In less than three weeks, American medicine produced two milestones worth noticing.
On Aug. 5, the Food and Drug Administration approved MFLUSIVA, Moderna’s influenza vaccine for adults 50 and older — the first flu vaccine in the United States built with messenger RNA, or mRNA.
Two weeks later, Moderna and Merck announced positive Phase 3 results for an individualized mRNA treatment intended to keep high-risk melanoma from returning after surgery. It was the first positive Phase 3 result for an mRNA-based cancer therapy.
That second achievement deserves some explanation.
Messenger RNA is essentially a temporary set of biological instructions. For this treatment, scientists analyze mutations in an individual patient’s tumor and create an mRNA therapy designed to teach that patient’s immune system what to attack. It is not a preventive vaccine like a flu shot. It is a therapeutic cancer vaccine personalized to one patient’s tumor.
The therapy was added to Keytruda, Merck’s widely used immunotherapy, which helps the immune system attack cancer by releasing one of the brakes tumors can place on it. Keytruda is already a standard treatment for high-risk melanoma. The remarkable finding is that adding the personalized mRNA therapy produced better results than Keytruda alone.
That is extraordinary science. But it is not finished science.
Moderna and Merck have announced top-line findings, not the complete dataset. The details still need to be presented and scrutinized by scientists, and ordinarily published for peer review. If the results hold up, they could support an application to the FDA, which would independently decide whether the benefits justify the risks. A successful Phase 3 trial — the large, late-stage study generally intended to provide evidence for regulatory decisions — is an important milestone. It is not an approval.
Science does not stop when the press release comes out.
Nor does every mRNA experiment succeed. Moderna’s Phase 3 norovirus vaccine recently failed to meet the statistical criteria for early success, and the company is continuing the study.
One program disappointed. Another produced an approved influenza vaccine. A third has now produced a potentially historic cancer result.
These developments matter beyond mRNA. They illustrate what happens when new medical evidence collides with conclusions policymakers have already reached.
Science begins with a question, develops a hypothesis, and designs an experiment that gives that hypothesis a fair chance to fail. Then we live with the result. Public policy should come afterward.
That is why these medical milestones sit awkwardly beside Health and Human Services HHS Secretary Robert F. Kennedy Jr.’s rhetoric.
Last year, Kennedy’s HHS ordered BARDA to wind down 22 mRNA vaccine-development investments worth nearly $500 million. BARDA — the Biomedical Advanced Research and Development Authority — is the federal program that helps develop vaccines and other medical countermeasures against pandemics and national health threats.
Kennedy said the “data show these vaccines fail to protect effectively against upper respiratory infections like COVID and flu” and that HHS was “moving beyond the limitations of mRNA.”
One year later, his own FDA approved an mRNA vaccine against influenza.
That apparent contradiction is worth examining rather than merely scoring as a political point. Earlier this year, the FDA initially refused to review Moderna’s flu vaccine application because of concerns about the trial design, then reversed course and accepted it. In June, FDA’s outside vaccine advisers unanimously concluded that MFLUSIVA’s benefits outweighed its risks. The FDA approved it in August.
From outside HHS, we cannot know how much that reflects Kennedy deliberately giving FDA scientists room to work, how much reflects leadership changes within FDA, or simply the normal regulatory process asserting itself. If Kennedy allowed the evidence to lead even when it complicated his prior assumptions, he deserves credit.
But the same principle must apply elsewhere.
I have argued in these pages that enthusiasm for unapproved peptides cannot substitute for evidence and later that patient demand and influencer medicine cannot replace rigorous trials.
The standard should not change depending on whether politicians are enthusiastic about a treatment or skeptical of it. What should remain constant is the standard of proof.
Kennedy’s own HHS calls for “Gold Standard Science” built on reproducibility, transparency, constructive skepticism, falsifiable hypotheses, peer review, and acceptance of negative results.
Those are admirable principles. But skepticism is not evidence, and suspicion is not a result.
That matters because the administration is now reshaping childhood vaccine policy. President Donald Trump has called for reducing the number of vaccines routinely recommended for children and separating the measles, mumps, and rubella vaccine into individual shots. HHS is also seeking public input on new recommendation categories, including vaccines recommended “with qualification” or “but not during infancy.”
There is nothing wrong with revisiting vaccine policy. Medical recommendations are not scripture. Better evidence should be able to change, narrow, or overturn them.
But the evidence must come first.
The melanoma result does not vindicate every mRNA product. The norovirus setback does not condemn the technology. And MFLUSIVA’s approval does not mean the next mRNA vaccine deserves approval.
Kennedy says he wants gold-standard science. MFLUSIVA may show what that actually looks like: scientists ask the question, the data answer it, and policymakers accept the result — even when it complicates what they previously believed.
WE FINALLY HAVE ALZHEIMER’S BREAKTHROUGHS. WHY IS WASHINGTON HOLDING THEM BACK?
Childhood vaccine policy deserves the same discipline.
Science does not promise us the answer we want. It gives us a way to discover the answer we do not yet know.
Arie Blitz, M.D., M.B.A., is a retired physician and independent writer in Weslaco, Texas, who writes on foreign policy, medical ethics, and public policy.