We had the pleasure of talking on a panel at ACI final week, together with dialogue of the terrific order from the Zantac MDL excluding all of the plaintiffs’ normal causation specialists.  That order primarily did away with a complete MDL and got here in fourth on our record of finest selections of 2022 .  Our totally pleasant panel dialogue of that Rule 702 order brought on us to return by way of the information to see if there have been different good skilled orders that we could have missed.  That assessment turned up an order from the Zostavax MDL that’s eminently blogworthy.

The order is In re Zostavax Merchandise Legal responsibility Litig., No. 18-md-2848, 2023 WL 6626581 (E.D. Pa. Oct. 11, 2023), and technically we didn’t “miss” it.  Bexis doesn’t miss something, and Lisa Baird posted a one-paragraph replace on this determination again when it got here out.  There are, nevertheless, a number of fascinating angles we thought we may amplify. 

The Zostavax MDL has been primarily about shingles, however as we reminded you all simply the opposite day, the shingles instances primarily went kaput as a result of the plaintiffs couldn’t show causation.  The leftovers have fared no higher, with the district courtroom dismissing a case alleging peripheral neuropathy and excluding skilled causation opinions on persistent day by day complications. 

The plaintiff within the order we’re overlaying right now alleged that he got here down with Guillian-Barré syndrome, a uncommon autoimmune dysfunction characterised by diffuse weak spot, simply days after he obtained a Zostavax vaccine.  However as we reported in our replace, the district courtroom excluded the plaintiff’s skilled on particular causation as a result of his differential prognosis didn’t move muster.  There are 4 factors we wished to focus on. 

First, the district courtroom handled normal causation first and concluded that the plaintiffs’ specialists’ reliance on epidemiological research (or extra precisely, one epidemiological research) was sound methodology.  The defendants clearly disagreed, and the courtroom freely acknowledged that there was scientific proof going the opposite approach.  However at the least the courtroom dominated on normal causation earlier than it engaged in a differential prognosis.  We have now seen courts skip that step altogether, leaving us to marvel how a defendant’s product might be “dominated in” as a possible trigger when it has not but been established that the product is able to inflicting the alleged damage within the first place.  This courtroom didn’t make that mistake. 

Second, the courtroom credited the specialists’ reliance on epidemiology, however threw severe shade on one skilled’s reliance on case experiences and opposed occasion experiences, that are “‘universally acknowledged as inadequate and unreliable proof of causation’ within the absence of different dependable proof.”  Id. at *5.  In different phrases, case experiences are anecdotal and are make-weight proof at finest.  Thus, whereas specialists can justifiably rely “partially” on them, “reliance on case experiences needs to be minimized as a result of they don’t have in mind the background price of illness.”  Id.

Third, the courtroom dominated that temporal proximity alone was inadequate to “rule in” the defendant’s vaccine as a possible trigger.  This can be a important ruling as a result of, in lots of instances, the solely foundation for the plaintiff’s case is that she or he skilled signs at a while after publicity to the defendant’s product.  Right here, the plaintiff’s particular causation skilled “dominated in” the vaccine primarily based on the brief time (three days) between when the plaintiff obtained the vaccine and when his signs started.  However that would have been a coincidence, and even the plaintiff’s skilled conceded that contracting Guillian-Barré syndrome “lower than one week after a triggering an infection is uncommon.”  Id. at *6.  The courtroom dominated that the skilled’s “ruling in” of Zostavax failed due to his “after this, due to this fact due to this” reasoning.  Id.

Fourth, the courtroom dominated that the plaintiff’s skilled’s differential prognosis was unreliable and inadmissible additionally as a result of he had not dominated out idiopathic causes.  This can be a important ruling too, as a result of many illnesses and situations happen for unknown or unexplained causes (see, for instance, mesothelioma).  This skilled admitted that roughly one-third of Guillian-Barré syndrome instances resulted from unknown or unexplained causes, and his personal scientific expertise was that one-half of the instances he had seen had been idiopathic.  Id. at *6.  But, the skilled didn’t rule out idiopathic causes in his differential prognosis, which doomed his opinions.  We don’t take this ruling essentially to imply that an skilled has to rule out idiopathic causes in each case.  When, nevertheless, a major variety of instances are idiopathic, it must be on the differential.

So take these helpful nuggets and run with them.  From a broader view, we’ll echo what we’ve stated earlier than—that this MDL appears to be on its final legs, with a hodgepodge of allege accidents and decide who’s proactively steering the leftovers to a dignified conclusion.  We are going to maintain you posted.