Vaccine Approvals May Require Placebo-Controlled Clinical Trials

According to various media reports today, the U.S. government is modifying the method for authorizing or approving vaccines for human use.

“All new vaccines will undergo safety testing in placebo-controlled trials prior to licensure,” a U.S. HHS spokesperson told The Washington Post in response to an inquiry about HHS Secretary Robert F. Kennedy Jr.’s comments on the measles vaccine and general vaccine policy.

HHS did not clarify which vaccines this new policy would apply to, according to the Post on April 30, 2025.

The government's Clinical Trials website defines placebo-controlled trials as studies using an inactive substance or treatment that appears the same as, and is administered in the same manner as, an active drug or intervention being studied. The placebo comparator arm of the study is a group of participants who receive a placebo during a clinical trial.