In what has become a pattern of spreading vaccine misinformation, the Florida health department is telling older Floridians and others at highest risk from covid-19 to avoid most booster shots, saying they are potentially dangerous.

Clinicians and scientists denounced the message as politically fueled scaremongering that also weakens efforts to protect against diseases like measles and whooping cough.

A prominent Florida doctor expressed dismay that medical leaders in the state, leery of angering Gov. Ron DeSantis, have been slow to counter anti-vaccine messages from Surgeon General Joseph Ladapo, including the latest covid bulletin. Ladapo is a DeSantis appointee and the top official at the state health department.

The bulletin makes a number of false or unproven claims about the efficacy and safety of mRNA-based covid vaccines by Pfizer and Moderna, including that they could threaten “the integrity of the human genome.” Florida’s guidance generally regurgitates ideas from anti-vaccine websites, said John Moore, a professor of microbiology at Weill Cornell Medicine.

Ladapo did not respond to a request for comment. DeSantis referred questions to the health department, which said the surgeon general’s guidance and citations “speak for themselves” and pointed to a post he made on the social platform X accusing the Centers for Disease Control and Prevention and FDA of “gaslighting Americans.”

DeSantis has styled himself and his administration as a bulwark against vaccine mandates, lockdowns, and other restrictive public health protections adopted during the pandemic to curb infections and save lives. Covid vaccination has become a partisan issue, with surveys by KFF, the health information nonprofit that includes KFF Health News, finding that Republicans have far less confidence in the safety and efficacy of the shots than Democrats.

But vaccine historians consulted for this article could not recall any previous state health leader urging residents to shun an FDA-approved and CDC-recommended vaccination. “It’s unprecedented,” said Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia.

Florida medical leaders should speak out more forcefully against Ladapo’s attacks on public health, said Jeffrey Goldhagen, a pediatrician and professor at the University of Florida College of Medicine in Jacksonville. Ladapo urged people under 65 to avoid covid shots last year and has rejected public health protocols for fighting measles outbreaks.

“What you see is a pattern of fear and neglect of professional responsibilities across the state, in part because of the fear of this governor and the vindictiveness of this governor,” said Goldhagen, a former health department director in Jacksonville.

He specifically criticized the Florida Medical Association, a trade group for physicians, noting that Ladapo is a nonvoting member of the group’s board of governors. The association did not respond to emails requesting comment.

The Florida Health Care Association, whose members run more than 600 long-term care facilities, declined to comment on Ladapo’s bulletin. One nursing home chain, LeadingAge Southeast, said it was aware of both federal and state recommendations on covid boosters and encouraged providers to “engage with their residents, families, and healthcare professionals to make informed decisions.”

A spokesperson for the U.S. Food and Drug Administration, Cherie Duvall-Jones, said the agency “strongly disagrees with the State Surgeon General of Florida’s characterization of the safety and effectiveness of the updated mRNA COVID-19 vaccines.” The vaccines met the FDA’s “rigorous, scientific standards,” she said, and she urged people to get boosters since the population’s covid immunity has waned.

Among its incorrect claims, the Florida bulletin says the new mRNA boosters wrongly target a viral variant, omicron, that is no longer circulating widely. This is false, since all major variants of covid in the past two years evolved from omicron and subsequent mutations.

“You start off with that and then you go into head-exploding-emoji territory,” Moore said. “It’s a litany of lies out of the anti-vaxxer playbook.”

Other claims in Ladapo’s bulletin include:

• Covid boosters don’t undergo clinical trials. It’s true that covid booster shots, whose mRNA sequences are changed slightly from previous shots, aren’t tested in large trials. Neither are annual influenza vaccines. By the time such tests would be completed, flu season would be over. But the original mRNA shots underwent clinical trials, and as with flu shots, “a lot of evidence has been collected in support of the ongoing use of the vaccines,” said Natalie Dean, a biostatistician at Emory University’s Rollins School of Public Health.
• The shots pose a risk of infections, autoimmune disease, and other conditions. “I don’t know where these claims come from, but they aren’t accepted by the general medical community,” said William Schaffner, a Vanderbilt University School of Medicine infectious disease specialist. Serious side effects do occur, rarely, as with any medication. U.S. authorities were among the first to detect rare occurrences of myocarditis, an inflammation of the heart tissue, in young adults who got the covid vaccine. Most patients recovered quickly. Myocarditis is more commonly caused by covid infection itself.
• The shots could cause elevated levels of spike protein and foreign genetic material in the blood. These concerns, which circulate on social media, have been disproved or have not panned out. For example, the billionths-of-a-gram quantities of bacterial DNA alleged to be contaminating covid shots are dwarfed by our other exposures, Offit said. “You encounter foreign DNA all the time, assuming you live on the planet and eat anything made from animals or vegetables,” he said. “I don’t know Dr. Ladapo, but I assume he does.”
• Americans face “unknown risk” from too many booster shots. Scientists look at the possibility of “overvaccination” every time they study boosters. So far, no safety risks have been associated with multiple immunizations, Schaffner said.
• Floridians should get exercise and eat vegetables and “healthy fats.” “These things will benefit your general health, but none of them will prevent covid,” Schaffner said.

The bulletin urges all Floridians, including older residents, to avoid mRNA vaccines and find alternatives. But it comes off as “not in good faith” because it doesn’t specifically mention the only non-mRNA vaccine available, from Novavax, Dean said.

Several critics of Ladapo’s bulletin said it read like a tryout for a job in a Trump administration advised by longtime anti-vaccine activist Robert F. Kennedy Jr., who has said Trump wants him to help vet senior health officials. Trump has said children receive too many vaccines and suggested that vaccines cause autism, a myth debunked by years of scientific research.

Ironically, although his administration oversaw the triumphantly rapid creation of the first covid vaccines, Trump declined to receive his shots in public, as presidents have done during past epidemics.

Ladapo’s vaccine statement “aligns with Project 2025,” Offit said, referring to the conservative Heritage Foundation policy blueprint. While the plan’s authors include officials from Trump’s first term, he has said it doesn’t reflect his views.

The document calls the CDC “perhaps the most incompetent and arrogant agency in the federal government.”

Organized resistance to vaccines has existed as long as vaccination itself. Within six months of the release of the mRNA vaccines in December 2020, about 70% of American adults were vaccinated. Those who refused put themselves at greater risk of hospitalization or death if they contracted covid, studies have shown.

Cheryl Holder, an internist who practices in Miami, said Ladapo’s statements had dampened interest in vaccination overall. People who are blasé about covid “also don’t want to take the tetanus vaccine, and they don’t want to take the pneumococcal vaccine, or the flu vaccine,” she said.

“We’re in the disinformation age,” Offit said. “It’s certainly a lucrative business, more lucrative than the information business. But what really bothers me is when you have people who are credentialed stand up and say these ridiculous things.”

Ladapo, he noted, has medical and doctoral degrees from Harvard.

Healthbeat is a nonprofit newsroom covering public health published by Civic News Company and KFF Health News. Sign up for its newsletters here.

By Arthur Allen and Daniel Chang and Sam Whitehead
Kaiser Health News is a nonprofit news service covering health issues. It is an editorially independent program of the Kaiser Family Foundation, which is not affiliated with Kaiser Permanente.