evidence: SARS-CoV-2, the virus that causes COVID-19, has spike protein on its surface and uses it to enter cells. The COVID-19 vaccines approved or authorized in the U.S. either contain spike protein or instruct a person’s cells to make spike protein. The immune system mounts a response to the spike protein, better preparing it to recognize and respond to the virus if it encounters it in the future. [...] McCullough and co-authors theorized in their article that their regimen can target the spike protein based on studies in which researchers found that nattokinase or natto extract could degrade spike proteins or pieces of them. Nattokinase is derived from natto, a food made from fermented soybeans. The studies were done in vitro, meaning they were done in lab dishes. They did not show whether nattokinase can degrade the spike protein in humans, nor even in animals. [...] Tanikawa, Takashi et al. "Degradative Effect of Nattokinase on Spike Protein of SARS-CoV-2." Molecules. 24 Aug 2023.