Page 142 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan

140 Chapter 6
dates (interval III) were calculated, see Figure 2. Date of actual contact tracing and oseltamivir administration was not available in this study, but is inherently always hours if not days later. As the airline company traces contacts amongst crewmembers, these are not included in this study.
Figure 2. Delay intervals in contact tracing amongst flight passengers. Interval I, II and III are defined as serial intervals between the dates of flight arrival, date of diagnoses, date
of contact tracing request and date of contact details identified respectively
Data were analyzed using SPSS software (version 18, USA). The influence of availability of PLC’s on timeliness and the origin of the airline company (Dutch or non-Dutch) were statistically analyzed.
Results
In the period April 29th until June 22nd 2009, 24 indications for CT were iden- tified. Three international requests concerning CT for influenza patients diag- nosed outside the Netherlands were declined as already more than 4 days had elapsed since flight arrival. In 17 out of the 21 remaining contact investigations, passenger lists with contact details were obtained within 7 days after arrival (81%), see Table 1. In total contact details of 451 close contacts were identified, of which 199 contacts lived in the Netherlands, and 252 contacts abroad. The average number of close contacts per flight was 27 (range: 8–44). In four contact investigations (19%), contact details were not obtained, or provided later than 7 days after flight arrival and CT was stopped. These CT were all related to non- Dutch airlines, and total delay was stated 8 days for further data processing. Of the 21 requests, the total delay between request and contact detail identifica- tion was longer for non-Dutch airlines (mean 6.3 SD 2.7) compared with Dutch airlines (mean 4.1 days, SD 1.5)(1-sided Mann–Whitney test, p = 0.033).