Claim: No Current Vaccines (Except COVID) Were Safety Tested Against Placebo Before Approval

Verdict: False and misleading

"There are placebo-controlled trials, senator [...], under the current vaccine schedule, none of the vaccines – with the exception of COVID – have ever experienced a safety trial, pre-licensure, that involves an inert placebo. None of them."

"They do have efficacy tests against placebo, but they don't have safety testing"

RFK Jr., September 2025

WATCH: RFK Jr. clarifies stance on placebo trialsAmid RFK Jr.’s behind-the-scenes push to link vaccines to various illnesses, attention is turning back to his previous claims about placebo-testing vaccines. He made this argument at length in a 2023 book, Vax-Unvax: Let the Science Speak, and had to clarify his views to a Senate subcommittee last year.

While he said he didn’t want to re-test all vaccines against placebo, he did claim that only the COVID vaccine was safety tested against placebo before being approved. But is he right?

Why We Don’t Placebo-Test Most Vaccines?

We don’t usually conduct placebo controlled testing of most vaccines because that would mean exposing people to risk by denying effective treatment. Vaccines are generally tested against the current best care, which likely means an older vaccine. But in cases where vaccines are new and there is no existing treatment, tests are placebo-controlled.

The Polio Vaccine Trial

The most famous example of a controlled trial for a vaccine comes from the 1954 test of Jonas Salk’s polio vaccine. Although it did have methodological problems, 650,000 children were randomized to receive either the polio vaccine or a placebo. Not only did the vaccine work, safety monitoring found that only 0.4% of vaccinated children had minor reactions, and this was about 100 times the rate of serious reactions.

Other Placebo-Controlled Vaccine Safety Studies

There are many other examples.

In January 2006, around 68,000 infants were randomized to receive either the rotavirus vaccine or an inert placebo. Not only was the vaccine effective, risks were similar to placebo. The vaccine was approved later that year.

Between 2002 and 2003, the HPV vaccine was tested in over 12,000 women, who received either the vaccine or the placebo at random. The study was published after the vaccine’s 2006 approval, but was conducted before. Again, the study found the vaccine to be both safe and effective.

Researchers have compiled a spreadsheet of such studies, which is linked in the comments.