Widely shared social media posts claim that the Pfizer vaccine causes viral shedding that leads to a disruption of menstrual cycles and possible miscarriages. One viral Instagram video, in particular, includes the following caption: “Pfizer document confirms ‘Covid Vaccine Shedding’ leading to ‘Menstrual Cycle Disruption’ and ‘Miscarriage’ is possible via ‘skin-to-skin contact’ and ‘breathing the same air’.”

The video claims that “the vaccinated seem to be shedding something terrible to the unvaccinated.” The video also says that Pfizer “was concerned about shedding” in its vaccine trials, “by inhalation or skin contact.”

These are false claims. The Pfizer vaccine does not cause viral shedding and does not lead to “menstrual disruption” and “miscarriages.” 

First, for some context on vaccine shedding. In an email to The Dispatch Fact Check Vincent Racaniello, professor of microbiology and immunology at Columbia University, explained vaccine shedding as “any of the material that is injected into you and then 'comes out' of the needle wound,” he said. “This is bound to be minimal because the injection is deep into the muscle and then a band-aid is usually put on top. With some vaccines, like oral polio vaccines, one ingests the vaccine and then it is shed in the stool.”