Table 2. Number and proportion of samples virus positive by participant characteristics, in a primary school in coastal Kenya, year 2017–18.

Characteristic		Any virus positive		Virus negative		P value
Age category	N	n	%	n	%
2–4	127	38	29.9	89	70.1
5–9	855	216	25.3	639	74.7
10–14	538	93	17.3	445	82.7
15–20	206	37	18.0	169	82.0	<0.003 *
Sex
Male	834	212	25.4	622	74.6
Female	892	172	19.3	720	80.7	0.037 *
Class level
Lower primary	982	254	25.9	728	74.1
Upper primary	744	130	17.5	614	82.5	<0.001 *
Grade
Daycare	178	65	36.5	113	63.5
Kindergarten1	>178	43	24.1	135	75.8
Kindergarten2	252	58	23.0	194	77.0
Kindergarten3	233	53	22.8	180	77.2
Grade 1	141	35	24.8	106	75.2
Grade 2	88	15	17.1	73	83.0
Grade 3	107	30	28.0	77	72.0
Grade 4	127	23	18.1	104	81.9
Grade 5	128	21	16.4	107	83.6
Grade 6	110	13	11.8	97	88.2
Grade 7	106	18	17.0	88	83.0
Grade 8	78	10	12.8	68	87.2	0.001 *
School term
2017 term 2	767	134	17.5	633	82.5
2017 term 3	417	102	24.5	315	75.5
2018 term 1	542	148	27.3	394	72.7	<0.001 *
Symptoms
Cough	1280	287	22.4	993	77.6	0.385 *
Runny nose	1511	346	22.9	1165	77.1	0.370 *
Sore throat	350	75	21.4	275	78.6	0.535 *
Class size
<=45 students	589	161	27.3	428	72.7
> 45 students	1137	223	19.6	914	80.4	<0.001 *
*BMI
Underweight	343	81	23.6	262	76.4
Normal	1336	297	22.2	1039	77.8
Overweight	47	6	12.8	41	87.2	0.156 *

* Weighted estimate *BMI- Body Mass Index