With the recent pick of Robert F. Kennedy Jr. to lead the Department of Health and Human Services, the environmental attorney's views on vaccines have been thrust back into the spotlight. Kennedy has been a prominent vaccine skeptic,

Kennedy has been criticized for making false medical claims. He has also vowed to purge the U.S. Food and Drug Administration.

The nearly $2 trillion agency administers health-insurance programs for millions of Americans, approves medications and oversees vaccine safety.