%0 Journal Article
%T A randomized double-blinded trial to assess recurrence of systemic allergic reactions following COVID-19 mRNA vaccination.
%A Khalid MB
%A Zektser E
%A Chu E
%A Li M
%A Utoh J
%A Ryan P
%A Loving HS
%A Harb R
%A Kattappuram R
%A Chatman L
%A Hartono S
%A Claudio-Etienne E
%A Sun G
%A Feener EP
%A Li Z
%A Lai SK
%A Le Q
%A Schwartz LB
%A Lyons JJ
%A Komarow H
%A Zhou ZH
%A Raza H
%A Pao M
%A Laky K
%A Holland SM
%A Brittain E
%A Frischmeyer-Guerrerio PA
%J J Allergy Clin Immunol
%V 153
%N 6
%D 2024 Jun 7
%M 38460680
%F 14.29
%R 10.1016/j.jaci.2024.03.001
%X <B>BACKGROUND: </B>Systemic allergic reactions (sARs) following coronavirus disease 2019 (COVID-19) mRNA vaccines were initially reported at a higher rate than after traditional vaccines.<BR><B>OBJECTIVE: </B>We aimed to evaluate the safety of revaccination in these individuals and to interrogate mechanisms underlying these reactions.<BR><B>METHODS: </B>In this randomized, double-blinded, phase 2 trial, participants aged 16 to 69 years who previously reported a convincing sAR to their first dose of COVID-19 mRNA vaccine were randomly assigned to receive a second dose of BNT162b2 (Comirnaty) vaccine and placebo on consecutive days in a blinded, 1:1 crossover fashion at the National Institutes of Health. An open-label BNT162b2 booster was offered 5 months later if the second dose did not result in severe sAR. None of the participants received the mRNA-1273 (Spikevax) vaccine during the study. The primary end point was recurrence of sAR following second dose and booster vaccination; exploratory end points included biomarker measurements.<BR><B>RESULTS: </B>Of 111 screened participants, 18 were randomly assigned to receive study interventions. Eight received BNT162b2 second dose followed by placebo; 8 received placebo followed by BNT162b2 second dose; 2 withdrew before receiving any study intervention. All 16 participants received the booster dose. Following second dose and booster vaccination, sARs recurred in 2 participants (12.5%; 95% CI, 1.6 to 38.3). No sAR occurred after placebo. An anaphylaxis mimic, immunization stress-related response (ISRR), occurred more commonly than sARs following both vaccine and placebo and was associated with higher predose anxiety scores, paresthesias, and distinct vital sign and biomarker changes.<BR><B>CONCLUSIONS: </B>Our findings support revaccination of individuals who report sARs to COVID-19 mRNA vaccines. Distinct clinical and laboratory features may distinguish sARs from ISRRs.