Table 1. Frequency of anti-PF4/polyanion... | American Society of Hematology

Table 1.

Frequency of anti-PF4/polyanion IgG in vaccinated individuals

Vaccine	BNT162b2	ChAdOx1 nCoV-19	Total
Total (%)	143 (50.9)	138 (49.1)	281 (100)
Age, y (median)	43	45	44
Female (%)	107 (74.8)	99 (71.7)	206 (73.3)
Postvaccination PF4/polyanion EIA⁺ (%)	8 (5.5)	11 (8.0)	19 (6.8)
SeCo substudy (n, %)	111 (47.4)	123 (52.6)	234 (100)
Postvaccination PF4/polyanion EIA⁺ (%)	7* (6.3)	10* (8.1)	17* (7.3)
Baseline samples available	3	6	9
Baseline PF4/polyanion EIA⁺ (%)†	2	4	6
AICOVI substudy (n, %)	32 (68.1)	15 (31.9)	47 (100)
Postvaccination PF4/polyanion EIA⁺ (%)	1 (3.1)	1 (6.7)	2 (4.3)
Baseline PF4/polyanion EIA⁺ (%)	0 (0)	1 (6.7)	1 (2.1)

Vaccine	BNT162b2	ChAdOx1 nCoV-19	Total
Total (%)	143 (50.9)	138 (49.1)	281 (100)
Age, y (median)	43	45	44
Female (%)	107 (74.8)	99 (71.7)	206 (73.3)
Postvaccination PF4/polyanion EIA⁺ (%)	8 (5.5)	11 (8.0)	19 (6.8)
SeCo substudy (n, %)	111 (47.4)	123 (52.6)	234 (100)
Postvaccination PF4/polyanion EIA⁺ (%)	7* (6.3)	10* (8.1)	17* (7.3)
Baseline samples available	3	6	9
Baseline PF4/polyanion EIA⁺ (%)†	2	4	6
AICOVI substudy (n, %)	32 (68.1)	15 (31.9)	47 (100)
Postvaccination PF4/polyanion EIA⁺ (%)	1 (3.1)	1 (6.7)	2 (4.3)
Baseline PF4/polyanion EIA⁺ (%)	0 (0)	1 (6.7)	1 (2.1)

Eight participants who tested positive after vaccination had no available baseline sample (4 with BNT162b2 and 4 with ChAdOx1 nCoV-19).

Only participants with positive PF4/polyanion EIA after vaccination who had an available baseline sample before vaccination were tested.