Thomas J. Bollyky is the inaugural Bloomberg Chair in Global Health at the Council on Foreign Relations, where he directs the global health program.
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Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. faced intense scrutiny during a Senate Finance Committee hearing yesterday, which was ostensibly convened to discuss President Donald Trump’s 2026 health care agenda. However, the hearing quickly turned to concerns Republican and Democratic senators had with Kennedy’s vaccine policies and the recent turmoil at the Centers for Disease Control and Prevention (CDC).
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The abrupt firing of Susan Monarez as the CDC director last week, just a month after her confirmation, served as one of the focuses of the hearing, leading to allegations that politicization of HHS efforts had undermined scientific consensus. Concerns at the hearing also encompassed Kennedy’s broader overhaul of vaccine policy, which includes his decision to replace all members on the CDC’s Advisory Committee on Immunization Practices (ACIP).
Critics argue that Kennedy’s tenure has undermined trust in the CDC and its scientific basis, eroding its global standing as a public health leader, and risked public health by fostering confusion and misinformation. Kennedy has rejected these characterizations and maintained that HHS requires an overhaul.
To better understand the fallout and how it could affect health initiatives in the United States and abroad, the Council on Foreign Relations turned to Thomas Bollyky, the inaugural Bloomberg Chair in Global Health, for his assessment.
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How serious are the latest developments involving CDC leadership and U.S. vaccine policy?
There is no question that the events of the last week have put the health and lives of Americans at risk.
The reasons begin with the loss of CDC leadership, organizational capacity, and decades of institutional memory and expertise. The decision of the U.S. Health and Human Services Secretary Robert F. Kennedy Jr. to fire Susan Monarez as CDC director, and the subsequent resignation of many respected, experienced senior officials, is just extraordinarily harmful. The departed officials included the chief medical officer and the leaders of many of the most critical functions at the agency, including its centers for immunization and respiratory diseases; emerging and zoonotic infectious diseases; and public health data, surveillance, and technology. The agency was already reeling from mass layoffs, the elimination of critical programs, and low morale after a shooting at the CDC main campus perpetrated by an individual citing conspiracy theories on COVID-19 vaccines, similar to those espoused by the secretary and his allies. Now this.
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These latest developments also undermine the stated goals of the Trump administration: to bolster trust in the CDC and in the evidence base for U.S. vaccination policy amid the partisanship and polarization that arose around public health after the COVID-19 pandemic.
The dismissal of Monarez—a respected microbiologist and career civil servant who Kennedy himself recommended, President Trump nominated, and a Republican-majority Senate confirmed just a month ago—reportedly stemmed from her refusal to commit to accepting, without alteration, changes to the childhood vaccine schedule based on the recommendations of ACIP. U.S. law charges the CDC director with reviewing ACIP recommendations and deciding whether to adopt them as official federal government recommendations. Earlier this year, Kennedy removed all seventeen ACIP members, replacing them with appointees that included individuals who had promoted vaccine conspiracy theories and unproven COVID-19 treatments.
How could it affect public health efforts?
The fallout of these actions has been the splintering of the U.S. public health system along political lines, with some states loosening vaccine requirements and others seeking to break away from the Trump administration’s guidelines. California, Oregon, and Washington have announced a coalition to issue vaccine recommendations, citing Kennedy’s “destruction” of the CDC. Hours later, Florida announced that it would become the first state in the nation to end all school vaccine mandates. Colorado and New Mexico issued orders allowing pharmacies to administer COVID-19 vaccines without prescriptions to circumvent recent federal recommendations.
The timing for all this could not be worse, as it spurs public confusion over vaccines when students go back to school and flu and respiratory illness season starts. Without consensus over federal recommendations, insurance companies may not cover some vaccines. This could make them expensive for most Americans—and prohibitively so for many more. The United States is already in the midst of the largest measles outbreak in a generation, which continues to grow despite the secretary declaring it over. It is now up to 1,431 cases and three deaths, the most since the country reached elimination status in 2000.
How have the cuts, political pressures, and public spats affected the CDC’s global standing?
For eighty years, the CDC has served as a crucial link between domestic and global health. While the agency was created to address domestic needs, it has had a central role in many multilateral efforts, including the eradication of smallpox and the West African Ebola epidemic response. It has also been the world’s leader in public health research and training, pandemic preparedness and response, and standard setting.
The Trump administration’s defunding of many of the agency’s global functions dismantles partnerships and lifelines that have been in place for decades. Earlier this year, the CDC was restricted from engaging in technical discussions and data sharing at the World Health Organization, the UN health body from which the Trump administration has also withdrawn. The collapse of the agency’s global role is part of a larger U.S. withdrawal on global vaccination policy, which culminated earlier this year with Secretary Kennedy’s announcement that under his leadership, Washington would stop funding Gavi, the global vaccine alliance that provides routine immunizations to 70 million children each year.
Have the changes and new recommendations at HHS, including the restriction of vaccine research funding and access, undermined vaccine trust outside of the United States?
It will. U.S. Food and Drug Administration decisions on vaccine safety have in the past influenced other nations’ decision-making on many vaccines, from rotavirus to COVID-19. While other countries and other governments have so far increased their support for Gavi in response to Secretary Kennedy’s claims that the global alliance is weak on vaccine safety, resurfacing debunked claims that evidence of links to autism have been suppressed will be corrosive to public confidence globally.
After the onset of the COVID-19 pandemic, the United States, which has long been a leader on global vaccine policy, has become a source of global vaccine misinformation—largely through social media. Peer-reviewed studies of hundreds of millions of social media posts during the COVID-19 pandemic found that U.S.-based accounts disproportionately were the hubs in global misinformation networks. The most prominent account belonged to Robert F. Kennedy Jr., who accounted for more than 13 percent of these retweets of “low-credibility vaccine content.” That online misinformation has lowered vaccine confidence globally.
Over the last few months, the vaccine misinformation that could only be found online is now creeping into official U.S. policy sources and vaccine recommendations—and it will begin to reverberate globally, too.
Both Democrats and Republicans raised concerns about the changes Kennedy has made. What recommendations would you give to policymakers to reestablish confidence in U.S. public health standards?
Vaccine policy generates public confidence and trust when it is grounded in the best available science. It must be developed in consultation with career government subject matter experts and according to the procedures outlined in law. It then must be communicated openly and honestly, without political interference.
It is critical that we reestablish that standard at HHS and CDC, and Congress and the public must insist upon it. What we heard at the Senate hearing with the secretary this week was bipartisan concern, including from Republican senators who are physicians, that the secretary is falling well short of this standard on U.S. vaccine policy.
That concern needs to start evolving into real accountability and a demand for change. The lives and safety of Americans, and vulnerable populations around the rest of the world, depend on it.
This work represents the views and opinions solely of the authors. The Council on Foreign Relations is an independent, nonpartisan membership organization, think tank, and publisher, and takes no institutional positions on matters of policy.