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P. Gresele et al.
Table 2. Cases of vaccine-induced immune thrombotic thrombocytopenia reported in the literature as of July 17, 2021.
Vaccine VITT Female,
Platelet count nadir-range x109/L
8-107
10/70
13/22a 7/113 1/23 NRb
Age range, years
22-49 32-54 21-77 25-32 55
51
60 22-46 54 41-67 63 69 50 37-50 24-53 25-32 62 30 30 29-50 41 36 51 38 50 35 54 36 44 27 63 30 24-39 53-61
48 18-<60l 40
18-77
Negative anti PF4,
n (total)
0/9
Time form vaccination range, days
References
cases, n
ChAdOx-1 11 ChAdOx-1 5 ChAdOx-1 23 ChAdOx-1 2 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 3 ChAdOx-1 1 ChAdOx-1 5 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 2 ChAdOx-1 7d ChAdOx-1 2 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 4f ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 1 ChAdOx-1 2 ChAdOx-1 3 Ad26.COV2.s Ad26.COV2.s 1 Ad26.COV2.s 12 Ad26.COV2.s 1
TOTAL 105
n (%)
9(82%) 4(80%) 14(61%) 0(0%) 1(100%) 1(100%) 1(100%) 3(100%) 1(100%) 5(100%) 0(0%) 1(100%) 0(0%) 1(50%) 4(57%) 0(0%) 1(100%) 1(100%) 1(100%) 3(75%) 1(100%) 1(100%) 0/1(0%) 0/1(0%) 0/1(0%) 1(100%) 0(0%) 1(100%) 0(0%) 0(0%) 0(0%) 0(100%) 2(100%) 2(66.6)%
1(100%) 12(100%) 1(100%)
73(69.5%)
CVST, n/total
2/2 7/17 0/1 0/1c 30 1/1 0/1 37 0/0 0/1 5 0/1 3/3 60-92 0/3 1/1 NR 0/0 1/5 12-105 0/5 0/1 36 0/1 1/1 18 0/1 1/1 15 0/0 1/2 7-9 0/2 4/7 8/71 0/7 2/2 19-30 1/1 0/1e 19 0/1 1/1 56 0/1 0/1 72 0/1 1/4 24-110 0/4 1/1 36 0/1 1/1 94 0/0 1/1 NRh 1/1 1/1 14 0/1 1/1 15 0/1 1/1 50 0/1 1/1 34 0/1 0/1 133 0/1 0/1 6 0/1 1/1 68 0/1 0/1 36 0/1 1/1 37 0/1 2/2 29-36 0/2 2/3 21-25 0/3
0/1 13 1/1 7/12 9-127 0/11 1/1 20 0/1 65/105 (62%) 5-133 5/92
Heparin-treated with success, n/treated
0/1 0/1 1/1 0/1 0/3 3/3 0/1 (1) 0/1 0/0 0/2 NR 0/1 0/0 0/1 1/1 0/1g 0/0 0/1 1/1 0/0 0/0 0/0 0/0 0/1g 0/0 0/0 0/0 0/0 0/2 0/0g
1/1 NR/6 0/0 10(4)/41
ChAdOx-1
9/11 4/5
0/5
1/5 2(3)/5
5-16 2 5-30 4 6-24 3
6-9 S1 10 6 11 5
7 S2 4-17 S3 12 S4 5-11 S5 20 S6 11 S7 11 S8 10 S9
6-20 S10 6-9 S11 8 S12 8 S13 8 S14 7-20 S15 7 S16 14 S17 6 S18 8 S19 7 S20 14 S21 21 S22 17 S23 8 S24 2 S25 20 S26 7 S27 8-12 S28 10-16 S29
14 1 6-15 12 5 S30
2-30 -
The reference numbers preceded by an S refer to references listed in the Online Supplementary Material.aOne patient had only thrombocytopenia.bThe patient was reported to be thrombocytopenic.cBilateral superior ophthalmic vein thrombosis.dAn eighth case included in this series was reported in reference S10.eNo thromboses were detected (pos- sibly not a VITT). fOne of the cases did not have thrombosis. gOne case was initially treated with full dose low molecular weight heparin, with no apparent worsening, and was then changed to a non-heparin anticoagulant upon identification of positive anti PF4 antibodies. hThe platelet count was stated to be normal. iAges are reported as ranges, not individual. NR:notreported;PF4:plateletfactor4;VITT:vaccine-inducedimmunethromboticthrombocytopenia.
administration of high doses of IgG in combination with steroids has been proposed for autoimmune HIT.77
Very early after the first reports of unusual types of thrombosis associated with the Vaxzevria vaccine, a German group suggested a tentative pathogenic mecha- nism underlying these rare events, which they named VIPIT, based on findings in nine cases of previously vac-
cinated subjects.11 Indeed, in sera from four of these sub- jects the investigators detected antibodies to PF4/heparin complexes using an enzyme-immunoassay; these anti- bodies were inhibited by the addition of high concentra- tions of heparin (i.e., 100 U/mL), and the sera were able to activate washed control platelets when either PF4 or the Vaxzevria vaccine was added in vitro to the samples.11
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