Entitlement Decision – Neuromyelitis Optica After HPV and Flu Vaccine


Day v. HHS,(Fed. Cl. Spec. Mstr. Nov. 13, 2015) (Dorsey, CSM)

Neuromyelitis Optica (NMO) is a demyelinating autoimmune disorder consisting of optic neuritis and transverse myelopathy.  In NMO, the immune system becomes confused and begins to attack the body’s astrocytes rather than foreign pathogens, causing swelling in the brain and spinal cord.  NMO-IgG antibodies target aquaporin-4 (“AQP4”), a protein that is present in astrocytes and is found in the blood of NMO patients.  Because the triggering event that causes the NMO-IgG antibodies to attack the self is unknown, NMO is currently classified as an idiopathic disorder.

On prong 1 of Althen, Petitioners advanced a theory, supported by medical literature, that molecular mimicry explains the development of NMO after HPV vaccine, because there is homology between the L1 protein of HPV and the AQP4 protein.  Because that homology is limited, cross-reactivity is extremely rare, i.e., most people develop antibodies to non-homologous regions of the HPV protein and do not develop NMO.  Another paper supported the role of flu vaccine in NMO.

A major issue in this case was whether “short sequence” homologies, while potentially cross-reactive, were sufficient to induce autoimmunity.  Several studies supported the proposition that limited homologies can in fact induce autoimmunity, and the Special Master agreed.

With regard to prong 2, the Special Master was persuaded that the aging and location of the MRI lesions corresponded with the initial onset symptoms of NMO, post-vaccine.

Finally, on prong 3, the Court held that a 3-day onset was appropriate for a booster dose of HPV, given the prior exposure to antigen, based on the IOM’s discussion of lag phase and other pertinent articles on the appropriate interval for ADEM, an analogous condition.  Specifically, the “Risk Interval Working Group” observed that while the primary risk interval for studying adverse reactions to vaccines is approximately 5 to 28 days, 2 to 42 days was “biologically plausible” as a secondary risk interval.  Respondent’s expert did not counter this evidence, other than generally disagreeing.

Thus, Petitioner was entitled to compensation.

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