CDC Experts Fear Talking About Vaccine Safety Amid Threats and Firing

WASHINGTON — Medical experts at the U.S. Centers for Disease Control and Prevention are reluctant to publicly discuss vaccine safety because they fear violent threats tied to misinformation about vaccines, former top CDC officials told a Senate panel Wednesday.

“I have many that won’t speak about vaccines now and have removed their names off of papers,” Dr. Debra Houry, the recently former CDC chief medical officer, told the Senate Health, Education, Labor and Pensions Committee. “They don’t wish to present publicly anymore because they feel they were personally targeted because of misinformation.”

The exposure of those threats comes as former CDC acting director Dr. Susan Monarez testified about her firing by Health and Human Services Secretary Robert F. Kennedy Jr., a move she described as politically motivated and tied to pressure to push unscientific vaccine directives. Monarez said she fears for the safety of the CDC and its personnel as conspiracy theories about vaccines become more mainstream and can, in turn, fuel violence against health workers.

“I myself was subject to threats,” Monarez said, noting that she had urged the panel to rely on established science rather than political directives. “I am very concerned that the further promulgation of misleading information will undermine not just the safety and health of our children, but it will also exacerbate some of these tensions ― the willingness to commit harm if someone is affronted by a belief that the people like us that are trying to help them are actually not trying to help them.”

The Senate confirmed Monarez to lead the CDC in late July, and she had only been on the job for a few weeks when Kennedy abruptly fired her last month after she refused to rubber-stamp his directives for vaccines, according to testimony and public statements from Houry and others.

Houry and other top CDC officials resigned in protest following Monarez’s firing, signaling a broader rift inside the agency over leadership and the direction of vaccine policy amid a surge of misinformation online and in political circles. Kennedy has been widely cited for promoting vaccine narratives that federal scientists say lack scientific support, a stance that has roiled the agency and its stakeholders.

Houry said the political clash has rippled through the agency’s science workforce. “We’ve had people pull out of presenting at this week’s meeting of the Advisory Committee on Immunization Practices,” she said, referring to the CDC’s vaccine-advisory panel. “Even at the ACIP meeting, you’ll notice we don’t have our subject matter experts presenting anymore. It’s taken up to a leadership level because we did that to protect our staff and scientists, so that they would be disconnected and their names not associated.”

The ACIP has long served as a cornerstone for federal vaccine policy, developing evidence-based recommendations that shape immunization practices nationwide. In recent weeks, Kennedy’s leadership changes have raised questions about whether the panel’s independence and the integrity of its work can withstand political pressures.

The episode comes amid a shooting outside the CDC’s Atlanta headquarters last month, which officials said was motivated by opposition to COVID-19 vaccines. A lone attacker fired more than 180 rounds at the facility, and investigators later said the bullets damaged the building and surrounding areas, underscoring the real danger public health workers face from conspiracy theories and threats. Houry corrected a member’s recollection in the hearing, noting the total number of rounds fired was 500, with 180 hitting the building; she stressed the trauma experienced by staff who were nearby when bullets whizzed past.

The violence has intensified the sense that public health discussions on vaccine safety are being conducted under guard. Houry described staff members who would normally present data and safety analyses as opting out of public appearances to avoid becoming targets. “So that they won’t be targeted,” she added.

Monarez’s firing and the broader shakeup have layered context onto a long-running debate about how vaccine safety research is communicated to policymakers and the public. While CDC researchers emphasize that vaccines remain safe and effective based on decades of data, critics have argued that the agency has too much influence over public health messaging and has occasionally overstated risk reductions for certain vaccines. Proponents, including many in Congress and public health groups, maintain that a strong, transparent safety signal system is essential to sustaining public trust—especially as misinformation spreads fast across social media.

The underlying science that vaccines are safe and effective has remained consistent, officials emphasized. Houry noted that the body of evidence supporting vaccines continues to grow, including ongoing monitoring of adverse events and long-term studies that show vaccines prevent disease and save lives. She urged patience and adherence to rigorous review processes even as the political climate makes public discourse more volatile.

As the political drama unfolds, public health researchers say the immediate concern is safeguarding the capacity of the federal immunization program to operate with scientific independence. “Our job is to protect the health of the public, and that includes being honest about uncertainties where they exist and basing decisions on the best available evidence, not on political calculations,” Houry said.

The situation has renewed calls for strong protections for federal health workers and for robust, nonpartisan scientific oversight of vaccine safety. In the months ahead, observers will be watching whether the ACIP and CDC leaders can maintain course, preserve scientific credibility, and reassure a public increasingly anxious about vaccines.

In the meantime, public health experts say vaccine safety continue to be supported by a substantial and growing body of research, and that scientific consensus remains that vaccines are safe and effective when used as recommended. The events surrounding Monarez’s firing, the shooting outside the CDC, and the ongoing leadership shifts at the agency are likely to influence how future vaccine safety discussions are framed and communicated to policymakers and the public.

The full implications of these leadership changes are not yet clear, but the combination of threats, political interference, and high-profile public incidents has highlighted vulnerabilities in the public health system’s ability to communicate adverse events and risk without open conflict. Health officials stress that preserving the integrity of vaccine safety research is essential to maintaining public trust and ensuring continued confidence in immunization programs that protect communities across the country.