Login
In a recent Substack post, longtime vaccine advocate Dr. Paul Offit offered up “three simple rules” for “How to Be an Effective Anti-Vaccine Activist” — but according to Children’s Health Defense (CHD) Senior Research Scientist Karl Jablonowski, Offit may as well have been describing the pro-vaccine playbook.
Jablonowski accused Offit of mischaracterizing the science and the broader debate.
“This is certainly a playbook,” Jablonowski said on “Good Morning, CHD.” “I have been lied to about vaccine safety, and I have been lied to about vaccine efficacy. And certainly important studies have been suppressed that address vaccine safety and efficacy.”
Offit, a longtime vaccine proponent and critic of U.S. Health Secretary Robert F. Kennedy Jr., wrote, “Thanks to RFK Jr., during the past year, American children have suffered and died from preventable diseases like measles, whooping cough, and influenza at rates greater than have been seen in decades.”
He told readers: “If you want to convince people not to vaccinate their children, you need to follow three simple rules.”
Jablonowski addressed each of Offit’s three claims.
‘Rule #1: Lie about vaccine safety’
Offit argued that Kennedy has “falsely claimed” vaccines are linked to serious harms — including that COVID-19 vaccines were the deadliest ever made and that the hepatitis B (Hep B) vaccine causes autism.
In response, Jablonowski pointed to concerns he said are inherent to vaccine design, particularly for live-virus vaccines. He said the measles vaccine and similar shots originate from wild-type viruses that are repeatedly cultured, creating opportunities for mutation.
“So it is certainly possible that any live virus vaccine can inadvertently infect the person with a dangerous virus,” he said.
Turning to COVID-19 vaccines, Jablonowski said that widespread global use changes how risk is measured. “It may not be the most lethal per dose, but it certainly is taking top prize for total deaths,” he said.
As for Hep B vaccines, Jablonowski said aluminum adjuvants remain central to the scientific debate. He cited research he co-authored that shows a causal relationship between aluminum exposure and “the manifestations of autism.”
‘Rule #2: Lie about vaccine efficacy’
Offit pointed to statements by Kennedy suggesting declines in diseases like measles were driven more by sanitation and hygiene than vaccination. He cited pertussis and measles data to argue that Kennedy is wrong.
Jablonowski rejected that framing, saying it overlooks the broader context in which vaccines were introduced. He called the argument “kind of a funny one,” noting that vaccines arrived alongside major public health advances.
“Vaccines are appearing on the coattails of some major modern innovations to hygiene and sanitation and … modern medicine,” he said.
The issue also surfaced in recent congressional hearings, where Kennedy cited a study in Pediatrics.
According to that study, “Nearly 90% of the decline in infectious disease mortality among US children occurred before 1940, when few antibiotics or vaccines were available.” The study noted that the pertussis vaccine has been available since the late 1920s.
The study’s authors attributed the decline in mortality to improved socioeconomic conditions and public health measures, including water treatment, food safety, waste disposal and hygiene education.
‘Rule #3: Actively suppress studies showing that vaccines are safe and effective’
According to Offit, federal health officials under Kennedy have suppressed favorable vaccine research.
He cited a respiratory syncytial virus (RSV) study published in May 2025 by the Centers for Disease Control and Prevention (CDC). The study showed that giving RSV vaccines to pregnant women, or administering the monoclonal antibody nirsevimab to infants, reduced RSV hospitalization rates for infants 0-7 months old.
Offit said the CDC typically produces press materials with “talking points and other details” for high-impact studies, but that “RFK Jr. muzzled the CDC media outreach” for the RSV study.
Jablonowski rejected that claim. “The CDC apparently didn’t do all of the PR that … Offit wanted,” he said. Jablonowski also challenged the study’s methodology, describing it as “odd” because the researchers compared RSV data from 2018-2020 — when RSV vaccines and monoclonal antibodies were not widely available — with data from 2024-2025.
“To even make that comparison, you have to believe that the ecosystem is identical,” Jablonowski said. He pointed out that the COVID-19 pandemic occurred “right smack in the middle” of that time frame. “That really changed the landscape for infectious diseases around the world,” he said.
Jablonowski urged caution regarding “RSV and our interventions against it.”
He cited research showing some babies who received the RSV shot nirsevimab, marketed as Beyfortus, developed a shot-resistant strain of the illness. “This appears to be the genesis of resistance right there,” Jablonowski said.
Offit also wrote that “RFK Jr. took his suppression of studies one step further” by censoring a COVID-19 vaccine efficacy report. He said Interim CDC Director Jay Bhattacharya delayed publication over concerns about methodology.
Jablonowski focused on that methodology, criticizing the “test-negative design” used in the study. He said the approach assumes vaccinated and unvaccinated groups are effectively identical.
For the test to be valid, the two groups would need identical immune systems, identical social behavior and identical healthcare-seeking behavior, he said.
But meeting those conditions is unrealistic, he said. “Who is still getting boosted for COVID-19 in the 2025-26 season?” he asked, suggesting that significant behavioral and health differences between the groups could skew results.
“The idea that the two groups … are identical … is absolutely ridiculous,” he said, “I want my tax dollars to stop funding test-negative designs. They are horribly misleading.”
He pointed to conflicting findings in other studies as further evidence that the “test-negative design” is flawed.
The Defender is 100% reader-supported. No corporate sponsors. No paywalls. Our writers and editors rely on you to fund stories like this that mainstream media won’t write. 
This article was funded by critical thinkers like you.
For example, a CDC flu vaccine efficacy study using the test-negative design reported a tie for the second-highest efficacy on record during the 2024-2025 season. However, a Cleveland Clinic study from that same season found that people who got the flu vaccine were more likely to get the flu.
“Those two are at complete odds with each other,” Jablonowski said. “The test-negative design is not the valid one in this case.”
Jablonowski also argued that Offit’s perspective reflects long-standing ties to the vaccine establishment.
He noted Offit co-authored “Plotkin’s Vaccines” with three others, including Dr. Stanley Plotkin, often referred to as the “godfather of vaccines.” Offit also wrote “Deadly Choices: How the Anti-Vaccine Movement Threatens Us All.”
Offit is also co-inventor of the RotaTeq vaccine, later acquired by Merck in a deal Jablonowski said included a minimum $6 million payout.
Watch Jablonowski counter Offit’s vaccine claims here:
Related articles in The Defender
- RFK Jr. Clashes With Lawmakers Over Measles, COVID and Chronic Disease
- RFK Jr. Taps 8 New ACIP Members, Offit Concedes Most ‘Seem Reasonable’
- ‘Deeply Concerning’: This Year’s Flu Shots Led to 27% Higher Risk of Flu
- Offit Lied to CNN About ACIP Meeting, Hepatitis B Data. CNN Didn’t Fact-Check Him
- ‘Worrying’: RSV Shot Linked to Drug-Resistant Strains in Infants
