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ANAPHYLAXIES AFTER EXPOSURE TO COVID-19 VACCINES:
A CASE SERIES

F. CHAHED, J. REBAI, H. BEN ROMDHANE, A. CHAABENE, K. AOUAM, N. BEN FREDJ, N.
BEN FADHEL
DEPARTMENT OF CLINICAL PHARMACOLOGY. FACULTY OF MEDICINE OF MONASTIR. UNIVERSITY
OF MONASTIR. TUNISIA

BACKGROUND: Vaccines against Covid-19 were recognized as one of the important
public health interventions to control the pandemic. Vaccines are supposed to supply
active immunity to unique antigens. Hypersensitivity reactions to Covid-19 vaccines
have been reported since the initiation of the vaccination campaigns. Severe
Anaphylaxis has been rarely described.

OBJECTIVE: To evaluate the particularities of severe anaphylaxis (grade III) after
exposure to covid-19 vaccine.
METHODS: We included all cases of severe anaphylaxis (grade III according to Ring
and Messmer Ring and Messmer Anaphylaxis Grading Scale) after Covid 19 vaccine
intake; notified to the Pharmacovigilance Unit of the Clinical Pharmacology
Department of the University Hospital of Monastir (Tunisia) between March 2020 and
January 2022. An allergy work up to suspected vaccines (skin tests to vaccines and
excipients; drug provocation test to polyethylene glycol) was performed. The
causative relationship between the hypersensitivity reaction and the vaccine
administration was established according to the probability scale of adverse drug
reactions published by Naranjo et al.

RESULTS: Six patients (4F/2M) were included in this study. The median age was 42
years (IQR: 27-72 years). Underlying atopy was presented in three patients. The
suspected Covid-19 vaccine was as follows: the mRNA vaccine (BNT162b2 (n= 3), and
inactivated virus vaccines (SinoVac: n= 2) and CoronaVac: n=1). The median time
interval between vaccination and the onset of anaphylactic reaction was 10 minutes
(2min- 12 hours). The offended dose was the first one in all patients. Four patients
agreed to undergo allergy work up. Skin tests were positive to only one patient
(Sinovac vaccine). Oral provocation test to the excipient (PEG) was performed in two
patients and revealed negatives.
Of all patients, none had the second booster dose to the offended vaccines.
Moreover, all patients refuse vaccination with another Covid-19 vaccine

CONCLUSIONS: Additional data are needed to evaluate the value of allergy work up
in the investigation of COVID-19 vaccine hypersensitivity.

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