Timeliness of contact tracing among flight passengers for influenza A/H1N1 2009

BMC Infectious Diseases

Table 1 Overview of 17 contact investigations (n.a.: information on these dates was not available)

Nr	Flight arrival date Schiphol	Dutch (DA)/foreign airline (FA)	Origin	PLCª used	First date of illness	Date of diagnosis	Date request CT	Date contacts identified	Interval I: flight arrival - diagnosis	Interval II: diagnosis - request CT	Interval III: request CT - contact identified	Total Delay (I + II + III)
1	27-4-09	DA	Cancun	No	27-4	29-4	29-4	30-4	2	0	1	3
2	30-4-09	DA	Cancun	No	30-4	6-5	7-5	7-5	6	1*	0	7
3	6-5-09	DA	Mex city	Yes	4-5	7-5	8-5	8-5	1	1	0	2
4	6-5-09	DA	Mex city	Yes	6-5	11-5	12-5	12-5	5	1**	0	6
5	14-5-09	FA	Detroit	No	12-5	n.a.	16-5	16-5	***		0	2
6	21-5-09	DA	NewYork	No	22-5	n.a.	25-5	26-5	***		1	5
7	29-5-09	DA	Houston	No	29-5	n.a.	2-6	2-6	***		0	4
8	29-5-09	DA	Houston	No	n.a.	3-6	4-6	4-6	5	1**	0	6
9	2-6-09	DA	NewYork	No	2-6	3-6	4-6	5-6	1	1	1	3
10	8-6-09	DA	Toronto	No	2-6	n.a.	10-6	11-6	***		1	3
11	13-6-09	DA	NewYork	No	13-6	15-6	16-6	16-6	2	1	0	3
12	18-6-09	DA	Cancun	Yes	13-6	19-6	19-6	20-6	1	0	1	2
13	14-6-09	DA	Miami	No	13-6	16-6	17-6	18-6	2	1	1	4
14	9-6-09	FA	Boston	No	7-6	11-6	12-6	13-6	2	1	1	4
15	14-6-09	DA	Cancun	Yes	11-6	16-6	17-6	17-6	2	1	0	3
16	14-6-09	DA	Cancun	Yes	14-6	17-6	18-6	19-6	3	1	1	5
17	18-6-09	DA	Miami	No	18-6	20-6	20-6	23-6	2	1	2	5
Mean (95%CI)									2,6 (1,6-3,6)	0,8 (0,6-1,1)	0,6 (0,3-0,9)	3,9 (3,2-4,7)

*:. In the beginning of the pandemic one request for contact tracing was accepted after 7 days
**: these late CT requests were accepted as the passenger lists of the concerned flights already were available from earlier contact investigations
***: date of diagnosis not known
ª: Passenger Locator Card

ISSN: 1471-2334