In re Zostavax (Zoster Vaccine Live) Products Liability Litigation

Anand Agneshwar, Jocelyn Wiesner & Tommy Huynh*

Why It Made the List

Whenever there is the prospect of a large litigation involving significant numbers of plaintiffs, the question of whether to move for a multi-district litigation (MDL) invariably arises. On the one hand, MDLs can provide a useful process to streamline pretrial proceedings before a single judge in one court, ensuring consistent application of law and coordination in discovery and motion practice. On the other, MDLs can encourage the filing of significant numbers of cases with varying levels of vetting, leading to inefficiencies and challenges for both defendants and plaintiffs. To combat this concern, the parties sometimes agree on case management orders (CMOs) that, with penalty of dismissal, require plaintiffs to provide basic evidence (often in the form of verified discovery responses) about their claims, such as product use, injury, and/or causation, at an earlier stage of the litigation. A number of MDL judges across the country have entered such orders, often resulting in the dismissal of cases that never would have survived individual causation challenges and ensuring that both plaintiffs and defendants have a more realistic picture of the scope of the litigation. Yet in some circles these orders remain controversial and some judges are reluctant to issue such orders in the absence of unanimous consent.

In re Zostavax (Zoster Vaccine Live) Products Liability Litigation[1] provides a very recent example of why these types of CMOs should be strongly considered in MDLs. There, the district court entered a CMO requiring 1,189 plaintiffs to present evidence of causation prior to summary judgment. The court recognized that because of the nature of the claim, many plaintiffs would be unable to prove causation regardless of the scope and extent of discovery. Accordingly, it decided to reshape the litigation.

The Third Circuit affirmed the order, endorsing the proposition that district judges should have wide latitude to enter case management orders that streamline the litigation and weed out claims that never should have been brought. It will be interesting to see whether defendants can successfully leverage Zostavax, as well as proposed new Federal Rule of Civil Procedure (FRCP) 16.1—which would encourage the early disclosure of MDL plaintiffs’ bases for their claims—to persuade even more MDL judges to adopt early vetting mechanisms that go beyond barebone requirements, including ones that require some kind of causation vetting up front.

The Facts

Varicella-zoster virus (VZV) causes chickenpox.[2] Once the chickenpox clears, however, the virus remains dormant in a person’s body for life. Because nearly everyone in the United States has had chickenpox, virtually everyone carries the dormant VZV wild-type strain.[3] If reactivated, it can cause shingles—a painful rash.[4]

Merck manufactured Zostavax, a vaccine that reduces the risk of developing shingles by exposing patients to the VZV attenuated strain.[5] Approximately 2,800 plaintiffs sued Merck, alleging that the Zostavax vaccine caused their shingles.[6] In August 2018, an MDL in the Eastern District of Pennsylvania before Judge Harvey Bartle was formed to adjudicate these cases.[7]

From 2018 to 2021, the parties worked up five bellwether cases for trial. All five involved plaintiffs who had chickenpox.[8] Following expert discovery, Merck successfully moved to exclude plaintiffs’ specific causation expert because he failed to rule out reactivation of the VZV wild-type strain as the alternative cause.[9] The court further granted Merck’s motion for summary judgment, dismissing all five bellwether cases, because they could not prove causation.[10]

Shortly thereafter, on January 2022, Merck moved for entry of a CMO requiring 1,189 plaintiffs to produce a PCR test,[11] which is the only way to reliably discern between the VZV strains,[12] and thus, the only way to tell whether Zostavax or chickenpox caused plaintiffs’ injuries. Plaintiffs opposed the motion, arguing that it would be impossible to comply because “none of the . . . [p]laintiffs had ever been PCR tested.” They further argued that because “PCR testing can only be done on existing [shingles] rashes, [and] most (if not all) of the . . . [p]laintiffs’ rashes had already healed,” the CMO would effectively require the dismissal of all plaintiffs subject to it.[13] The court disagreed and entered the order in March 2022.[14] After the PCR tests were not produced, the court dismissed 1,189 plaintiffs with prejudice.[15]

Plaintiffs appealed, arguing that the CMO was improper for two reasons: 1) it was entered “based purely on an assumption that PCR testing is the only way to establish specific causation”; and 2) it “mandated production of ‘non-existent evidence that never existed’ and was incapable of being created after-the-fact.”[16]

Analysis and Holding

In an unpublished opinion, the Third Circuit held the district court did not abuse its broad discretion in entering the CMO.

The Third Circuit rejected plaintiffs’ first argument, finding that the order was “premised on uncontradicted record evidence . . . that PCR testing is the only way to establish specific causation” rather than “on mere assumption.”[17] The court explained that plaintiffs had failed to produce any literature or expert opinion “explaining how it can be determined that Zostavax and not chickenpox caused a person to contract shingles other than through PCR testing” after three years—despite knowing from the start that they would have to exclude the VZV wild-type strain as the alternative cause.[18]

The Third Circuit also rejected plaintiffs’ second argument. As the Third Circuit explained, CMOs are not limited to requiring only “the production of evidence that already existed or can be created.”[19] Rather, the court reiterated that an MDL judge has wide latitude to structure orders in a form that helps dismiss meritless cases.[20] And because plaintiffs could not explain how they could prove specific causation without PCR tests,[21] there could be no unfairness because plaintiffs were never ultimately going to be able to prove specific causation.[22] In other words, the CMO accomplished exactly what it was intended to do: it required earlier vetting of cases so that the parties could focus time and resources on only those cases that are potentially meritorious.

The Impact

The Third Circuit’s affirmance of the CMO makes clear that MDL judges have wide discretion on how to weed out meritless claims. Such CMOs often utilize verified written discovery responses where, for example, product use is at issue. Here, the judge employed a novel approach requiring MDL plaintiffs to produce causation evidence in the form of a genetic test that did not already exist. Going forward, parties should think creatively about what actual evidence will be required to prove causation and consider a process to vet such evidence before either party spends significant time and resources litigating cases. This approach would be beneficial to both plaintiffs and defendants, as it would allow each side to take a more realistic assessment of the scope and value of a particular litigation.

The Zostavax decision comes on the heels of a proposed amendment to FRCP 16.1, which would encourage the early exchange of information in MDLs. Likely implemented in December if approved, proposed FRCP 16.1 suggests an initial conference to address “how and when the parties will exchange information about the factual bases for their claims and defenses.”[23] The Advisory Committee’s comments further state that the “court may find it appropriate to employ expedited methods to resolve claims or defenses not supported after the required information exchange.”[24] Defendants in MDLs should look for opportunities to leverage the broad discretion expressed in Zostavax, coupled with proposed FRCP 16.1, to persuade more MDL judges to adopt early vetting procedures.

While the Zostavax CMO ultimately dismissed many meritless cases before summary judgment, it was entered three years into the MDL and only after the burden and expense of working up five bellwether cases. The need for earlier, more robust vetting (as proposed FRCP 16.1 seems to acknowledge) is pressing in MDLs. As Zostavax illustrates, such claims could be disposed of earlier if proper vetting mechanisms are in place earlier.

* Anand Agneshwar co-chairs Arnold & Porter’s Product Liability Litigation practice group. He represents pharmaceutical and consumer product companies as national, strategic, trial, and appellate counsel in product liability and related litigation. Jocelyn Wiesner is Counsel in Arnold & Porter’s Product Liability Litigation practice group. She has extensive experience litigating pharmaceutical and medical device product liability actions, as well as consumer protection actions brought by state attorneys general. Tommy Huynh is a Senior Associate in Arnold & Porter’s Product Liability Litigation practice group. His practice focuses on representing pharmaceutical and consumer product companies in product liability and mass tort litigation.

[1]   In re Zostavax Prods. Liab. Litig., 2024 WL 3423709 (3d Cir. July 16, 2024).

[2]   Id. at *1.

[3]   Id.

[4]   Id.

[5]   Id.

[6]   Id.

[7]   Id.

[8]   Id.

[9]   Id.

[10] Id.

[11] Id. at *2, n. 17.

[12] Id. at *1–2.

[13] Id. at *2.

[14] Id.

[15] Id.

[16] Id.

[17] Id. at *3.

[18] Id.

[19] Id.

[20] See id.

[21] Id. at *4.

[22] See id.

[23] Proposed FRCP 16.1, https://www.uscourts.gov/sites/default/files/2024_scotus_package_‌final.‌pdf.

[24] Id.