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Title: Pseudo-Anaphylactic Reactions to Pfizer BNT162b2 Vaccine: Report of 3 Cases of Anaphylaxis Post Pfizer BNT162b2 Vaccination
Authors: Lim, Xin Rong
Leung, Bernard Pui 
Ng, Carol Yee Leng
Tan, Justina Wei Lynn
Chan, Grace Yin Lai
Loh, Chien Mei
Tan, Gwendolyn Li Xuan
Goh, Valerie Hui Hian
Wong, Lok To
Chua, Chong Rui
Tan, Sze Chin
Lee, Samuel Shang Ming
Howe, Hwee Siew
Thong, Bernard Yu Hor
Leong, Khai Pang
Keywords: Science & Technology
Life Sciences & Biomedicine
Medicine, Research & Experimental
Research & Experimental Medicine
Issue Date: 1-Sep-2021
Publisher: MDPI
Citation: Lim, Xin Rong, Leung, Bernard Pui, Ng, Carol Yee Leng, Tan, Justina Wei Lynn, Chan, Grace Yin Lai, Loh, Chien Mei, Tan, Gwendolyn Li Xuan, Goh, Valerie Hui Hian, Wong, Lok To, Chua, Chong Rui, Tan, Sze Chin, Lee, Samuel Shang Ming, Howe, Hwee Siew, Thong, Bernard Yu Hor, Leong, Khai Pang (2021-09-01). Pseudo-Anaphylactic Reactions to Pfizer BNT162b2 Vaccine: Report of 3 Cases of Anaphylaxis Post Pfizer BNT162b2 Vaccination. VACCINES 9 (9). ScholarBank@NUS Repository.
Abstract: Anaphylactic reactions were observed after Singapore's national coronavirus disease 2019 (COVID-19) vaccination programme started in December 2020. We report the clinical and laboratory features of three patients in our institution who developed anaphylactic reactions after receiving the Pifzer BNT162b2 vaccine. IgM and IgG antibodies, but not IgE antibodies to the Pfizer BNT162b2 vaccine, were detected in all subjects. Similarly, mild to high elevated levels of anti-polyethylene glycol (PEG) IgG (1035-19709 U/mL, vs. vaccine-naive < 265 U/mL, vaccine-tolerant < 785 U/mL) and IgM (1682-5310 U/mL, vs. vaccine-naive < 1011 U/mL, vaccine-tolerant < 1007 U/mL) were detected in two out of three patients via commercial ELISA. High levels of serum anaphylatoxin C3a (79.0 ± 6.3 μg/mL, mean ± SD, vs. normal < 10 μg/mL) were observed in all three patients during the acute phase of the reaction, while tryptase levels, a marker of mast cell activation, were not elevated. Finally, one patient with the highest levels of anti-PEG IgG, IgM, and anti-Pfizer BNT162b2 IgG and IgM exhibited an enhanced Th2 cytokine serum profile during an acute reaction, with high levels of IL-4 (45.7 pg/mL, vs. vaccine-naive/tolerant < 2.30 pg/mL), IL-33 (86.4 pg/mL, vs. vaccine-naive/tolerant < 5.51 pg/mL) and IL-10 (22.9 pg/mL, vs. vaccine-naive/tolerant < 12.49 pg/mL) diminishing over time following corticosteroid treatment. Taken together, we propose these cases of anaphylaxis described are driven by a complement activation-related pseudoallergy (CAPRA), rather than classical IgE-mediated mechanisms.
Source Title: VACCINES
ISSN: 2076393X
DOI: 10.3390/vaccines9090974
Appears in Collections:Staff Publications

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