Fact File: HPV vaccine safe and effective despite RFK Jr. claims, experts say

A resurfaced video shows Robert F. Kennedy Jr., now U.S. health secretary, claiming children who receive the HPV vaccine Gardasil are more likely to die from the vaccine than from cervical cancer. He also says the vaccine’s data is unreliable because it was not tested against a placebo. But experts say Kennedy’s claims are false, and that the evidence supports Gardasil as safe and effective against the prevention of HPV infections that may lead to cancer. 

THE CLAIM

A video of Kennedy talking about the human papillomavirus vaccine has resurfaced online. 

In an interview clip posted multiple times on the X platform, Kennedy calls Gardasil the “single worst mass vaccine that we’ve ever seen.” He then claims the death rate in Gardasil’s clinic trials were 37 times higher than the death rate for cervical cancer, and that the vaccine’s data is unreliable because it was not tested against a “true” placebo.

“Children who take that vaccine, the Gardasil vaccine, are more likely to die from the vaccine than they are from cervical cancer,” Kennedy says.

Text that appears on screen reads “Children’s Health Defense,” referring to the name of the anti-vaccine advocacy group that Kennedy chaired between 2015 and 2023. President Donald Trump appointed him as secretary of health and human services in 2025. 

While the origin of the interview clip is unclear, Kennedy made the same comments in video remarks shared by Children’s Health Defense in 2019.

THE FACTS

Gardasil is the brand name for a vaccine that provides protection against human papillomavirus infection. Approved for use in Canada since 2019, the current version of the vaccine protects against nine types of the virus and is typically given to people between the age of nine and 26. 

Dr. Deborah Money, professor and head of the department of obstetrics and gynecology at the University of British Columbia, says the Gardasil vaccine is widely regarded as safe and effective.

Besides cervical cancer, the vaccine also prevents anal, penile, vulval and vaginal cancer, she said in an interview last week. “One, it’s safe, and two, it works really well to prevent HPV-associated cancers,” Money said. 

Reviews of safety data from the World Health Organization’s global advisory committee on vaccine safety between 2007 and 2017 found no safety concerns from either the drug’s clinical trials or surveillance after its approval and licensing.

All vaccines have some risks. Health Canada notes common adverse events associated with HPV vaccine affect between one and 10 per cent of recipients. The most common side-effects include swelling and redness at the injection site and nausea. A serious adverse event such as anaphylaxis is described as “exceedingly rare.”

Stephana Julia Moss, an epidemiologist, assistant professor at Dalhousie University and research chair at the Canadian Center for Vaccinology, said Kennedy’s claim about the death rate in Gardasil’s clinical trials being 37 times higher than the death rate for cervical cancer is an unfair comparison because it treats deaths that occurred among people in the vaccine’s clinical trials as if they were caused by the vaccine. 

“Those are fundamentally different things. In a clinical trial, we record serious events and deaths, whether or not they have anything to do with any of the interventions,” she said in an interview.

Gardasil’s package insert notes 40 deaths occurred across its clinical studies. But none of the deaths were found to be associated with the vaccine.

Among females aged nine to 45 and males aged nine to 26 who took part in clinical trials, the most common cause of death was motor vehicle accidents followed by drug overdoses or suicide, the insert says. The deaths represented less than 0.1 per cent of both the vaccine and control groups.

“The events reported were consistent with events expected in healthy adolescent and adult populations,” the package insert notes.

The National Cancer Institute in the United States shows a death rate of 2.1 per 100,000 women from cervical cancer annually as of 2024. 

If Kennedy’s claim were true, it would mean that out of the Gardasil trial’s population of roughly 29,000 participants, 22 people would have died from the vaccine, when in fact no deaths were linked to the vaccine.

Data from the vaccine adverse event reporting system from the U.S. Centers for Disease Control reviewed by researchers between 2014 and 2017 found 97 per cent of reports submitted following HPV vaccination were classified as non-serious, while about three per cent were considered serious. “The analysis did not detect any new or unexpected safety concerns,” the CDC noted.

Kennedy also claims the vaccine was never tested against “a true placebo, an inert placebo.”

In the early stages of Gardasil’s safety trials, Money said researchers used an aluminum-based adjuvant in the placebo groups — people who did not receive the vaccine — and the adjuvant plus the vaccine in the active group. They later switched to just saline in the placebo group, she added.

Adjuvants are vaccine ingredients that can create a stronger immune response. Their use is “standard methodology in vaccine studies,” Money said.

Moss said using the adjuvant as a placebo would have helped keep the study blind — meaning neither the researchers nor participants knew who was receiving the vaccine or placebo until the end of the study. 

“The control group is just simply more likely to have similar local reactions from the injection. And then sometimes, depending on the study question, it can also help to distinguish effects of the vaccine antigens from effects associated with other components in the vaccine itself,” she said.

But a placebo is not always required, or even ethical, in vaccine studies. For clinical trials of the current version of Gardasil, known as Gardasil-9, it was compared to the prior version of the vaccine.

Kennedy has a history of sharing false and misleading health information, including about the HPV and other vaccines. He was the subject of a previous Canadian Press Fact Check for misleading information related to Canada’s medical assistance in dying law. 

Kennedy, who is also a lawyer, was involved in litigation against Merck, the company that makes the Gardasil vaccine. 

This report by The Canadian Press was first published Oct. 6, 2026.