FDA Refuses Moderna mRNA Flu Vaccine Submission

Today the FDA is refusing an application for an mRNA flu vaccine, for reasons which are as deadly as they are astoundingly stupid.

They Did What?!

Remember Moderna? The company that made one of the mRNA vaccines for COVID-19?

They’ve had a robust research program numerous clinical development programs for things other than just COVID-19: several cancer vaccines, some disease vaccines, and in particular a flu vaccine.

• Their flu vaccine trial involved 40,000 people, starting 2024-Sept.
• The trial design was previously accepted by the FDA, and by the medical regulatory authorities in every other nation on the planet where it was simultaneously submitted. (That appears to include at least the European Union, Australia, and Canada.)
• It seems to be at least somewhat superior to existing flu vaccines in people over age 50. It was, in fact, 27% more effective vs symptomatic flu, and 49% more effective vs hospitalization.

That “demonstration of non-inferiority to standard of care” is the gold standard: you compare against how we’d usually treat a disease, and see if you can do better. Trials like this are designed in conjunction with the FDA, who usually give a couple of years of advice on how to do it the way that’s best for them. It’s never a surprise to the FDA when you submit a clinical trial result, since they helped you design it in the first place.

So it was with some alarm today that the FDA has refused even to consider the submission of the Moderna flu vaccine trial results, via an AP article. ^[1] That was sufficiently alarming to be worth checking to make sure other outlets in and out of the US news bubble agreed, so here are some pointers to The Guardian ^[2] and the “ol’ reliables” at STAT News, Matthew Herper and Helen Branswell. ^[3]

So, ok. I’m satisfied this is real news. It is, however, extremely unusual!

I have never seen a “refusal to review” letter when the agency had previously approved the trial. Apparently the objection is, in the words of FDA vaccine director Vinay Prasad, that the trial was not an “adequate and well-controlled trial” because the standard of comparison wasn’t the FDA’s preferred flu vaccine. This is also extremely unusual, since that was hashed out a couple years ago and the FDA agreed that the control vaccine used in the trial was ok and gave it the green light.

The consequences will be absolutely damning, going beyond medical risk to research risk in not pursuing vaccines in the future. As The Guardian put it:

“This is likely to discourage industry from investing in future influenza vaccines, and makes working with the US FDA uncertain and problematic,” said Dorit Reiss, professor of law at UC Law San Francisco.

“They are refusing to review a new vaccine with a more flexible technology, while creating a real risk we will not have traditional vaccines for next year.”

Future vaccine innovation will almost immediately move overseas.

Moderna has just announced exactly that, additionally killing projects because the US no longer makes it possible to break even on their current vaccine candidates for Epstein-Barr virus, herpes simplex virus, and shingles virus. These cures are now lost to humanity; even when governments change it may take generations to rebuild the capacity now being destroyed:

And, of course, infectious diseases are not the only things being lost. There are some very good cancer vaccines in the pipeline; in fact, immuno-oncology was perhaps the most promising area when I retired from oncology in 2020. Some of the results are startlingly good:

… but, apparently no more. It seems Moloch demands even more lives be sacrificed, with Republicans salivating to trade more lives for short-term power in their base.

It appears ^[4] that the FDA scientists were fine with Moderna’s trial, but were overruled personally by Trump/Kennedy protégé Vinay Prasad, who is currently the controversial head of the FDA Center for Biologics Evaluation and Research (CBER). The Wikipedia page on Prasad, linked here, notes that Prasad tends to push emotional hot buttons and some of his writing has amounted to fearmongering.

So… it’s personal with Trump/RFKJr/Prasad, now.

The Reaction

Reaction among scientists has been swift and relentlessly negative, as you might expect.

And it’s not just me: here’s an article from renowned med-chem writer Derek Lowe, a man normally of somewhat conservative/libertarian leanings, who over the last few years has become as enraged against Republicans as your humble Weekend Editor. ^[5]

Last night brought news that the FDA has refused to review Moderna’s application for their new mRNA influenza vaccine, and more details have emerged so far today. All of them are infuriating.

Like me, he sees this as extremely unusual, rising to “unheard-of” territory:

Right off, let’s just make clear that an outright refusal-to-review rejection like this is quite unusual, since biopharma companies (large and small) typically work with the FDA during their trials to make sure that things are being run in a way that the agency finds acceptable. Why wouldn’t you?
…
It is especially unusual for a vaccine. If there is a prior example like this with the FDA, I am unaware of it. Moderna seems baffled by the decision in their public statements, and I can’t blame them.

And it really does seem to be some personal jihad down to Prasad:

It appears that the agency - well, Vinay Prasad - told the company that they did not run an adequate trial … Prasad signed the rejection letter personally, which is also something I’ve never heard of before, so draw your own conclusions.

The controls used by Moderna were absolutely reasonable, and even though the FDA a couple years ago had some suggestions, they signed off on these controls (GSK’s Fluarix quadrivalent vaccine for adults 50 or older).

Derek reaches about the same conclusions as me (emphasis added):

And let’s get real here: this application is being denied, personally by Vinay Prasad and against the recommendation of the FDA’s remaining experts, because he and the rest of the Trump administration are hostile to vaccines in general and to mRNA technology in particular. I don’t see how anyone can look at the statements and actions of the political appointees (from RFK Jr. on down) and come away with any other impression. We are deliberately walking away from the most advanced form of one of the most effective public health measures available to the human race…

Like so many of the Trump administration’s actions, this is simultaneously weird, dangerous, and profoundly stupid. And we are all going to pay the price for it.

Now, I can already hear the objection that this is just the opinion of some weird, hippy scientists, and who cares what the longhairs think? (Let the record show that my hair is considerably longer than Derek’s.)

How about The Wall Street Journal? Is that sufficiently anti-hippy to pass your conservative purity tests? Because the WSJ coverage ^[6] points the finger of blame directly at Prasad, and is subtitled, “Does the White House know the harm he’s doing to public health?”

It doesn’t let up, either, with this opening paragraph:

It’s hard to recall a regulator who has done as much damage to medical innovation in as little time as Vinay Prasad. In his latest drive-by shooting, the leader of the Food and Drug Administration’s vaccine division rejected Moderna’s mRNA flu vaccine without even a cursory review. This is arbitrary government at its worst.

They report that Prasad wanted Moderna to have used a high-dose flu vaccine in the control arm. This is not even possible:

• In the US, those are only for seniors over 65. This trial was about people over 50, for whom the high-dose vaccines would have been medically inappropriate.
• The high-dose vaccines are not even available in Europe, where the trial was largely conducted.

So Prasad demands a medically inappropriate & not legally available control vaccine, thereby making it impossible for the trial to be conducted.

But Of Course, We’ll Always Have… Ivermectin?!

Instead, we are apparently funding a trial of ivermectin in cancer, of all things. ^[7]

Lots of things kill cancer. Usually they do so at doses that kill normal tissue, too. Normal scientists know this. Trump/RFKJr/Prasad apparently do not, or are willing to pretend not to know it.

This is pure political appeasement to the Trump base, who have a superstitious attachment to ivermectin. Incorrigibly persistent readers of this Crummy Little Blog That Nobody Reads (CLBTNR) will recall that, in the past, we’ve had vehemently negative things to say about the right-wing superstitions around ivermectin. ^{[8] [9] [10] [11] [12]}

Let’s be clear about a few things:

• Ivermectin is a perfectly reasonable drug for treating worm infestations, lice, and other invertebrate parasites.

  If you’ve got worms, this might be the drug for you. In the US, worms in humans are rare but it’s widely used for veterinary purposes, hence the name “horse paste”.

• Ivermectin does not treat COVID-19, and never has.

  The hints otherwise came from clinical trials conducted in countries where worm infestations were common. Worm infestations make everything worse. So if you have worms and COVID-19, ivermectin will help a little. (But what you really need in that case is ivermectin and paxlovid, because you have 2 separate problems.)

• Ivermectin is a “virtue signal” extremely strongly associated with right-wing disinformation.

  It’s so hard to get people to let go of ivermectin because they don’t want to lose their entire tribal identity as Trumpers or Republicans. It’s difficult to admit you’ve been conned!

But… now apparently the knuckleheads want to test ivermectin in cancer. The linked article points out that there is no evidence that ivermectin treats cancer. You will, of course, be unsurprised to hear that the new head of the National Cancer Institute (NCI) is a Trumper.

You do not want to be in this clinical trial! The “treatment” arm is a nonsensical application of a de-worming drug, so your best bet would be to get in the control arm, where you’d get standard of care. Though… given Prasad’s fixation on placebos, maybe you’d get no treatment at all – in violation of every medical ethis code.

Internal NCI scientists have reacted about as you might think:

The decision by the world’s premier cancer research institute to study ivermectin as a cancer treatment has alarmed career scientists at the agency.

“I am shocked and appalled,” one NCI scientist said. “We are moving funds away from so much promising research in order to do a preclinical study based on nonscientific ideas. It’s absurd.”

Absurd.

And for that absurdity, we kill mRNA vaccines for infectious diseases and cancer.

The Weekend Conclusion

The rest of the world looks askance at the utter clownshod goings-on in the US. Here, for example, is a visualization from Visual Capitalist ^[13] of the relative rankings of countries by reputations, and how they changed from 2024 to 2025, i.e., after the advent of Trump.

• A couple oddities: Cuba & Venezuela are in the list on the left, but disappear. Instead, Taiwan and Kuwait suddenly appear on the right. Hmmm.

• The US in recent years has never been terribly highly ranked abroad. We are too violent, too impulsive, too superstitious, and too prone to demagoguery.

  Hence, on the left hand side, you see the US in about the middle at rank 30, between Brazil and Ukraine. So we’re not starting from a very reputable place.

• With the (re-)advent of Trump, our reputation abroad has plunged!

  We are now at position 48, between Kuwait and Kazakhstan.

  This is how the rest of the world sees us. Trump in particular, and Republicans in general, are not brave visionaries. They are incompetent, dangerous, and fascist.

We are ruled by ignorant children. Their understanding of science just superstition. Their every other thought is about acquiring & keeping power, regardless of who might be hurt. In this case, their performative fear of mRNA vaccines is an attempt to cement power in their superstitious base.

By forbidding a potentially superior vaccine while offering the most ignorant of excuses, they set up a situation where people will die. But if it’s in the service of Republican power, they probably think that’s acceptable. Moloch demands no less.

(Ceterum censeo, Trump incarcerandam esse.)

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Notes & References

1: L Neergaard & M Perrone, “Moderna says FDA refuses its application for new mRNA flu vaccine”, Associated Press, 2026-Feb-10. ↩

2: M Schreiber, “FDA declines to review Moderna application for new flu vaccine”, Guardian, 2026-Feb-10. ↩

3: M Herper & H Branswell, “FDA refuses to review Moderna’s influenza vaccine”, STAT News, 2026-Feb-10. ↩

4: L Lawrence, “Prasad overruled FDA staff to reject Moderna’s flu vaccine application”, STAT News, 2026-Feb-11. ↩

5: D Lowe, “An mRNA Refusal to File”, In the Pipeline blog at Science, 2026-Feb-11. ↩

6: WSJ Editorial Board, “Vinay Prasad’s Vaccine Kill Shot”, Wall St Journal, 2026-Feb-11.

NB: Regrettably paywalled; see archive copy here. ↩

7: R Pradhan, “National Cancer Institute studying ivermectin’s ‘ability to kill cancer cells,’ alarming career scientists”, STAT News, 2026-Feb-10. ↩

8: Weekend Editor, “Three Lessons from COVID”, Some Weekend Reading blog, 2021-Nov-08. ↩

9: Weekend Editor, “A Couple Ivermectin Takedowns”, Some Weekend Reading blog, 2021-Nov-19 ↩

10: Weekend Editor, “Ivermectin Revenant”, Some Weekend Reading blog, 2022-Mar-07. ↩

11: Weekend Editor, “Ivermectin vs Strongyloidiasis Paper Published”, Some Weekend Reading blog, 2022-Apr-18. ↩

12: Weekend Editor, “Missouri: Ivermectin Gag Order”, Some Weekend Reading blog, 2022-May-20. ↩

13: M Lu, “Ranked: Countries With the Best Reputations in 2025”, Visual Capitalist, 2025-Oct-06. ↩