Page 147 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan
P. 147

Timeliness of contact tracing among flight passengers 145
of the disease decreased significant during this study period [22]. We expect that the delay until laboratory diagnoses in this study considerably is affected by patients delay seeking medical care, which might be better in diseases expe- rienced as more threatening.
Collecting passenger details from foreign airlines also caused considerable delay because of differences in time zones and the need to convince the con- cerned airline companies about the urgency to collect and hand-over passenger lists with contact details. Sometimes official request letters were necessary for legal reasons to release personal contact details. Dutch companies were easier to convince by Dutch health authorities to hand over passenger details. Our data show that contact details that were identified too late or not at all, indeed more often originated from non-Dutch than from Dutch airline companies. An internationally standardized contact tracing protocol, communicated with the International Civil Aviation Organization (ICAO) and International Air Transport Association (IATA), would facilitate the timeliness, and therefore effectiveness of contact tracing.
Although one might expect differently, timeliness of CT for flights where PLC’s were available, was not better than CT for flights without PLC. However, PLC’s reduces the effort, in terms of staff support for airline companies and the municipal health service to collect useful passenger information considerably. PLC’s were only used by Dutch airlines, who already were able to provide pas- senger lists relatively quickly. This also explains the limited attributed shorte- ning in timeliness. Contact details on PLC’s might be more accurate to trace the passenger than details provided by the passenger list or booking station. This is further investigated.
This study has several limitations. As available data were recorded in days, and not in hours, it was not possible to determine the time intervals more pre- cisely. As this was both with first and last date of the intervals, we expect no negative or positive bias. Secondly, the arrival date was used for date of exposu- re, while the actual exposure might have already taken place the day before at departure of the flight. This would imply an increase in delay and decrease the effectiveness of contact tracing. Also, we have no data if, and when contacts were actually reached and oseltamivir was administered. Since several steps were still required to reach the contacts after they were identified through pas- senger lists, this only would have lead to further delay in administrating prophy- laxis. Further investigation into the timeliness of administration of prophylaxis among these contacts is initiated, to have insight in the delay of this last interval to facilitate future decisions on the effectiveness and necessity of contact tra-
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