Page 185 - Haematologica May 2022

Letters to the Editor
Immune thrombocytopenia following vaccination during the COVID-19 pandemic
To date, there have been over 3.2 million doses of ChAdOx1 nCoV-19 (ChAd) COVID-19 vaccine (AstraZeneca) and 1 million doses of BNT162b2 (BNT) COVID-19 vaccine (Pfizer-BioNTech) administered in Australia. Among the numerous safety signals that have been raised, we present our case series of immune throm- bocytopenia (ITP) after COVID-19 vaccination.1-4 ITP fol- lowing vaccination has been previously described in other settings and after mRNA-based COVID-19 vac- cines.5-8 A Scottish National Registry study examined general practice data and identified a small increased inci- dence of ITP diagnoses between days 0-27 after vaccina- tion with ChAD.9 We present the clinical characteristics and treatment outcomes of patients diagnosed with ITP following COVID vaccinations (ChAd or BNT) in Australia.
After obtaining independent ethics committee approval, we contacted hemostasis hematologists across
Australia to participate in our comprehensive survey of clinical presentations of vaccine-associated ITP as defined by the temporal relationship of ITP within 42 days fol- lowing COVID-19 vaccination, without an otherwise apparent alternative cause or thrombosis. Patients with thrombosis or elevated D-dimer levels were investigated and excluded for vaccine-induced immune-mediated thrombotic thrombocytopenia according to international guidelines.10 Response was defined as per international consensus guidelines as a platelet count ≥30x109/L, 2-fold increase over baseline and absence of bleeding. A com- plete response was defined as a platelet count ≥100x109/L and absence of bleeding.11
A total of 14 patients were diagnosed with ITP follow- ing vaccination. Twelve of these cases followed adminis- tration of the ChAd vaccine. Ten cases were de novo ITP, presented in Table 1. Four cases were relapses in patients with previously stable chronic ITP, presented in Table 2. None of the 14 patients had concurrent thrombosis. Among the 12 cases of ITP following administration of the ChAd vaccine, an enzyme-linked immunosorbent
Table 1. Demographics and clinical features of patients with newly diagnosed immune thrombocytopenia after COVID-19 vaccination.
Age Days COVID-19 Other Platelets at WHO Bleeding First-line Second-line TTR TTCR Platelets Treatments Other
and after gender vaccination
vaccine
1st ChAd 1st ChAd
1st ChAd
1st ChAd 1st ChAd
1st ChAd 1st ChAd
1st ChAd
1st BNT 2nd ChAd
antecedent vaccinations (30 days)
None Influenza
None
None None
None None
None
None
1st ChAd
given 4
weeks prior
presentation bleeding (and nadir score
if later) (x109/L)
treatment
Pred/IVIg Pred/IVIg
treatment
None 3 Eltrombopag 18
at day 30 (x109/L)
4 176 23 157
37 197
3 25 3 40
10 104 47 8
11 259
7 151 7 N/A
at day 30
Pred 5 mg daily Pred 75 mg daily
relevant history
None None
AML in remission (not on chemo)
None None
None
52M 80F
82M
60F 83F
61M 82M
86M
46M 22M
27 21
3
3 23
22 9
10
2 6
8 1 0 4
22 (1) 1
3 1 10 1
17 0 3 1
5 (3) 3
5 (0) 2 8 1
Petechiae
Life - threatening bleeding
Petechiae Pred/IVIg Eltrombopag 10
Pred 12.5 mg daily Eltrombopag 50 mg daily None None (Pulse Dex/IVIg repeated day 21) Pred 20 mg daily MMF 500 mg BD Dex pulse
Petechiae Dex/IVIg Pred Petechiae, Dex/IVIg None
ecchymoses
None Pred/MMF None
2 1
2 4
6
4 2
AIHA: autoimmune hemolytic anemia; AML: acute myeloid leukemia; BD: twice daily; BNT: BNT162b2 (Pfizer); ChAd: ChAdOx1 dexamethasone; F: female; IVIg: intravenous immunoglobulin; ITP: immune thrombocytopenia; M: male; MMF: mycophenolate time to response;WHO:World Health Organization.
nCoV-19 (AstraZeneca); COVID-19: coronavirus disease 2019; Dex: mofetil; Pred: prednisone; TTCR: time to complete response; TTR:
Purpura
Dex
Pred/IVIg
Pred
None
None N/A
Influenza repeated vaccination day 17
Major bleeding requiring hospitalization Mild blood loss
Pred 25 mg daily None
Pred 35 mg daily None N/A AIHA
Pred/IVIg Petechiae Pred/IVIg
after presenting with ITP
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