Background:
Immunization with live attenuated viral
yellow fever vaccine (YFV)
grants effective
immunity in most cases, and is recommended and prioritized for residents and travelers of endemic countries. YFV is seldom administered to
egg-allergic
patients (EAP) since it is cultivated in embryonated
chicken eggs and may contain residual
egg proteins, being a problem for
egg-allergic residents and travelers of endemic countries.
Objective:
Describe the frequency of
allergic reactions after YFV
administration in confirmed EAP from an
allergy outpatient center in Bogotá,
Colombia.
Methods:
An observational, retrospective, cross-sectional, and descriptive study was conducted from January 2017 to December 2019. EAP whose
allergy was confirmed with a positive
Skin Prick Test (SPT) and/or
egg proteinspecific
IgE levels
who hadnt received the YFV were included. Every
patient had an SPT, severe EAP, and an additional
Intradermal Test (IDT) done with the
vaccine. If the
vaccine SPT and IDT were negative, the YFV was administered as a
single dose; if either were positive, the YFV was administered in graded doses.
Statistical analysis was done in Stata16MP.
Results:
Seventy one
patients were included, 24 (33.8%) of those had a
history of
egg anaphylaxis. All
patients had negative YFV SPTs, and two of the five YVF IDTs were positive. Two
patients, with previous
egg-
anaphylaxis, presented
allergic reactions to the
vaccine.
Conclusions:
YFV did not trigger
allergic reactions in EAP without
history of
egg-
anaphylaxis. With further
research, safe single-
dose vaccination to this
population could be considered; however,
patients with previous
egg-
anaphylaxis should be evaluated by an
allergist before
vaccination (AU)