Second-dose mRNA COVID-19 vaccine safety in patients with immediate reactions after the first dose: A case series.

Background: The rates of suspected allergic reactions to the first dose of the coronavirus disease 2019 (COVID-19) mRNA vaccines have been reported to be as high as 2%, with an anaphylaxis incidence up to 2.5 per 10,000 individuals. Anaphylaxis in response to the first dose may be considered a contraindication to administration of the second dose, even though the second dose is necessary for optimal protection against severe disease. Many individuals with anaphylactic reactions to the first dose still want to receive a second dose. However, there are few published data to support the safety of administration of a second dose in this population. Objective: The primary objective of this study was to determine the percentage of patients tolerating a second COVID-19 mRNA vaccine dose after an immediate reaction to the first dose. Methods: This was a retrospective chart review of 47 patients at a Canadian hospital who had immediate, suspected allergic reactions following their first COVID-19 mRNA vaccine dose and received a second dose within our allergy clinic. Results: Of 47 patients, 46 tolerated the second dose; 43% of patients developed mild, transient symptoms. There were no patients who developed anaphylaxis or needed epinephrine after the second dose. Conclusion: Our case series adds to current evidence that administration of a second COVID-19 mRNA vaccine dose has a good safety profile in patients with a history of immediate reactions after the first dose, including those with a history of anaphylaxis in response to the first dose.

Hereditary angioedema: health-related quality of life in Canadian patients as measured by the SF-36.

BACKGROUND: Hereditary angioedema (HAE) is a rare but serious condition characterized by recurrent spontaneous attacks of angioedema affecting superficial tissues of upper respiratory and gastrointestinal tracts. The potentially fatal and disfiguring nature of HAE impacts the health-related quality of life (HRQoL) of patients with this condition. OBJECTIVES: To assess the health-related quality of life of Canadian patients with HAE using the 36-item Short-Form Health Survey (SF-36v2). METHODS: Twenty-one patients living in Canada over age 18 with known diagnosis of hereditary angioedema due to C1-INH deficiency (HAE), completed the SF-36v2 (generic HRQoL questionnaire). Results were compared to Canadian normative data by converting the SF-36 scores into z scores. RESULTS: The SF-36v2 showed a significant reduction in general health (p = 0.0063) in patients with HAE when compared with healthy Canadians. Percentage of patients with z scores below 0.8 (large effect) was 47.6% for general health subscale, 33.3% for bodily pain and vitality subscales and 28.6% for physical component scores. Mean scores of eight dimensions ranged from 57.7 to 88.9. Mean Physical and mental component scores were 49.1 and 50.4. Internal consistency of evaluation was demonstrated by Cronbach's alpha value above 0.7 for all scales. General perception of health was significantly different in these patients, compared to Canadian normative data. CONCLUSIONS: This study of Canadian patients with HAE shows that General Health is most frequently affected followed by Bodily Pain and Vitality, as measured by SF-36v2. The SF-36v2 offers valuable insight to assess quality of life in patients with HAE, however a larger number of Canadian patients and specific tools for assessment are needed for better evaluation.

Platelets in the immune response: Revisiting platelet-activating factor in anaphylaxis.

Anaphylaxis is an acute, severe, life-threatening multisystem allergic reaction resulting from the sudden systemic release of biochemical mediators and chemotactic substances. Release of both preformed granule-associated mediators and newly generated lipid-derived mediators contributes to the amplification and prolongation of anaphylaxis. Platelet-activating factor (PAF) is a potent phospholipid-derived mediator the central role of which has been well established in experimental models of both immune-mediated and non-immune mediated anaphylaxis. It is produced and secreted by several types of cells, including mast cells, monocytes, tissue macrophages, platelets, eosinophils, endothelial cells, and neutrophils. PAF is implicated in platelet aggregation and activation through release of vasoactive amines in the inflammatory response, resulting in increased vascular permeability, circulatory collapse, decreased cardiac output, and various other biological effects. PAF is rapidly hydrolyzed and degraded to an inactive metabolite, lysoPAF, by the enzyme PAF acetylhydrolase, the activity of which has shown to correlate inversely with PAF levels and predispose to severe anaphylaxis. In addition to its role in anaphylaxis, PAF has also been implicated as a mediator in both allergic and nonallergic inflammatory diseases, including allergic rhinitis, sepsis, atherosclerotic disease, and malignancy, in which PAF signaling has an established role. The therapeutic role of PAF antagonism has been investigated for several diseases, with variable results thus far. Further investigation of its role in pathology and therapeutic modulation is highly anticipated because of the pressing need for more selective and targeted therapy for the management of severe anaphylaxis.