At a Sept. 4, 2025, listening to earlier than the Senate Finance Committee, Well being and Human Providers Secretary Robert F. Kennedy Jr. confronted heated questions from quite a few senators about his vaccine insurance policies, together with his stance on COVID-19 vaccines and mRNA vaccine expertise typically.
Though Kennedy agreed that Operation Warp Pace, President Donald Trump’s signature initiative to provide COVID-19 vaccines in 9 months, was an incredible achievement, he additionally maintained that COVID-19 vaccines trigger widespread and severe hurt, together with demise, notably in younger folks — a declare for which there isn’t a proof.
Some particularly pointed questions got here from Republican Sen. Invoice Cassidy of Louisiana, a doctor who supplied the ultimate vote wanted for Kennedy’s affirmation in February 2025 after Kennedy promised him that he wouldn’t change the Facilities for Illness Management and Prevention’s course of for recommending vaccines. Cassidy identified that with the limitations and confusion attributable to the CDC’s new guidelines round COVID-19 vaccines, “I’d say successfully we’re denying folks vaccines.” To which Kennedy replied, “Nicely, you are fallacious.”
On the listening to, Kennedy stood by his resolution to reduce US$500 million in HHS funding for 22 analysis contracts on mRNA vaccine expertise. HHS has mentioned it can as a substitute pour these funds into analysis on a conventional method to designing vaccines that was first used greater than 200 years in the past. With such vaccines, referred to as whole-virus vaccines, an individual’s immune system is offered with the entire virus, usually in weakened or inactivated kind. This switcheroo has puzzled many scientists.
A couple of days earlier than the listening to, on Sept. 1, Trump demanded that pharmaceutical firms show that COVID-19 mRNA vaccines work, saying that the CDC was “being ripped aside over this query.” It was his first public acknowledgment of the chaos roiling the CDC amid the firing of its director, Susan Monarez, and subsequent resignations of 4 high-level company officers.
In the meantime, public well being specialists and HHS staffers are calling for Kennedy to be fired, and a number of other senators on the listening to echoed that decision.
As a vaccinologist who has studied and developed vaccines for over 35 years, I see that the science behind mRNA vaccine expertise is being broadly misstated. This incorrect info is shaping long-term well being coverage within the U.S. — which makes it pressing to right the document.
Are mRNA vaccines much less protected than whole-virus vaccines?
HHS defended its cancellation of mRNA vaccine analysis primarily based, partly, on a nonpeer-reviewed compilation of chosen publications referred to as the COVID-19 mRNA “vaccine” harms analysis assortment. This doc lists about 750 articles claimed to explain harms attributable to mRNA vaccines in opposition to COVID-19. Nonetheless, the overwhelming majority of those articles aren’t about vaccines however concerning the harms of getting contaminated with SARS-CoV-2, the virus that causes COVID-19. And notably absent from it’s the enormous physique of information exhibiting mRNA vaccines truly stop these harms.
For instance, the doc getting used to justify RFK Jr.’s claims about mRNA vaccines highlights 375 research reporting that the virus’s spike protein alone, which is produced when the virus replicates, may cause extreme irritation and tissue injury. That is true. However the doc marshals this proof to help the declare that mRNA vaccines, that are designed to provide spike proteins, trigger the identical hurt — which isn’t correct.
Whereas viral replication ends in uncontrolled manufacturing of a big quantities of the protein, the way in which it is produced by the mRNA vaccine could be very completely different. The vaccine produces a small, managed quantity of spike protein inside just a few cells — simply sufficient to induce an immune response with out inflicting injury. And by blocking the virus’s replication, it reduces the quantity of spike protein in circulation, truly having the other impact.
What about unintended effects like myocarditis?
Early experiences flagged a sort of coronary heart swelling referred to as myocarditis as a uncommon aspect impact of the mRNA vaccine, notably for younger males ages 18 to 25 after a booster dose. A 2024 assessment recognized about 20 circumstances out of 1 million folks who acquired the vaccine. Nonetheless, that very same examine discovered that unvaccinated folks had an elevenfold greater threat of getting myocarditis after a COVID-19 an infection than vaccinated folks.
What’s extra, one other 2024 examine confirmed that individuals who developed myocarditis after vaccination had fewer problems than those that developed the situation after getting contaminated with COVID-19.
Do mRNA vaccines make the SARS-CoV-2 virus resistant?
One other declare from the compilation of supposed mRNA vaccine harms that was cited as a cause for chopping funding for mRNA expertise is that mRNA vaccines trigger mutations within the SARS-CoV-2 virus that make them resistant or much less prone to the vaccine.
When a virus replicates in its host, it produces tens of millions of copies of its genetic materials. Mutations are copying errors that happen naturally through the replication course of. These acquired mutations produce new variants, which is why each the COVID-19 mRNA and the whole-virus flu vaccine get up to date yearly — to maintain up with pure modifications within the virus.
Slowing down viral replication decreases the speed at which a virus can purchase new mutations. Since each mRNA and whole-virus vaccines cease or sluggish the virus from replicating, each sorts of vaccines assist scale back the emergence of resistant viruses.
Viruses can mutate to flee from antibodies, however the mRNA vaccines should not inflicting the emergence of extra virulent strains, possible for a minimum of two causes. First, mRNA vaccines induce immune responses that may assault the virus at a number of spots, so it must provide you with many mutations directly to flee the vaccine’s defenses. Second, even when the virus might purchase all these mutations, they’d possible weaken it, making it unable to trigger and even transmit illness.
mRNA vaccines versus new SARS-CoV-2 variants
Kennedy, in saying cuts to mRNA vaccine analysis on Aug. 5, 2025, claimed that mRNA vaccines do not work in opposition to respiratory viruses and that HHS was shifting towards “safer, broader vaccine platforms that stay efficient whilst viruses mutate.”
Each whole-virus vaccines and mRNA vaccines protected in opposition to COVID-19 and prevented hospitalization and demise for tens of millions of individuals worldwide between 2020 and 2024, however there’s clear proof that the mRNA-based vaccines supplied considerably higher safety than whole-virus vaccines. And for COVID-19, mRNA vaccines are more practical in opposition to new variants, which emerge as viruses mutate, than whole-virus vaccines.
The COVID-19 mRNA vaccines began with exceptionally excessive efficacy, exceeding 94%. When the SARS-CoV-2 delta and omicron variants emerged within the spring and fall of 2021, mRNA vaccines grew to become much less efficient in stopping infections. Nonetheless, they remained extremely efficient in stopping extreme sickness, whereas in unvaccinated folks the charges of extreme sickness and hospitalization remained excessive.
It is because mRNA vaccines induce the immune system to make each antibodies and specialised immune cells referred to as T cells. These parts can acknowledge a number of elements of the virus, together with ones that do not change, enabling important safety in opposition to new variants.
What’s extra, the mRNA vaccines have a superpower that no different kind of vaccine can presently match: They are often shortly up to date and manufactured inside two to 3 months. To develop a whole-virus vaccine, researchers should first spend months isolating and propagating the virus. Conversely, making an mRNA vaccine requires simply sequencing the virus’s genetic code — a course of that at this time takes simply hours.
If a brand new pandemic started at this time, mRNA vaccines are presently the one kind of vaccine that could possibly be developed shortly sufficient to disrupt its unfold.
The way forward for mRNA vaccine applied sciences
Thirty years in the past, when scientists first began creating mRNA vaccine expertise, they acknowledged its potential to beat main limitations of whole-virus vaccines — specifically, sluggish manufacturing time and extra restricted capability to guard from new viral variants. Right this moment, mRNA vaccines are additionally being developed to stop or deal with illnesses together with HIV and most cancers, in addition to autoimmune and genetic illnesses.
After all, this expertise might be additional improved. New mRNA vaccine applied sciences are aimed, amongst different issues, at making mRNA vaccines simpler to retailer to permit for sooner distribution and scale back their short-term unintended effects, get rid of the uncommon threat of myocarditis and extra shortly block a respiratory an infection.
The Nationwide Institutes of Well being is funneling cash away from new mRNA applied sciences towards a single undertaking creating common vaccines primarily based on conventional whole-virus vaccine expertise. Common vaccines are urgently wanted to offer broader safety in opposition to ever-changing respiratory viruses, akin to influenza, which are main pandemic threats.
A 2022 examine in mice and ferrets confirmed {that a} common flu vaccine NIH plans to help has promise. Nonetheless, a number of research of potential common flu vaccines primarily based on mRNA expertise present much more potential. Such vaccines might induce broader immunity than whole-virus vaccines by eliciting antibody and T-cell responses that goal a good wider vary of flu viruses.
It is exhausting to sq. these advantages with the truth that HHS and NIH have named the deliberate new common vaccine platform “Technology Gold Commonplace,” insisting that it represents a brand new commonplace in science and transparency. The hassle appears extra akin to eliminating all e-bike expertise and telling everybody who seeks one to get by with a single model of a 10-speed bike: Attending to the meant vacation spot should be potential, however will probably be slower and tougher.
And within the case of abandoning mRNA vaccine analysis, it could result in lives needlessly misplaced, whether or not because of potential medicines untapped or to pandemic unpreparedness.
This text was up to date to incorporate particulars from Kennedy’s Sept. 4, 2025, listening to.
This edited article is republished from The Dialog below a Inventive Commons license. Learn the unique article.
