US Health Secretary Robert F Kennedy Jr is driving an agenda based on ideology not science, and tried to reduce the Centers for Disease Control and Prevention (CDC) to a rubber stamp, according to the two former top officials.

Former CDC director Dr Susan Monarez and Dr Debra Houry, former Chief Medical Officer and deputy director for Program and Science, provided damning testimony of Kennedy’s interference at a Senate health committee hearing on Wednesday, called after the mass resignation of the CDC’s top leaders late last month.

Senator Bill Cassidy, instrumental in confirming Kennedy’s appointment after being assured that he would not change the country’s vaccine schedule, called the hearing. 

Earlier, Kennedy told the Senate finance committee that he had removed Monarez – who was the Republican Party’s representative and appointed by the Senate health committee – after she admitted to being “untrustworthy”.

But Monarez told the Senate health committee that Kennedy informed her on 19 August that she “required prior approval from [her] political staff for CDC policy and personnel decisions”.

Six days later, Kennedy “demanded two things of me that were inconsistent with my oath of office and the ethics required of a public official”, she added. “He directed me to commit in advance to approving every Advisory Committee on Immunization Practices (ACIP) recommendation regardless of the scientific evidence. He also directed me to dismiss career officials responsible for vaccine policy, without cause.

“He said if I was unwilling to do both, I should resign. I responded that I could not preapprove recommendations without reviewing the evidence, and I had no basis to fire scientific experts.”

Earlier, Kennedy sacked all 17 ACIP members and replaced them with eight people – including at least half of whom are vaccine sceptics. This week, Kennedy appointed a further five ACIP members, four of whom have expressed doubts about vaccines’ efficacy, according to The Guardian.

Kennedy was one of the foremost proponents of anti-vaccine misinformation during the COVID-19 pandemic, and the organisation he founded, Children’s Health Defense, has received hundreds of thousands in donations to litigate against vaccines.

Interference in vaccine decisions

Houry’s testimony detailed several examples of Kennedy’s interference in scientific decisions that threaten the health of Americans. 

These include replacing the ACIP with “known critics of vaccines” who operate with “decreased transparency” and “a willful refusal to follow established scientific and decision-making procedures”, said Houry, a career bureaucrat who has served at the CDC under six different administrations, including the first Trump administration.

CDC staff were asked at the “last minute” to summarise evidence about the risk of thimerosal, an additive in approximately 4% of flu vaccines, for the June ACIP meeting. 

“This thimerosal evidence review included a summary of rigorous studies and was pulled from existing information on CDC and FDA websites about its safety and lack of an association with autism,” said Houry.

But Kennedy rejected the document “while allowing an unvetted presentation on thimerosal, containing scientific assertions that were not assessed for data quality and bias”. 

“Science must be allowed to stand or fall on its merits, not on whether a scientific conclusion fits one individual’s ideological narrative,” declared Houry, who earlier stressed that US life expectancy had almost doubled in the past 150 years due to vaccines.

No flu vaccine campaign, measles vaccine undermined

The CDC has not been permitted to restart flu vaccine campaigns for the upcoming season, despite 270 influenza-associated paediatric deaths during the 2024-2025 season – the highest number of paediatric deaths ever recorded in a non-pandemic year since reporting started in 2004, Houry reported. 

Around 90% of the children who died were not fully vaccinated.

Despite the highest measles cases in the US in 30 years, Kennedy has “sowed doubt” about the measles vaccine by claiming that it “contained foetal parts”, while questioning its effectiveness and length of protection, while “promoting vitamins and unproven treatments such as inhaled steroids”, said Houry. 

“These dangerous statements can lead to adverse events like the one during an outbreak in Texas, where a hospital reported cases of Vitamin A toxicity in children,” she added.

Interference ‘beyond vaccines’

Houry detailed interference “beyond vaccines”, cutting staff “who work to decrease use of tobacco, prevent the transmission of HIV, improve oral health, and screen newborns for early detection of treatable health conditions, and many more.

Houry said the CDC’s reduced capacity put the US “at risk for threats like Ebola, Marburg, and other viral haemorrhagic fevers”, and “we won’t know which flu or COVID strain is emerging globally and when it’s coming or how bad it will be”. 

This was the result of a 60% decrease in flu submission samples and a 70% decrease in COVID submission samples, meaning “we do not have good visibility into these threats any more”, she said.

Kennedy’s plan to move the CDC’s non-communicable programs to the Administration for a Healthy America “will result in siloed, fragmented approaches to outbreaks and health threats”, said Houry, adding that non-infectious and infectious diseases are connected.

Two more paediatric vaccines may be removed

She also described a situation of “science censored, processes politicized, and transparency curtailed”, while Kennedy conveyed major decisions unilaterally via social media.

“One example: the Secretary altered CDC’s COVID vaccine guidance through a social media post without consultation, data, or process. I first learned of this vaccine policy change, not from dialogue with the Secretary’s office, but rather from an X social media post,” said Houry.

“Due to the secretary’s actions, our nation is on track to see drastic increases in preventable diseases and declines in health,” said Houry.

The ACIP meets on Thursday and Friday to review and vote on two paediatric vaccines for the hepatitis B vaccine and the measles, mumps, rubella, and varicella (MMRV). 

Monarez told the Senate that, based on her observations of ACIP, “there is real risk that recommendations could be made restricting access to vaccines for children and others in need without rigorous scientific review”.

“The stakes are not theoretical. We have already seen the largest measles outbreak in more than 30 years, which claimed the lives of two children. If vaccine protections are weakened, preventable diseases will return,” she asserted.

“I was fired for holding the line on scientific integrity. But that line does not disappear with me. It now runs through every parent deciding whether to vaccinate a child, every physician counselling a patient, and every American who demands accountability.”

Image Credits: HHS.