The claim that the COVID-19 Vaccine causes breast cancer is false and dangerous to spread. After fact checking I found an article on the American Cancer Society website discussing the vaccine, and the article describes that “People with cancer (or with a history of cancer) can get the COVID-19 vaccine safely. However, the vaccine might be less effective in some people with cancer.” The article goes on to describe that the effectiveness of the vaccine is very dependent on the individual situation of each person, and generally the vaccine is still effective. This article emphasizes that people with cancer should still get the vaccine, and that there are no instances of the vaccine causing cancer.
https://www.cancer.org/cancer/managing-cancer/coronavirus-covid-19-and-cancer/covid-19-vaccines-in-people-with-cancer.html
On the website Breastcancer.org there is an article about the vaccine, and this article explicitly states that “There’s no link between the COVID vaccines and breast cancer risk or developing breast cancer.” and that they recommend everyone follows the CDC guidelines and gets the vaccine.
https://www.breastcancer.org/managing-life/staying-well-during-covid-19/vaccine-facts
It becomes clear this claim is false and there is not evidence supporting a link between getting the COVID-19 Vaccine and breast cancer. It is extremely harmful to spread this claim because it could discourage people from getting the vaccine, therefore making them more susceptible to COVID-19.