Trump praises polio vaccine as 'greatest thing,' while lawyer Aaron Siri petitions FDA to revoke US vaccine approval. Siri, affiliated with Trump's HHS pick Robert F. Kennedy Jr., seeks withdrawal of inactivated polio vaccine approval until safety trials are conducted. Kennedy, a vaccine skeptic, supports informed choice. Polio vaccination is hailed as a global public health achievement, though Siri's petition highlights lack of placebo-controlled trials, which experts deem unethical. The inactivated polio vaccine used in the US is safer than the oral version, though it doesn't stop virus transmission.