Analysis of the adverse events following immunization with inactivated quadrivalent influenza vaccine from 2018 to 2020 in Zhejiang province, with a comparison to trivalent influenza vaccine

Figures & data

Table 1. AEFI reporting rate of QIV and TIV in Zhejiang province from 2018 to 2020

Characteristics	QIV reports		TIV reports		χ^2	P
	No.	Reporting rate	No.	Reporting rate
Vaccine doses	3,762,337	13.66	4,095,522	13.09
Category					6.19	>0.05
Vaccine product-related reaction (minor)	362	9.62	372	9.08
Vaccine product-related reaction (severe)	48	1.28	55	1.34
Vaccination error	2	0.05	1	0.02
Coincidental event	97	2.58	104	2.54
Anxiety reaction	5	0.13	4	0.10
Severity*					4.68	>0.05
Severe	51	1.36	59	1.44
Minor	463	12.31	477	11.65

QIV: inactivated quadrivalent influenza vaccine; TIV: inactivated trivalent influenza vaccine; Reporting rate: /100,000 doses.

*:Severity of AEFI is assessed as minor or severe: (1) AEFI reports with no intervention necessary or with physician visit or event interfering with daily activities or loss of working hours are defined as minor; and (2) AEFI reports with any untoward medical occurrence that results in death, hospitalization, prolongation of hospitalization, persistent or significant disability/incapacity, life threatening, or birth defect are defined as severe.

Table 2. Characteristics of AEFI reports of QIV and TIV in Zhejiang province from 2018 to 2020

Characteristics	QIV reports			TIV reports			χ^2	P
	No.	%		No.	%
Type of reporter							2.55	>0.05
Health care provider	79	15.37		89	16.60
Patients or caregivers	420	81.71		420	78.36
Manufacturer	15	2.92		27	5.04
Onset from vaccination							3.41	>0.05
0–1d	396	77.04		411	76.68
2–3d	66	12.84		70	13.06
4–7d	35	6.81		37	6.90
8–14d	13	2.53		12	2.24
≥15d	4	0.78		6	1.12
Age group					0.00		1.88	>0.05
<18	77	14.98		83	15.49
18–49	128	24.90		133	24.81
≥50	309	60.12		313	58.40
Administrated alone	498	96.89		522	97.39

QIV: inactivated quadrivalent influenza vaccine; TIV: inactivated trivalent influenza vaccine.

Table 3. Clinical diagnosis of AEFI reports of QIV and TIV in children and adolescent aged 3–17 years from 2018 to 2020

Clinical diagnosis	QIV		TIV		P	ROR‑1.96SE (only for QIV)
	No. of AEFI reports	Reporting rate	No. of AEFI reports	Reporting rate
Aseptic abscess	1	0.08	1	0.07	>0.05	0.79
Allergic rash	5	0.39	8	0.57	>0.05	1.52
Allergic purpura	2	0.16	2	0.14	>0.05	0.72
Thrombocytopenic purpura	2	0.16	3	0.22	>0.05	0.86
Angioedema	1	0.08	1	0.07	>0.05	0.56
Guillain Barre Syndrome	1	0.08	0	0.00	>0.05	0.93
Epilepsy	2	0.16	0	0.00	>0.05	0.82
Febrile convulsion	4	0.31	4	0.29	>0.05	0.65
Syncope	1	0.08	1	0.07	>0.05	0.55
Fever/redness/induration	157	12.27	173	12.42	>0.05	0.83

QIV: inactivated quadrivalent influenza vaccine; TIV: inactivated trivalent influenza vaccine; Reporting rate: /100,000 doses.

Table 4. Clinical diagnosis of AEFI reports of QIV and TIV in adults ≥18 years from 2018 to 2020

Clinical diagnosis	QIV		TIV		P	ROR‑1.96SE
	No. of AEFI reports	Reporting rate	No. of AEFI reports	Reporting rate
Aseptic abscess	2	0.08	1	0.04	>0.05	0.76
Allergic rash	8	0.32	9	0.33	>0.05	1.42
Psychiatric	3	0.12	2	0.07	>0.05	0.66
Allergic purpura	1	0.04	2	0.07	>0.05	0.57
Thrombocytopenic purpura	2	0.08	2	0.07	>0.05	0.85
Angioedema	0	0.00	1	0.04	>0.05	0.77
Anaphylactic shock	1	0.04	1	0.04	>0.05	0.83
Asthma/wheezing	4	0.16	3	0.11	>0.05	1.26
Cardiovascular	1	0.04	1	0.04	>0.05	0.53
Guillain Barre Syndrome	1	0.04	2	0.07	>0.05	0.59
Epilepsy	0	0.00	1	0.04	>0.05	0.62
Febrile convulsion	1	0.04	2	0.07	>0.05	0.78
Syncope	2	0.08	5	0.18	>0.05	0.82
Bell’s palsy	3	0.12	3	0.11	>0.05	0.63
Fever/redness/induration	309	12.44	308	11.39	>0.05	0.71

QIV: inactivated quadrivalent influenza vaccine; TIV: inactivated trivalent influenza vaccine; Reporting rate: /100,000 doses.