Entitlement Decision – Aggravation of Susac’s Syndrome – Flu/DTaP


Means v. HHS, (Fed. Cl. Spec. Mstr. Oct. 13, 2015) (Dorsey, CSM)

Susac’s Syndrome is a condition diagnosed in patients who experience an identifiable triad of symptoms: an encephalopathy, branch retinal artery occlusion, and hearing loss.  It is an autoimmune endotheliopathy.  It can be mistaken for MS or ADEM.  Information regarding the pathogenesis and natural history of the disease is lacking, however, there is a working consensus that the disease is immune-mediated, as patients respond well to immunosuppressive treatment.

Because the Petitioner had experienced a headache in the several days prior to the vaccine, which was arguably the initial manifestation of Susac’s, the Court applied the Loving significant aggravation analysis. Prongs 1 and 2 or before/after, were relatively straightforward.  Regarding prong 3, whether the “after” constituted a significant aggravation, Respondent’s expert contended there was no evidence to support that vaccines could worsen an autoimmune disease already in progress.

The Court found that Petitioner had experienced a significant aggravation because, compared to case reports of the typical disease presentation over months or years before all clinical criteria are satisfied, Petitioner’s presentation was acute and severe.  He developed the classic triad of symptoms in only 20 days.  This supported Petitioner’s expert’s testimony that he was experiencing mild symptoms and would have had a mild course of the disease, before the vaccines.  Aside from the rapid progression of his clinical course after vaccination, the severity of his condition and clinical outcome, compared to case reports, also suggested a significant aggravation had occurred.

On Althen prong 1 (Loving 4), Petitioner advanced molecular mimicry and non-specific immune response as medical theories.  There appeared to have only been one relevant case report,  of a possible exacerbation of Susac’s following smallpox vaccine.  The court held that “petitioner’s theory of an aberrant adaptive immune response triggered by the vaccinations at issue, whereby an innate immune response began upon receipt of a flu vaccination on November 6, followed by an anamnestic immune response upon receipt of a Tdap vaccine the next morning, is supported by reliable evidence in this case.”  There is no indication from the opinion that homology evidence, or its lack, was discussed.

On Althen prong 2, the court was persuaded that Petitioner’s symptoms were distinct from the preexisting symptoms, and Petitioner experienced new symptoms of Susac’s after vaccination.  The court credited Petitioner’s expert’s opinion that petitioner’s vaccinations were “one substantial factor, among other factors”, which contributed to an exacerbation of petitioner’s condition.  It is not clear what the other factors were, or could have been.

On Althen Prong 3, timing, the major point of contention between the experts was whether vaccinations can trigger an exacerbation of an immune-mediated condition twenty-four to forty-eight hours after vaccination.  Respondent’s expert contended that a minimum of 7 days was required for the immune response.  However, Petitioner cited an IOM publication showing that an anamnestic response to an antigen previously encountered can occur in 1-3 days (the lag phase) and Petitioner had been vaccinated with DTaP as a child (see same analysis in Day v. HHS, also in this summary).  Respondent’s expert disagreed with this but did not cite any support to counter the IOM.

Thus, having satisfied all 6 prongs of Loving, Petitioner prevailed.

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