. 2021 Apr 15;26(15):2001695. doi: 10.2807/1560-7917.ES.2021.26.15.2001695

Table 3. SARS-CoV-2 infection attack rates (%) by symptoms and age category in schools in a city in northern France, 13 January–19 April 2020 (n = 2,004 participants).

Symptoms	Children < 12 years (n = 546)					Children 12–17 years (n = 313)					Adults (n = 1,145)
Symptoms	Number of individuals	Proportion with the symptom (%)	Number infected	Proportion with the symptom infected (%)	p value	Number of individuals	Proportion with the symptom (%)	Number infected	Proportion with the symptom infected (%)	p value	Number of individuals	Proportion with the symptom (%)	Number infected	Proportion with the symptom infected (%)	p value
Fever
Yes	121	22.2	13	10.7	0.30	84	26.8	33	39.3	0.03	254	22.2	81	31.9	< 0.001
No	425	77.8	33	7.8	0.30	229	73.2	61	26.6	0.03	891	77.8	85	9.5	< 0.001
Cough
Yes	124	22.7	8	6.5	0.37	105	32.9	32	30.5	0.90	349	30.5	87	24.9	< 0.001
No	422	77.3	38	9.0	0.37	208	66.5	62	29.8	0.90	796	69.5	79	9.9	< 0.001
Dyspnoea
Yes	20	3.7	3	15.0	0.28	33	10.5	5	15.1	0.05	157	13.7	49	31.2	< 0.001
No	526	96.3	43	8.2	0.28	280	89.5	89	31.8	0.05	988	86.3	117	11.8	< 0.001
Ageusia
Yes	4	0.7	0	0	0.99	19	6.1	17	89.5	< 0.001	94	8.2	76	80.9	< 0.001
No	542	99.3	46	8.5	0.99	294	93.9	77	26.2	< 0.001	1,051	91.7	90	8.6	< 0.001
Anosmia
Yes	2	0.4	0	0	0.99	20	6.4	16	80.0	< 0.001	85	7.4	76	89.4	< 0.001
No	544	99.6	46	8.5	0.99	293	93.6	78	26.6	< 0.001	1,060	92.6	90	8.5	< 0.001
Myalgia
Yes	40	7.3	4	10.0	0.71	55	17.6	19	34.5	0.42	268	23.4	83	31.0	< 0.001
No	506	92.7	42	8.3	0.71	258	82.4	75	29.1	0.42	877	76.6	83	9.5	< 0.001
Sore throat
Yes	90	16.5	8	8.9	0.86	87	27.8	25	28.7	0.76	261	22.8	53	20.3	0.002
No	456	83.5	38	8.3	0.86	226	72.2	69	30.5	0.76	884	77.2	113	12.8	0.002
Rhinorrhoea
Yes	97	17.8	10	10.3	0.46	114	36.4	41	36.0	0.08	283	24.7	62	21.9	< 0.001
No	449	82.2	36	8.0	0.46	199	63.5	53	26.6	0.08	862	75.3	104	12.1	< 0.001
Headache
Yes	101	18.5	8	7.9	0.84	91	29.1	31	34.1	0.32	332	29.0	84	25.3	< 0.001
No	445	81.5	38	8.5	0.84	222	70.9	63	28.4	0.32	813	71.0	82	10.1	< 0.001
Asthenia
Yes	79	14.4	11	13.9	0.06	77	24.6	26	33.8	0.41	350	30.6	95	27.1	< 0.001
No	467	85.5	35	7.5	0.06	236	75.4	68	28.8	0.41	795	69.4	71	8.9	< 0.001
Chest pain
Yes	0	0	0	0	NA	0	0	0	0	-	7	0.6	0	0	0.61
No	546	100	46	8.4	NA	313	100	94	30.0	-	1,138	99.4	166	14.6	0.61
Nausea
Yes	3	0.5	1	33.3	0.23	3	1.0	2	66.7	0.22	10	0.9	4	40.0	0.04
No	543	99.5	45	8.3	0.23	310	99.0	92	29.7	0.22	1,135	99.1	162	14.3	0.04
Vomiting
Yes	23	4.2	1	4.3	0.71	13	4.2	5	38.5	0.54	18	1.6	2	11.1	0.99
No	523	95.8	45	8.6	0.71	300	95.8	89	29.7	0.54	1,127	98.4	164	14.6	0.99
Abdominal pain
Yes	6	1.1	0	0	0.99	2	0.6	0	0	0.99	12	1.0	4	33.3	0.08
No	540	98.9	46	8.5	0.99	311	99.4	94	30.2	0.99	1,133	99.0	162	14.3	0.08
Diarrhoea
Yes	50	9.2	9	18.0	0.01	37	11.8	17	45.9	0.03	151	13.2	38	25.2	< 0.001
No	496	90.8	37	7.5	0.01	276	88.2	77	27.9	0.03	994	86.8	128	12.9	< 0.001
Symptom severity
None	274	50.2	20	7.3	0.62	110	35.1	22	20.0	0.01	429	37.5	14	3.3	< 0.001
Minor^a only	89	16.3	8	9.0		54	17.3	15	27.8		214	18.7	14	6.5
Major^b	183	33.5	18	9.8		149	47.6	57	38.3		502	43.8	138	27.5
Medical consultation^c
Yes	99	36.4	8	8.1	0.53	44	21.7	17	38.6	0.62	255	35.6	73	28.6	< 0.001
No	173	63.6	18	10.4	0.53	159	78.3	55	34.6	0.62	461	64.4	79	17.1	< 0.001
Hospitalisation
Yes	1	0.2	0	0	0.99	4	1.3	2	50.0	0.59	14	1.2	9	64.3	< 0.001
No	545	99.8	46	8.5	0.99	309	98.7	92	29.8	0.59	1,131	98.8	157	13.9	< 0.001

NA: not applicable.

^a Minor symptoms included asthenia, diarrhoea, headache, myalgia, rhinitis, and sore throat.

^b Major symptoms included ageusia and anosmia, fever, dry cough and dyspnoea.

^c Only among participants who declared symptoms, including children < 12 years (n = 272); children 12–17 years (n = 203); adults (n = 716).