“Last year’s influenza vaccine also contained the same H3N2 strain as this year’s vaccine (A/Hong Kong/4801/2014 (H3N2)-like virus). Many people would have developed long term IgE mediated sensitization to the H3N2 viral proteins due to last year’s vaccine [1–4]. Those who received the Flublok vaccine can be expected to have an even stronger IgE response due to its 3X viral protein content [5,4]. This year’s vaccine H3N2 proteins would have been neutralized by these IgE antibodies. Thus resulting in the observed low vaccine efficacy. You can read the full report here: https://www.bmj.com/content/360/bmj.k1378/rr-15
When a person making anti-H3N2 IgE is infected with H3N2, one can expect the course of the flu to be significantly worse. So the “cytokine storm” being observed in severe cases is likely to be an infection concurrent with an allergic reaction. Death is caused by anaphylactic shock but due to the presence of an infection, it is wrongly classified as septic shock.
In the case of food allergy for example, the allergen exposure can be large enough to cause an immediate hypersensitivity reaction and anaphylactic shock within minutes/hours. In the case of influenza allergy, it may take a day or two for the virus to replicate and produce enough viral exposure for anaphylaxis. So the anaphylaxis unfolds over a couple of days.
‘Self-reported vaccination for the current season was associated with a trend (P < 0.10) toward higher viral shedding in fine-aerosol samples; vaccination with both the current and previous year’s seasonal vaccines, however, was significantly associated with greater fine-aerosol shedding in unadjusted and adjusted models (P < 0.01). In adjusted models, we observed 6.3 (95% CI 1.9–21.5) times more aerosol shedding among cases with vaccination in the current and previous season compared with having no vaccination in those two seasons.’ ”