This makes two weeks in a row with vaccine cases. Last week we discussed yet another Constitutional challenge against mandatory vaccination. This week we look at Nguyen v. Sec’y of Health and Human Services, 2026 U.S. Claims LEXIS 1650 (U.S. Ct. Fed. Claims June 22, 2026), a federal circuit Vaccine Act compensation case. Such cases are infrequently interesting, but this one contains one of the most thorough take-downs of case reports as poor quality scientific evidence that you will likely ever see.
The claim in Nguyen, which was rejected, was that a hepatitis B vaccine caused the plaintiff to suffer from a neurological condition, Guillain-Barré syndrome (GBS). Because GBS was not listed on the relevant Vaccine Table, this was a non-table injury case (duh), and thus the plaintiff had to satisfy “traditional causation standards” (not so duh). More specifically, the plaintiff needed to present preponderant evidence of (1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect; and (3) a temporal relationship between vaccination and injury. The court accepted that the plaintiff met the requirement of temporal relationship (the GBS hit the plaintiff between two and five weeks after the vaccination). So that’s one out of the three requirements being met. But that’s it. And, riffing off the old Meatloaf song, one of three is bad.
The court did not see a logical cause and effect scenario, so that was bad news for the plaintiff — bad enough to end the case. But the court devoted most of its analysis to the medical causation theory, and there the plaintiff had serious problems.
First, the plaintiff proffered a neurological expert with fine qualifications in the field of neurology, but the real issue here was immunology. The mismatch between expertise and the issue at hand was viewed by the court as a “detriment” to the plaintiff’s case. The defense expert, too, was a neurologist, not immunologist. That, too, is a detriment, but it is the plaintiff, not the defendant, who “bears the burden of presenting a persuasive case.”
Then the Nguyen court carefully analyzed both the case law and epidemiology on vaccination causation of GBS. The plaintiff’s proposed biological mechanism was “molecular mimicry,” which had support that could be characterized as frail at best. The epi studies either involved a different vaccine or reliance on an unreliable database (described in another case as a “stocked pond”), and discredited experts. At most, the plaintiff could claim a standoff on epidemiology – again, that is not enough to meet the plaintiff’s burden.
That leaves us with case reports and case series. This is the part of the case that will most gladden the flinty hearts of defense hacks. A case report equals mere anecdote, and “anecdote” is not the singular of “data.” Other Federal Circuit cases considering vaccine claims have “endorsed, albeit indirectly, a view that case reports merit little weight.” The Nguyen court does a good job of collecting many cases discounting case reports, both in and out (e.g., the Abilify MDL) of the vaccine program. Then, “in accord with these judicial authorities,” the Nguyen court declined to give the plaintiff’s “case reports much, if any weight.” Even beyond the general principle that case reports are weak, the particular ones cited by the plaintiff were especially off the mark.
The Nguyen court directly confronted another case that came to a contrary result. The “primary difference” between the cases was the weight of case reports, and the Nguyen court held that the weight was too little to permit the plaintiff to proceed with the vaccine compensation claim. Naturally, we side with the Nguyen case and give a bitter side-eye to the more lenient, permissive, pro-plaintiff case.
For any case you work on in which the evidentiary value of case reports is an issue, Nguyen is worth review and citation.
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