ve received it, be it the one manufactured by Pfizer-BioNTech or Moderna, have posted selfies while getting their shots on social media, and are offering play-by-play details of any side effects. Most vaccine recipients, who have primarily been healthcare workers during these early weeks of vaccine distribution, have reported some arm soreness for a day. Some reported fevers, chills, fatigue, and headache, also for a day or less. There have been rare cases of severe allergic reactions, but even those were addressed and treated. For the vast majority, these minor symptoms pale in comparison to the feelings of elation, optimism, relief and vision of the beginning of the end of the pandemic.
Pictured below is Dr. Paul Offit, Infectious Disease Specialist and Virologist at the Children’s Hospital of Philadelphia, receiving his Covid-19 vaccination.
But those who are trying to conceive, or considering pregnancy and/or in vitro fertilization (IVF) have concerns that the vaccines could impact fertility or lead to fetal loss. This concern has morphed into a whirlwind of social media lore that the vaccine should not be given to women considering conception. How could a vaccine preventing a respiratory illness lead to infertility? Well, it won’t, but several falsely-claiming social media posts purported a link between the spike protein formed by receiving the mRNA-based vaccines and blockage of a protein necessary for formation of and adherence to the uterus of the human placenta. Using scientific terms like the specific name of the protein, syncitin-1, placenta, antibodies, and sterilization, false claims sounding like science became science fiction quite quickly.
The protein syncitin-1 is critical for the placenta to remain attached to the uterus and act as the source of nutrition and blood supply to the fetus during pregnancy, but this is not the protein known as the Covid-19, or SARS-CoV-2, spike protein. The two share a few similar amino acids, but they are not the same proteins. At all. The antibodies produced against the Covid-19 spike protein will not block syncitin-1. While the Covid-19 spike protein shares several amino acids in common with syncitin-1, it is not similar enough (in fact, it’s not even close to similar enough) for the antibodies to recognize and block this critical placental binding protein.
During the Pfizer-BioNTech vaccine study, there were 23 study participa