Sen. Bernie Sanders, I-Vt., shares his thoughts on HHS Secretary RFK Jr. sidestepping vaccine questions during back-to-back congressional hearings with Chris Hayes on All In With Chris Hayes. "When you have the head of HHS unable to answer a question about whether or not he supports vaccines for measles, everybody in this country should be deeply concerned," Sanders said. For more context and news coverage of the most important stories of our day click here: https://www.msnbc.com/ » Subscribe