The FDA recently revoked the emergency use authorization for Regeneron and Eli Lilly. In this article, Ron Desantis claims that these medications led to “a huge decline” in hospitalization rates in Florida. He also claims that the EUA was revoked due to a “single non-peer reviewed, non-clinical study”.

Indeed, for months, Florida led the way in spreading the word about the treatments, which DeSantis said led to a “huge decline” in hospitalizations in the state. However, the Biden administration decided to revoke authorization of the treatment based on a “single non-peer reviewed, non-clinical study,” calling into question its effectiveness against the omicron variant.

Are these claims true?

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    Welcome to Skeptics!. Please quote the article directly. Given the reputation of the source, It seems possible to me that it twists the issue or that DeSantis said/meant something else; ie: that article isn't clear on who said what. Direct quote also needed to make this question standalone/protect against link rot. Jan 27, 2022 at 20:39
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    I added a quote, I'm not happy with the title but the whole claim doesn't really fit in there. The claim about the huge decline is also phrased as past tense, it doesn't even apply to Omicron. It might make more sense to focus on other claims in that article, but that's an edit I don't want to make myself.
    – Mad Scientist
    Jan 27, 2022 at 21:10
  • Thank you @MadScientist for adding the quote.
    – 1man
    Jan 27, 2022 at 21:26
  • Other articles around that with 'DeSantis' in body text make claim appear to be written as 'accepted tru fact' by the reporters, not as any type of quote by anybody. I see ways out: Ask about 'did Regeneron (or other specific monoclonals) reduce hospitalization hugely' (possibly removing DeSantis from Q) or find the direct quote by DeSantis (best if indeed he insists on 'these 2 would still reduce' (as omikron obsolesces these 2 mkABs, they might only effect lingering delta cases anyway?) Please remove "also claimed" & EUA-angle for focus on 'one claim—one Q'. Ask about them in new Q. Jan 27, 2022 at 21:54
  • 7
    Something to keep in mind: Even if the drugs had led to a huge decline that means nothing going forward because they don't work against the current cases. This is at best an example of deceiving the reader with selective truth. Jan 29, 2022 at 1:52

1 Answer 1


Did the drugs against COVID-19 whose EUA was revoked lead to a huge decline in hospitalization rates in Florida?

The FDA found that the treatment was effective enough to allow emergency use for previous strains. Whether it reduced hospitalizations before I cannot say, and if that was the claim I'd say close it for not being notable; ask on a medical forum.

Instead, let's look at the official press release: Governor DeSantis Condemns Biden Administration’s Haphazard Decision to Revoke Authorization of Lifesaving Monoclonal Antibody Treatments.

“Without a shred of clinical data to support this action, Biden has forced trained medical professionals to choose between treating their patients or breaking the law,” said Governor Ron DeSantis. “This indefensible edict takes treatment out of the hands of medical professionals and will cost some Americans their lives. There are real-world implications to Biden’s medical authoritarianism – Americans’ access to treatments is now subject to the whims of a failing president.”

Why would he condemn so bitterly revoking treatment which was reducing hospitalization rates, but isn't anymore?

De Santis's implication is that the treatment is still effective and that it is currently reducing hospitalization rates and that it the decision was made without evidence.

Let's look at De Santis's specific and notable claims surrounding the revocation.

The treatment is not currently reducing hospitalization rates

If the implied claim were correct, hospitalizations in Florida would sharply rise after the revocation.

By Jan 24th, hospitalizations had already peaked and were falling. No change in the hospitalization trend can be seen after Jan 24th.

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Source: John Hopkins Coronavirus Research Center

Florida hospitalizations appear to be following the national trend of the Omicron wave. For comparison, here is New York.

enter image description here

The FDA limited, not revoked, REGEN-COV's EUA because it is not effective against Omicron

On January 24th, 2022 the FDA limited use of Regeneron, it did not revoke it.

As of January 24, 2022, due to the high frequency of the Omicron variant, REGEN-COV is not currently authorized for use in any U.S. region because of markedly reduced activity against the omicron variant. Therefore, this drug may not be administered for treatment or post-exposure prevention of COVID-19 under the Emergency Use Authorization until further notice by the Agency.

Because REGEN-COV is an unapproved drug, the FDA must weigh its benefits vs its risks.

  • Monoclonal antibodies, such as REGENCOV, may be associated with worse clinical outcomes when administered to hospitalized patients with COVID-19 requiring high flow oxygen or mechanical ventilation.

The overwhelming majority of COVID hospitalizations are due to Omicron. The FDA limited REGEN-COV because it is no longer effective against Omicron making it no longer worth the risk to use an unapproved drug.

Specifically, the ability of REGEN-COV to neutralize VLPs expressing the spike protein of the Omicron variant was dramatically lower as compared to that of VLPs expressing the spike protein from the original strain of the virus.

The FDA still allowed uses of REGEN-COV for certain cases.

REGEN-COV co-formulated product and REGEN-COV supplied as individual vials to be administered together is authorized for emergency use for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients... with positive results of direct SARS- CoV-2 viral testing, and who are at high risk for progressing to severe COVID-19, including hospitalization or death.

If a patient is hospitalized for reasons other than COVID-19, such as for an elective orthopedic procedure, and the patient reports mild-to-moderate symptoms of COVID-19, confirmed with positive results of a direct SARS-CoV-2 viral test, then treatment with REGEN-COV may be appropriate, if the patient is also at high risk for progressing to severe COVID-19, including hospitalization or death, and the terms and conditions of the authorization are met...

REGEN-COV is not authorized for use in patients:

  • who are hospitalized due to COVID-19, or
  • who require oxygen therapy due to COVID-19, or
  • who require an increase in baseline oxygen flow rate due to COVID-19 in those on chronic oxygen therapy due to underlying non-COVID-19 related comorbidity.

The FDA decided to limit REGEN-COV by Regeneron's own data

The authorized monoclonal antibodies need to bind to the spike protein of the virus in order to neutralize the virus. Following the emergence of the Omicron variant, Regeneron assessed the activity of their product(s) against this variant and submitted these data to the FDA for review. Neutralization assays using virus-like particles (VLP) expressing SARS-CoV-2 spike proteins showed that REGEN-COV had marked reductions in neutralization activity. Specifically, the ability of REGEN-COV to neutralize VLPs expressing the spike protein of the Omicron variant was dramatically lower as compared to that of VLPs expressing the spike protein from the original strain of the virus. Using a measurement called neutralization, there was greater than 1000-fold reduction in the activity.

The FDA used the same criteria to allow its use and to limit its use

It is not clear to me if this is based on a "single non-peer reviewed, non-clinical study", but that is a red herring. De Santis trusted the FDA to say REGEN-COV was safe and effective, he should trust them now to say it is no longer effective.

REGEN-COV is an unapproved medication being used under an authorization for emergency. That lack of approval implies REGEN-COV has not undergone the full battery of studies and reviews, the emergency authorization is "based on the totality of the scientific evidence available to date".

Section 15 of the Fact Sheet For Health Care Providers EUA Of REGEN-COV has the details.

Casirivimab and imdevimab together retained activity against authentic SARS-CoV-2 variants of B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.617.1 (Kappa) lineages (Table 10), although casirivimab alone, but not imdevimab, had reduced activity against B.1.351 (5-fold), P.1 (>371-fold) and B.1.617.1 (6-fold) variants

Due to the large reduction of pseudotyped VLP neutralization activity against spike protein from the B.1.1.529/BA.1 (Omicron;South Africa origin) variant, it is unlikely that casirivimab and imdevimab together will be active against this variant.

tl;dr: the same tests which suggested it worked against earlier variants now say it doesn't work against Omicron.

If De Santis trusted the FDA's data and rationales before which said its effective enough to be worth the risk, he should trust those same rationales which now say it is not effective enough against omicron to be worth the risk.

  • 1
    The argument seems to be that the treatment is ineffective against Omicron specifically. A treatment that was effective for earlier variants could have reduced hospitalization rates pre-Omicron, but you'd see no change in hospitalization rates when restricting the treatment later on once Omicron was dominant. The lack of a rise in hospitalizations after the restriction suggests the treatment is indeed not effective for Omicron, but doesn't necessarily preclude that it was effective for earlier variants. Feb 16, 2022 at 20:57
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    @NuclearHoagie The claim (flipping it inside out) is that limiting the treatment lead to a rise in hospitalizations. It did not. And yes, that is why the FDA limited its use: it is not effective against Omicron, people are being hospitalized for Omicron. The treatment has risks and the risks outweigh its effectiveness against Omicron. The claim is not about earlier effectiveness. See section 15 of "Fact Sheet For Health Care Providers EUA Of REGEN-COV" for earlier effectiveness.
    – Schwern
    Feb 16, 2022 at 21:05
  • Absolutely agree that's the unstated and potentially misleading implication, that because it reduced hospitalization in the past, restricting it will result in a rise in hospitalizations. But I don't actually see that claim made anywhere, the question seems to be whether it's true that the treatment ever reduced hospitalizations, not whether it would continue to. As a parallel, claiming that the smallpox vaccine reduced deaths is very different from claiming that the elimination of routine smallpox vaccination should increase deaths. The "inside-out" claim is not the same. Feb 16, 2022 at 21:26
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    @NuclearHoagie I referenced De Santis's own Tweet and edited the question to make it clear what the notable claim actually is. A claim that it was effective is not notable on Skeptics, ask on a medical forum. Why would it be notable that the emergency authorization for a treatment which is no longer effective was revoked? Why would De Santis be so mad about revoking a treatment which no longer works?
    – Schwern
    Feb 16, 2022 at 21:28
  • It's also worth noting that the administration of REGEN-COV in Florida was not done in a way that allows an easy inference to be drawn about how much it decreased hospitalization. It might be possible to do a post-hoc analysis with a case-control study, but I would find it pretty iffy. The efficacy was determined by Regeneron's clinical trials and the FDA analysis, and those parties have agreed that it does not have efficacy against Omicron. It's not a lifesaving treatment anymore.
    – CJR
    Feb 16, 2022 at 21:29

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