Table 1. Distribution of 2,875 chest radiographs within the batches according to the vaccine period and repeat readings for intra-observer variability evaluation.

Batch No.	Pre-vaccine period images	Post-vaccine period images		Total images	Duplicate images
	n	n	%	N	n	%
1	75	25	25	100	5	5
2	69	31	31	100	5	5
3	75	21	22	96	5	5
4	73	25	26	98	5	5
5	71	25	26	96	5	5
6	75	23	23	98	5	5
7	73	27	27	100	5	5
8	72	25	26	97	5	5
9	62	37	37	99	5	5
10	71	26	27	97	5	5
11	67	29	30	96	5	5
12	71	28	28	99	5	5
13	71	26	27	97	4	4
14	78	20	20	98	5	5
15	73	24	25	97	5	5
16	74	23	24	97	5	5
17	69	29	30	98	5	5
18	75	22	23	97	5	5
19	77	21	21	98	5	5
20	75	25	25	100	5	5
21	68	31	31	99	5	5
22	81	17	17	98	5	5
23	72	28	28	100	6	6
24	70	27	28	97	5	5
25	22	3	12	25	5	20
26	38	47	55	85	5	6
27	30	56	65	86	7	8
28	38	49	56	87	6	7
29	28	49	64	77	6	8
30	29	69	70	98	5	5
31	24	41	63	65	5	8
All	1946	929	32	2,875	159	6