Second Circuit Defines PREP Act “Causal Relationship” (No Sole-Cause Requirement) and Holds Denials of PREP Act Immunity Immediately Appealable; CUTPA Cannot Recast Medical Malpractice

I. Introduction

Waters v. Kory (2d Cir. Aug. 26, 2026) arises from remote COVID-19 treatment provided by Pierre Kory, M.D., to Edward James Waters, an elderly Connecticut patient. Kory prescribed high-dose prednisone to treat COVID-19 but did not prescribe medications (e.g., a proton pump inhibitor) to mitigate known gastrointestinal risks associated with prolonged/high-dose corticosteroid use. Waters later developed a perforated ulcer, suffered multiple organ failure, and died.

Waters’s estate sued for (1) negligence, (2) lack of informed consent, and (3) violations of the Connecticut Unfair Trade Practices Act (“CUTPA”). The central appellate issues were:

  • Whether the PREP Act’s immunity provision barred the negligence and informed-consent claims; and
  • Whether the CUTPA claim was, in substance, a professional-negligence claim barred by Connecticut law limiting CUTPA claims against health-care providers to entrepreneurial/business misconduct.

The Second Circuit answered both questions “yes,” reversed the district court’s refusal to dismiss under PREP Act immunity, affirmed dismissal of the CUTPA claim, and remanded.

II. Summary of the Opinion

  • Appellate jurisdiction: The court held that denial of a motion to dismiss based on PREP Act immunity is an immediately appealable collateral order. It also accepted jurisdiction over the CUTPA dismissal under Rule 54(b).
  • PREP Act immunity: Kory qualified as a “covered person,” prednisone was a “covered countermeasure” when used to treat COVID-19, and the complaint alleged “a causal relationship” between the prednisone prescription and Waters’s death sufficient to trigger PREP Act immunity. The court expressly rejected any “sole cause” requirement.
  • CUTPA: The estate’s CUTPA allegations targeted the quality of medical care and thus amounted to an impermissible attempt to repackage malpractice as a consumer-protection claim. Connecticut law requires CUTPA claims against medical professionals to be directed at the “business or entrepreneurial aspects” of practice, not medical competence.

III. Analysis

A. Precedents Cited

1. Pleading posture and standards of review

  • Schiebel v. Schoharie Cent. Sch. Dist. (120 F.4th 1082 (2d Cir. 2024)) supplied the familiar Rule 12 posture: on a motion to dismiss, the complaint’s well-pleaded facts are taken as true.
  • Ogunkoya v. Monaghan (913 F.3d 64 (2d Cir. 2019)) and Warney v. Monroe County (587 F.3d 113 (2d Cir. 2009)) anchored de novo review of a denial of immunity at the motion-to-dismiss stage.
  • Elias v. Rolling Stone LLC (872 F.3d 97 (2d Cir. 2017)) supplied the standard for de novo review of a Rule 12(b)(6) dismissal of the CUTPA count.

2. Appellate jurisdiction: collateral order doctrine

The court’s first major doctrinal move was jurisdictional: recognizing an immediate appeal from denial of PREP Act immunity. It built this holding by situating PREP Act immunity among classic “immunity from suit” doctrines.

  • Maye v. City of New Haven (89 F.4th 403 (2d Cir. 2023)) was cited for the court’s obligation to assure itself of appellate jurisdiction.
  • Petrello v. White (533 F.3d 110 (2d Cir. 2008)) framed the baseline “final decision” rule under 28 U.S.C. § 1291.
  • In re Décor Holdings, Inc. (86 F.4th 1021 (2d Cir. 2023) (per curiam)), quoting Germain v. Conn. Nat'l Bank (930 F.2d 1038 (2d Cir. 1991)) and EM Ltd. v. Banco Cent. de la República Arg. (800 F.3d 78 (2d Cir. 2015)), provided the three-part collateral order test (conclusiveness, separateness, and effective unreviewability).
  • Will v. Hallock (546 U.S. 345 (2006)) and Digit. Equip. Corp. v. Desktop Direct, Inc. (511 U.S. 863 (1994)) supplied the Supreme Court’s caution against overexpanding collateral-order appeals while emphasizing the special status of statutory or constitutional immunities from suit.
  • Mitchell v. Forsyth (472 U.S. 511 (1985)), P.R. Aqueduct & Sewer Auth. v. Metcalf & Eddy, Inc. (506 U.S. 139 (1993)), and Van Cauwenberghe v. Biard (486 U.S. 517 (1988)) helped distinguish mere “avoid trial” arguments from true immunities where the value is avoiding litigation burdens altogether.
  • The court also cited its own immunity-collateral-order cases—Gingras v. Think Fin., Inc. (922 F.3d 112 (2d Cir. 2019)) and Rogers v. Petroleo Brasileiro, S.A. (673 F.3d 131 (2d Cir. 2012))—to show it routinely permits interlocutory appeals where immunity is a right not to be sued.
  • Importantly, the court resolved a question it had left open in Solomon v. St. Joseph Hosp. (62 F.4th 54 (2d Cir. 2023)) by holding PREP Act immunity denials are collateral orders.
  • The Second Circuit aligned itself with other circuits that had already reached the same conclusion: Dressen v. AstraZeneca AB (182 F.4th 1232 (10th Cir. 2026)) and Hampton v. California (83 F.4th 754 (9th Cir. 2023)), and it noted Goins v. Saint Elizabeth Med. Ctr. (No. 22-6070, 2024 WL 229568 (6th Cir. Jan. 22, 2024) (unpublished)).

Influence on the decision: These authorities collectively enabled the court to characterize PREP Act immunity as “absolute immunity from suit,” making it “effectively unreviewable” if the defendant must litigate to final judgment—thus satisfying the collateral order doctrine.

3. Appellate jurisdiction: Rule 54(b) certification

  • Linde v. Arab Bank, PLC (882 F.3d 314 (2d Cir. 2018)) and Acumen Re Mgmt. Corp. v. Gen. Sec. Nat'l Ins. Co. (769 F.3d 135 (2d Cir. 2014)) provided the doctrinal requirements for partial final judgment under Rule 54(b).
  • In re Energetic Tank, Inc. (110 F.4th 131 (2d Cir. 2024)) and Scottsdale Ins. Co. v. McGrath (88 F.4th 369 (2d Cir. 2023)), with the “obvious reasons” exception supported by Brown v. Eli Lilly & Co. (654 F.3d 347 (2d Cir. 2011)), guided whether a district court must provide a reasoned explanation for certification.
  • Curtiss-Wright Corp. v. Gen. Elec. Co. (446 U.S. 1 (1980)), Novick v. AXA Network, LLC (642 F.3d 304 (2d Cir. 2011)), Harriscom Svenska AB v. Harris Corp. (947 F.2d 627 (2d Cir. 1991)), Hogan v. Consol. Rail Corp. (961 F.2d 1021 (2d Cir. 1992)), and Cullen v. Margiotta (618 F.2d 226 (2d Cir. 1980) (per curiam)) shaped the “no just reason for delay” analysis and the policy against piecemeal appeals.

Influence on the decision: These cases allowed the panel to approve Rule 54(b) certification largely because the PREP Act immunity issue was already properly on interlocutory appeal; reviewing the CUTPA dismissal concurrently promoted efficiency and reduced piecemeal appellate proceedings.

4. PREP Act causation and scope (including persuasive circuit authority)

  • Solomon v. St. Joseph Hosp. (62 F.4th 54 (2d Cir. 2023)) framed the PREP Act as a broad “immunity scheme,” quoted the statutory immunity text, and noted the administrative compensation alternative. The panel also used Solomon to reject attempts to reframe the dispute as a “preemption” case.
  • Maney v. Brown (91 F.4th 1296 (9th Cir. 2024)) was used to illustrate how the PREP Act’s list of covered activities (e.g., “design,” “manufacture,” “distribution”) reflects an “expansive causal relationship,” undermining any “sole cause” requirement.
  • Hampton v. California (83 F.4th 754 (9th Cir. 2023)) supported the proposition that, at minimum, the covered countermeasure must “have played some role” in bringing about the injury, and that “relating to” is not limitless when read in context.
  • Goins v. Saint Elizabeth Med. Ctr. (2024 WL 229568) was cited for the notion that covered countermeasures can include care addressing side effects of an affirmative countermeasure—again incompatible with “sole cause” thinking.
  • The panel distinguished “failure-to-use-countermeasure” cases via Schleider v. GVDB Operations, LLC (121 F.4th 149 (11th Cir. 2024)), noting that courts have held the PREP Act does not bar claims premised on a failure to administer a countermeasure, but emphasizing that this case alleged harm from an affirmative administration (prednisone).

5. Connecticut CUTPA and malpractice recasting

  • Haynes v. Yale-New Haven Hosp. (699 A.2d 964 (Conn. 1997)) served as the centerpiece: “Medical malpractice claims recast as CUTPA claims cannot form the basis for a CUTPA violation,” and the “touchstone” is whether the alleged misconduct concerns entrepreneurial/business aspects rather than medical competence.
  • Ulbrich v. Groth (78 A.3d 76 (Conn. 2013)) supplied CUTPA’s unfairness factors.
  • Janusauskas v. Fichman (826 A.2d 1066 (Conn. 2003)) and Est. of Doe v. Pegasus Mgmt. Co. (No. CV030082729, 2004 WL 944767 (Conn. Super. Ct. Apr. 14, 2004)) reinforced that allegations of profit motive or business pressures that degrade care typically remain malpractice in substance.

B. Legal Reasoning

1. New jurisdictional holding: PREP Act immunity denials are collateral orders

The court treated PREP Act immunity as a quintessential “immunity from suit,” not merely a defense to liability. Because the PREP Act confers “complete immunity from suit” (42 U.S.C. § 247d-6d(a)(1)), forcing a covered defendant to proceed through discovery and trial would destroy the core statutory protection. That characterization—rooted in Mitchell, P.R. Aqueduct, and Will—drove the “effectively unreviewable” prong and resulted in immediate appealability.

2. PREP Act framework applied

The panel applied a three-part structure derived from the statute and its declaration regime:

  • Covered person: A “qualified person” authorized under state law who prescribed/administered/dispensed a countermeasure (42 U.S.C. § 247d-6d(i)(2)(B)(iv), (i)(8)(A)). The court concluded Kory fit because Connecticut law (Conn. Gen. Stat. § 20-9(b)(5)) allowed limited temporary practice by an out-of-state physician, and the complaint’s timeline fit within the statute’s window.
  • Covered countermeasure: Prednisone qualified as a “drug” used to “treat” COVID-19 under the HHS declaration (85 Fed. Reg. 15198). The court emphasized that the PREP Act does not require a drug be specifically designed for COVID-19; it is enough that it was used to treat COVID-19 in the relevant context.
  • “A causal relationship”: The court’s key substantive holding: PREP Act immunity does not require that the countermeasure be the sole cause of the injury. It is enough that there is “a causal relationship” between the use/prescription and the loss (42 U.S.C. § 247d-6d(a)(2)(B)).

3. The Second Circuit’s causation clarification: no “sole cause” requirement

The opinion’s most significant interpretive contribution is its rejection of a narrow causation standard. The court grounded this in:

  • Statutory breadth: Immunity applies to claims “caused by, arising out of, relating to, or resulting from” administration/use (42 U.S.C. § 247d-6d(a)(1)), and extends to many upstream/downstream activities (labeling, packaging, marketing, etc.) in § 247d-6d(a)(2)(B), which rarely could be the “sole cause.”
  • Structural logic: The statute contemplates countermeasures addressing side effects of other countermeasures—conceptually incompatible with “sole causation.”
  • Textual minimalism: Congress required only “a causal relationship,” which the court read as deliberately expansive.

The court then found the pleaded facts comfortably satisfied any plausible remaining standard: the complaint alleged prednisone directly and foreseeably caused peptic ulcer disease that perforated and led to death, making it at least a factual and proximate cause.

4. Failure to prescribe prophylaxis did not avoid immunity

The district court had viewed the failure to mitigate prednisone’s side effects as “distinct and independent.” The Second Circuit rejected that characterization because the need for prophylaxis was triggered by the prescription of prednisone itself; the alleged omission was inseparable from administration of the covered countermeasure. The court therefore did not need to decide whether “distinct and independent cause” language (citing Mills v. Hartford Healthcare Corp.) has any place in PREP Act immunity analysis.

5. CUTPA: entrepreneurial vs. medical-competence distinction enforced

Applying Haynes v. Yale-New Haven Hosp., the court held the estate’s allegations—Kory’s branding, business growth, and alleged lack of time—were ultimately offered to prove deficient medical care. Connecticut CUTPA doctrine permits claims against medical providers only when directed at entrepreneurial/business practices separate from medical competence. Because the complaint’s gravamen was professional negligence, CUTPA could not be used as an alternate vehicle for recovery.

C. Impact

1. PREP Act litigation in the Second Circuit: earlier appellate resolution

By holding that denial of PREP Act immunity is an appealable collateral order, the court materially changes case trajectories: defendants can seek immediate appellate review before discovery and trial. This incentivizes early, statute-focused litigation over “covered person/countermeasure/causal relationship” and may increase interlocutory appeals in COVID-era treatment cases.

2. Substantive breadth of immunity: causation clarified

The court’s rejection of a “sole cause” requirement likely broadens immunity’s practical sweep. Plaintiffs often plead multiple contributing causes (dose, monitoring failures, failure to co-prescribe protective medications). Under Waters, such multi-factor pleadings do not necessarily avoid PREP Act immunity when the injury is causally connected to administration/prescription of a covered countermeasure.

3. Telehealth and off-label COVID treatment

Although the opinion is not framed as a telehealth decision, its application to remote prescribing signals that immunized “administration” or “prescribing” can occur through telehealth where state law authorizes the provider’s prescribing activity. Practically, this may shift more claims into the PREP Act compensation scheme rather than state-law tort litigation.

4. CUTPA boundary-policing continues

The decision reinforces that CUTPA is not a malpractice enhancer. Claims alleging profit motive, branding, marketing persona, or “too busy to provide proper care” remain vulnerable where they function only as explanations for poor clinical decisions. Plaintiffs will need to plead truly entrepreneurial misconduct (separable from clinical judgment) to survive dismissal.

IV. Complex Concepts Simplified

  • PREP Act immunity: A federal statute that, during a declared public health emergency, can bar lawsuits against certain people/entities for harms linked to the use of specified medical “countermeasures” (e.g., drugs, vaccines) unless a narrow “willful misconduct” path applies.
  • Covered person / qualified person: The statute protects certain actors (including licensed health professionals authorized under state law) when they prescribe/administer/dispense covered countermeasures.
  • Covered countermeasure: A product defined by the HHS Secretary’s declaration—here, a “drug” used to treat COVID-19.
  • “A causal relationship” (as used here): Not “the only cause.” It is enough that the countermeasure played a causal role in the alleged harm.
  • Collateral order doctrine: A narrow rule allowing immediate appeal of certain important orders that cannot be effectively reviewed after final judgment—commonly used for immunities from suit.
  • Rule 54(b): A mechanism allowing appeal of one fully resolved claim (like CUTPA) even while other claims remain pending, if the district court finds “no just reason for delay.”
  • CUTPA “entrepreneurial aspects” limitation: Connecticut permits CUTPA claims against medical providers only when the alleged wrongdoing concerns business/market conduct rather than the quality of medical judgment and care.

V. Conclusion

Waters v. Kory delivers two key doctrinal holdings for the Second Circuit: (1) denials of PREP Act immunity are immediately appealable collateral orders, and (2) PREP Act immunity requires only “a causal relationship,” not sole causation, between a covered countermeasure’s administration/prescription and the alleged loss. On the state-law side, the court reaffirmed that CUTPA cannot be used to repackage medical malpractice claims absent allegations directed at entrepreneurial/business misconduct distinct from medical competence.

The combined effect is to channel a broader set of COVID-countermeasure injury claims away from state tort litigation (and toward PREP Act mechanisms) while preserving Connecticut’s strict separation between malpractice and consumer-protection theories against health-care providers.