Page 75 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan

Timeliness of notification systems: a systematic literature review 73
It is remarkable that studies provide little background explanation about the designated timeframes, except when incubation periods are used, which are considered to be related to communicability and therefore critical when consid- ering control measures [3, 46], or when timeframes related to measures such as post exposure prophylaxis are used [37]. The purpose of notification systems in general is an early warning system to identify outbreaks, to enable public health authorities to take corrective action through effective preventative and/ or control measures, and to monitor the effect of implemented measures [48]. Timely notification for this purpose is disease specific, as we have demonstrat- ed earlier [4]. Using available data on notification delays in the Netherlands for six person-to-person communicable diseases, at the time of reporting to local public health services, over 80% of secondary cases already were infected by the index. Therefore timely notification will mainly prevent tertiary, and fur- ther, cases. In none of the eight studies in this review that provided relevant information regarding D1 medians for these six diseases, the notification system was timely for effective outbreak control. This might be one of the reasons why infectious diseases such as measles are difficult to control and still are endemic in many industrialized countries.
Another aspect is that only certain parts of the notification chain can be influenced through the notification system: mainly the reporting of a confirmed infectious disease from laboratory and/or physician to the local health depart- ment (D3), and from here to regional and/or national level (D4-D5). Timeliness outcomes for these delays were less sufficient than for D1-D2 in the standard- ized system. This review shows that many notification systems therefore can be improved to minimize delays D3 and D4-5. However, patient delay to consult a physician is not related to a notification system, neither the doctor’s delay in recognizing a disease. As patient, doctor’s and laboratory delays (D1,D2) take longer time than notification delays D3, D4, D5, (S 1 Table) optimizing notifica- tion systems will only partly optimize the timeliness of the entire notifications chain. Reduction of patient, doctor’s and laboratory delays, through increased awareness and enhanced availability of laboratory tests, is essential to substan- tially improve timeliness of the notification chain. This is certainly indicated in situations of increased threats. In such situations, also temporary conventional notification methods as telephone calls to the local health departments have an added value. Therefore decisions on investments in notifications systems should take into consideration the reduction in timeliness in D3, D4-D5 com- pared to potential reduction of D1-D2 and D3 (telephone) in case of specific health threats.
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