HHS to Require Placebo-Controlled Trials for New VaccinesHHS to Require Placebo-Controlled Trials for New Vaccines
Health Secretary Robert F. Kennedy Jr. speaks during a Cabinet meeting at the White House on April 30, 2025. Andrew Harnik/Getty Images
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HHS to Require Placebo-Controlled Trials for New Vaccines

Many vaccines licensed in the United States were tested against other vaccines, rather than a placebo, HHS noted in 2018.
Updated:

Health Secretary Robert F. Kennedy Jr. is requiring all new vaccines to be tested against placebos before being licensed, officials said on April 30.

The requirement is “a radical departure from past practices,” a spokesperson for the Department of Health and Human Services (HHS) told The Epoch Times in an email.

“Except for the COVID vaccine, none of the vaccines on the CDC’s childhood recommended schedule was tested against an inert placebo, meaning we know very little about the actual risk profiles of these products,” the HHS spokesperson said.

A placebo is a substance that “has no effect on living beings,” according to the Centers for Disease Control and Prevention. The Food and Drug Administration (FDA) defines it as an “inactive preparation.” Neither agency responded to requests for comment.

Many vaccines licensed in the United States were tested against other vaccines, rather than against a placebo, HHS acknowledged in a 2018 letter to the Informed Consent Action Network.

Federal regulators, who are part of HHS, have not approved any vaccines since Kennedy was sworn in as health secretary in February.

Prior to becoming health secretary, Kennedy chaired Children’s Health Defense, an organization that has raised concerns about virtually all vaccines. He told The Epoch Times in 2023 that vaccines “are not tested for safety against placebos in any kind of functioning trial prior to being approved.”

Some experts say that placebo-controlled trials for established vaccines, such as the measles, mumps, and rubella (MMR) shots, would not be ethical because it would deny participants in the control arm a vaccine.

“Inclusion of placebo control groups is considered unethical,” HHS said in the 2018 letter. Others say that placebo-controlled trials can be justified on an ethical basis.

Dr. David Wohl, a professor at the University of North Carolina at Chapel Hill’s Institute of Global Health and Infectious Diseases, told The Epoch Times in an email that he believes that placebo-controlled trials are not ethical for infectious diseases for which there are vaccines.

“For infections where a vaccine does not exist, a placebo can be considered; however, this may not be ideal, as vaccines commonly cause side effects like soreness at the injection site or achiness as the body responds to the vaccine as intended,” Wohl, who worked on the trial for Pfizer’s COVID-19 vaccine, said. In those circumstances, the control group could receive an existing vaccine for another disease.

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Boxes and vials of the measles, mumps, rubella (MMR) vaccine are seen at a Lubbock Public Health Department clinic in Lubbock, Texas, on March 1, 2025. Health Secretary Robert F. Kennedy Jr. announced on April 30 that all new vaccines must be tested against placebos before receiving approval. Jan Sonnenmair/Getty Images

Aaron Siri, a lawyer who represents the Informed Consent Action Network, told The Epoch Times via email that “a clinical trial without a proper control cannot properly assess safety.”

The network created a chart summarizing the trials of vaccines on the CDC’s schedule.

“What hangs in the balance of these trials is the safety of a product typically injected into millions of healthy infants and children every year,” Siri said, noting that Congress gave vaccine manufacturers immunity from liability through the 1986 National Childhood Vaccine Injury Act.

“That is an incredible moral and safety hazard.”

Delay on Vaccine

The new HHS announcement was made after regulators opted against approving Novavax’s application for a license for its COVID-19 vaccine by a recent deadline, a move that officials have since attributed to how the vaccine features an updated formulation that is different from the formulations that received emergency authorization in the past.

“Trials from four years ago conducted in people without natural immunity no longer suffice,” an HHS official told The Epoch Times in an email.

“A four-year-old trial is also not a blank check for new vaccines each year without updated clinical trial evidence, unlike the flu shot which has been tried and tested for more than 80 years.”

The FDA has for years cleared updated influenza vaccines on an annual basis. The FDA, which sits within HHS, began clearing new formulations of COVID-19 vaccines on an annual basis in 2023 in a bid to tackle waning effectiveness. Both shots have been estimated to provide protection that starts at or quickly dips below 50 percent.

FDA Commissioner Dr. Marty Makary indicated on CBS on April 29 that the agency may not clear a new round of COVID-19 vaccines ahead of the 2025–26 virus season.

“We’re taking a look,” Makary said, adding later that “there’s a void of data, and I think rather than allow that void to be filled with opinions, I'd like to see some good data.”
The FDA in 2024 cleared updated COVID-19 vaccines from Pfizer and Moderna without clinical data. The agency later granted emergency authorization to Novavax’s updated shot, despite a lack of data from human trials. The agency cited animal testing and data from human testing of prior formulations.
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Health Secretary Xavier Becerra speaks after receiving an updated COVID-19 booster and a flu shot at a local CVS Pharmacy in Washington on Sept. 20, 2023. Drew Angerer/Getty Images
Kennedy has also suggested that the COVID-19 vaccine could be taken off the CDC’s schedule, a stance backed by Makary.

Dr. Monica Gandhi, professor of medicine and associate chief of the University of San Francisco Division of HIV, Infectious Diseases, and Global Medicine, told The Epoch Times in an email that she does not think new trials are necessary for updated formulations in light of how the vaccines were tested in human trials during the COVID-19 pandemic and how updated vaccines target newer variants of the same disease.

“‘Immunobridging’ demonstrations (showing elicitation of antibody responses) should be just fine,” Gandhi said.

Building New Surveillance Systems

Kennedy, speaking in a town hall on April 28, said that “there’s no surveillance system” monitoring the safety of vaccines once they receive approval and people start receiving them.
Monitoring systems run by the CDC and FDA include the Vaccine Adverse Event Reporting System (VAERS), to which people can voluntarily report adverse events following vaccination, and the Vaccine Safety Datalink, which involves 11 health care sites reporting information from electronic records.

“CDC prioritizes high-quality vaccine safety research and identification of adverse events through public health surveillance,” the agency states on its website.

An HHS spokesperson referenced a study that found few post-vaccination adverse events are reported to VAERS.

“It’s a system that was designed to fail,” the spokesperson said.

The spokesperson also described the Vaccine Safety Datalink as “virtually unusable for serious research” and said that both systems “have become templates of regulatory malpractice.”

“[HHS is] now building surveillance systems that will accurately measure vaccine risks as well as benefits—because real science demands both transparency and accountability,” the spokesperson said.

Wohl noted that adverse events reported to VAERS spurred investigations into COVID-19 vaccines that resulted in warnings of possible side effects such as heart inflammation being added to labels for the vaccines. He said that one way to improve vaccine safety monitoring would be to expand the Vaccine Safety Datalink.
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A sign in a pharmacy advertises the COVID-19 vaccine as the nation marks the fifth anniversary of the COVID-19 pandemic in New York City on March 11, 2025. Spencer Platt/Getty Images
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