Safety of mRNA BNT162b2 COVID-19 (Pfizer-BioNtech) vaccine in children aged 5–11 years: Results from an active pharmacovigilance study in central Italy

Figures & data

Table 1. Adverse events among children following the receipt of each dose stratified by sex.

	First dose (N=229)				Second dose (N=199)				Reactions after I vs II dose
	Total n (%)	Female (N=116) n (%)	Male (N=113) n (%)	p-value	Total n (%)	Female (N=97) n (%)	Male (N=102) n (%)	p-value	p-value
At least one mild reaction	187 (81.7)	102 (87.9)	85 (75.2)	.013	139 (69.8)	77 (79.4)	62 (60.8)	.042	.004
Injection site pain/redness/swelling	182 (79.5)	101 (87.1)	81 (71.7)	.004	137 (68.8)	75 (77.3)	62 (60.8)	.012	.012
Tiredness/Asthenia	28 (12.2)	15 (12.9)	13 (11.5)	.742	9 (4.5)	7 (7.2)	2 (2.0)	.074	.005
Headache	30 (13.1)	15 (12.9)	15 (13.3)	.939	16 (8.0)	8 (8.2)	8 (7.8)	.916	.092
Chills	3 (1.3)	3 (2.6)	0 (0)	.085	4 (2.0)	3 (3.1)	1 (1.0)	.289	.862
Nausea	3 (1.3)	3 (2.6)	0 (0)	.085	2 (1.0)	1 (1.0)	1 (1.0)	.974	.769
Abdominal pain	5 (2.2)	4 (3.4)	1 (0.9)	.184	0 (0)	0 (0)	0 (0)	not applicable	.036
Fever <38°C	5 (2.2)	4 (3.4)	1 (0.9)	.184	4 (2.0)	2 (2.1)	2 (2.0)	.956	.899
Insomnia/Restlessness	9 (3.9)	4 (3.4)	5 (4.4)	.693	1 (0.5)	0 (0)	1 (1.0)	.328	.019
Sleepiness	8 (3.5)	6 (5.2)	2 (1.8)	.165	1 (0.5)	1 (1.0)	0 (0)	.303	.031
Decreased appetite	4 (1.7)	4 (3.4)	0 (0)	.046	1 (0.5)	0 (0)	1 (1.0)	.328	.232
At least one moderate reaction	9 (3.9)	4 (3.4)	5 (4.4)	.140	21 (10.6)	9 (9.3)	12 (11.8)	.568	<.001
Muscle/Joint pain	4 (1.7)	3 (2.6)	1 (0.9)	.325	1 (0.5)	0 (0)	1 (1.0)	.328	.232
Lymphadenopathy	1 (0.4)	1 (0.9)	0 (0)	.322	17 (8.5)	9 (9.3)	8 (7.8)	.717	<.001
Diarrhea	2 (0.9)	1 (0.9)	1 (0.9)	>.999	1 (0.5)	0 (0)	1 (1.0)	.328	.646
Localized rash	2 (0.9)	0 (0)	2 (1.8)	.150	3 (1.5)	1 (1.0)	2 (2.0)	.590	.542
At least one severe reaction	3 (1.3)	3 (2.6)	0 (0)	.085	1 (0.5)	1 (1.0)	0 (0)	.303	.387
Fever ≥39°C	1 (0.4)	1 (0.9)	0 (0)	.322	1 (0.5)	1 (1.0)	0 (0)	.303	.920
Paresthesia	1 (0.4)	1 (0.9)	0 (0)	.322	0 (0)	0 (0)	0 (0)	not applicable	.351
Clustered rash	1 (0.4)	0 (0)	1 (0.9)	.310	0 (0)	0 (0)	0 (0)	not applicable	.351

Legend: p-value were calculated using Chi-square test.

Table 2. Description of (a) onset and (b) resolution of adverse reactions after the first dose.

a) Onset	<1 h N (%)	1-4 h N (%)	4-12 h N (%)	12-24 h N (%)	24-48 h N (%)	>48 h N (%)	Total N
Mild
Injection site pain/redness/swelling	20 (11.0)	59 (32.4)	80 (44.0)	19 (10.4)	4 (2.2)		182
Tiredness/Asthenia		5 (17.8)	12 (42.9)	9 (32.1)	1 (3.6)	1 (3.6)	28
Headache	1 (3.3)	4 (13.3)	16 (53.4)	8 (26.7)		1 (3.3)	30
Chills			2 (66.7)			1 (33.3)	3
Nausea	1 (33.3)		2 (66.7)				3
Abdominal pain				2 (40.0)	2 (40.0)	1 (20.0)	5
Fever <38°C			2 (40.0)	3 (60.0)			5
Insomnia/Restlessness		2 (22.2)	4 (44.5)	3 (33.3)			9
Sleepiness			6 (75.0)	2 (25.0)			8
Decreased appetite			3 (75.0)		1 (25.0)		4
Moderate
Muscle/Joint pain		1 (25.0)	1 (25.0)	1 (25.0)		1 (25.0)	4
Lymphadenopathy				1 (100)			1
Diarrhea				1 (50.0)	1 (50.0)		2
Localized rash			2 (66.7)		1 (33.3)		3
Severe
Fever ≥39°C				1 (100)			1
Paresthesia		1 (100)					1
Clustered rash					1 (100)		1
b) Resolution		<12 h N (%)	12–24 h N (%)	24–48 h N (%)	48–72 h N (%)	>72 h N (%)	Total N
Mild
Injection site pain/redness/swelling		22 (12.1)	75 (41.2)	74 (40.7)	6 (3.3)	5 (2.7)	182
Tiredness/Asthenia		7 (25.0)	8 (28.6)	6 (21.4)	4 (14.3)	3 (10.7)	28
Headache		8 (26.7)	11 (36.7)	6 (20.0)	3 (10.0)	2 (6.7)	30
Chills				2 (66.7)		1 (33.3)	3
Nausea		1 (33.3)		2 (66.7)			3
Abdominal pain			3 (60.0)			2 (40.0)	5
Fever <38°C		1 (20.0)	1 (20.0)	2 (40.0)		1 (20.0)	5
Insomnia/Restlessness		2 (22.2)	4 (44.5)	1 (11.1)		2 (22.2)	9
Sleepiness		2 (25.0)	2 (25.0)	4 (50.0)			8
Decreased appetite			2 (50.0)		1 (25.0)	1 (25.0)	4
Moderate
Muscle/Joint pain		1 (25.0)		1 (25.0)	1 (25.0)	1 (25.0)	4
Lymphadenopathy				1 (100)			1
Diarrhea			2 (100)				2
Localized rash			2 (66.7)	1 (33.3)			3
Severe
Fever ≥39°C				1 (100)			1
Paresthesia		1 (100)					1
Clustered rash			1 (100)				1

The highest frequency for each event is reported in bold.

Table 3. Description of (a) onset and (b) resolution of adverse reactions after the second dose.

a) Onset	<1 h N (%)	1-4 h N (%)	4-12 h N (%)	12-24 h N (%)	24-48 h N (%)	>48 h N (%)	Total N
Mild
Injection site pain/redness/swelling	12 (8.8)	34 (24.8)	72 (52.6)	15 (10.9)	4 (2.9)		137
Tiredness/Asthenia		2 (22.2)	4 (44.4)	3 (33.4)			9
Headache	1 (6.2)	3 (18.8)	6 (37.5)	6 (37.5)			16
Chills			3 (75.0)	1 (25.0)			4
Nausea		1 (50.0)	1 (50.0)				2
Fever <38°C			1 (25.0)	3 (75.0)			4
Insomnia/Restlessness				1 (100)			1
Sleepiness				1 (100)			1
Decreased appetite		1 (100)					1
Moderate
Muscle/Joint pain				1 (100)			1
Lymphadenopathy			2 (11.8)	4 (23.5)	7 (41.2)	4 (23.5)	17
Diarrhea						1 (100)	1
Localized rash			2 (75.0)			1 (25.0)	3
Severe
Fever ≥39°C				1 (100)			1
b) Resolution		<12 h N (%)	12–24 h N (%)	24–48 h N (%)	48–72 h N (%)	>72 h N (%)	Total N
Mild
Injection site pain/redness/swelling		22 (16.1)	53 (38.7)	50 (36.5)	8 (5.8)	4 (2.9)	137
Tiredness/Asthenia			6 (66.7)	1 (11.1)	2 (22.2)		9
Headache		4 (25.0)	10 (62.5)	2 (12.5)			16
Chills		1 (25.0)	3 (75.0)				4
Nausea			1 (50.0)	1 (50.0)			2
Fever <38°C		1 (25.0)	2 (50.0)	1 (25.0)			4
Insomnia/Restlessness				1 (100)			1
Sleepiness			1 (100)				1
Decreased appetite				1 (100)			1
Moderate
Muscle/Joint pain			1 (100)				1
Lymphadenopathy			1 (5.9)	9 (52.9)	6 (35.3)	1 (5.9)	17
Diarrhea		1 (100)					1
Localized rash			2 (66.7)		1 (33.3)		3
Severe
Fever ≥39°C				1 (100)			1

The highest frequency for each event is reported in bold.