Walensky claims she was unaware the shots might lose effectiveness over time. Yet scientists around the world have long known that coronaviruses are very prone to mutation, and mutations are known to affect a vaccine's effectiveness Walensky has also accused the public of believing that "science is black and white" when, in fact, "science is gray." Meanwhile, anyone who has held an opinion that differs from the mainstream narrative has been censored to stifle scientific debate, and Walensky has never spoken out against this effort to prevent a "black and white" presentation of science