Kennedy Jr. vowed Thursday evening that his push to discover what causes autism will be transparent and quick. “We’re going to be very transparent in how we design the studies,” he told Fox News’s Sean Hannity in an interview.

Kennedy, Hotez says, made a “false statement” in claiming that the scientific community denies that there are any environmental factors at play. “I’ve said to RFK Jr. that there could be an environmental component, but not vaccines, because autism occurs in fetal brain development well before kids ever see vaccines.”