Primary Care Provider-Reported Prevalence of Vaccine and Polyethylene-Glycol Allergy in Canada.

BACKGROUND: The COVID-19 pandemic has highlighted the importance of accurate capture of vaccine, and vaccine component, allergy. There remains a gap in the prevalence literature from the perspective of direct primary care provider (PCP) reporting at a population level. OBJECTIVE: To determine the prevalence of PCP-documented vaccine and polyethylene glycol (PEG) allergy using Electronic Medical Record (EMR) data from the Canadian Primary Care Sentinel Surveillance Network (CPCSSN). METHODS: Retrospective cohort study using the CPCSSN repository. Machine learning algorithms were applied to assess for vaccine allergy documentation, and ATC codes used for PEG allergy or allergy to common injectable medications containing PEG (CIMCP). RESULTS: The prevalence of PCP-documented vaccine allergy in Canada was 0.037%, (395/1,055,677) and of PEG allergy was 0.0009% (10/1,055,677). In total, 0.01% of patients had a documented allergy to either PEG or CIMCP (135/1,055,677). None of the patients with PEG allergy had a documented allergy to a CIMCP. Patients with vaccine allergy and PEG allergy were significantly more likely to have other atopic comorbidities including asthma (P<.0001 for both), eczema (P<.0001 and P=.001 respectively), rhinitis (P=.002 and P<.0001 respectively) and food allergy (P<.0001 for both). Significantly higher rates of depression (P=.0005 and P<.0001 respectively) and anxiety (P=.003 and P<.0001) were seen in those with vaccine allergy, or PEG allergy, compared to those without. CONCLUSION: This is the first study to estimate the prevalence of vaccine and PEG allergy in a national cohort that utilizes PCP documentation, demonstrating a low reported rate of vaccine allergy and PEG allergy.