It's time now for Ask An Expert. Every weekday at 9:20 AM on KCBS we're giving you direct access to top experts in various fields.

Health and Human Services Secretary Robert F. Kennedy is working to change the way we test vaccines in a move he says will increase transparency and make them safer. But some health experts are raising concern, saying this could make it harder to access vaccines and undermine the public's trust in already-tested medicine.

To answer those questions and more, KCBS Radio news anchor Eric Thomas spoke with William Schaffner, professor of preventive medicine and health policy at Vanderbilt University Medical Center.