Table 3.

Transmission events in participating household contacts in each setting

	Household size*	Number of child cases at start of swabbing†	Number of adult cases at start of swabbing	Number of naive contacts	Number of contacts testing positive				Naive contact crevicular fluid anti-nucleoprotein total IgG
					Week 1	Week 2	Week 3	Week 4	Positive on first sample	Positive on last sample
A	2	1	0	1	0/1	0/1	0/1	0/1	0/1	0/1
B	3	1	1	1	0/1	0/1	0/1	0/1	0/1	0/1
C‡	6	1	0	5	0/5	0/5	0/4	..	0/5	0/5
D§¶	4	1	0	3	2/3	1/3	1/3	0/3	0/3	1/3
E.1§	4	1	0	3	0/3	0/3	0/3	..	0/3	0/3
E.2‖	4	1	0	3	1/3	..	..	..	0/3	..
E.3§	7	1	0	6	0/6	..	..	..	0/6	..
F	4	2	0	2	1/2	2/2	..	..	0/2	0/2
G.1§	4	1	0	3	0/3	1/3	1/3	0/3	0/3	2/3
G.2§	3	1	0	2	1/2	1/2	1/1	0/1	1/2	2/2
H	3	1	2	0	0/0	0/0	ND	..	0/0	0/0
I	3	1	2	0	0/0	0/0	0/0	..	0/0	0/0
J	4	2	2	0	0/0	0/0	0/0	..	0/0	0/0
K.1§¶	5	1	0	4	1/4	2/4	0/3	0/2	0/4	1/4
K.2	4	2	2	0	0/0	0/0	0/0	0/0	0/0	0/0
M	3	1	0	2	0/2	0/2	0/2	..	0/2	0/2
Total	63	19	9	35	6/35	7/26	3/21	0/11	*1/35	*6/26

Data are n or n/N. A–M and the associated numbers are individual households associated with each educational setting. Where more than one household was associated with a setting, individual households are indicated by an additional number (E.1, E.2, G.1, G.2, K.1, K.2. ..=not done due to intervening holiday or withdrawal from study.

^*Includes index child case: each household had 100% participation rate at time of consent.

^†Includes index child case plus any other child already identified as infected.

^‡Naive household contacts include three children.

^§Naive household contacts include one child.

^¶Household contacts with different genomic sequences to index case are indicated.

^‖Naive household contacts include two children **Proportions are statistically different (p=0·035).)