Page 39 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan

Timeliness of infectious disease reporting, the Netherlands, 2003-2009 37
Background
Accurate communicable disease surveillance systems are essential to initiate and sustain effective public health response and control measures. Efforts to improve completeness and timeliness of surveillance data on infectious diseas- es must therefore be part of a continuous process to improve the quality of surveillance systems in order to minimise further spread of disease [1,2,3].
Timeliness in reporting is crucial in preventing secondary cases and out- breaks of infectious diseases. Delays in the notification process can occur in pa- tients going to their general practitioner or in reporting the laboratory diagnosis to the MHS. According to guidelines, produced by the United States Centers for Disease Control and Prevention, timeliness should be periodically evaluated for each specific surveillance step of each notifiable disease [4]. Nonetheless, a quan- titative measure of timeliness of surveillance systems has not been standardised, and study methods vary, often comparing conventional paper-based systems to electronic systems [5,6] or referring to time limits that differ among countries [7].
Studies with comparable data on surveillance intervals and timeliness are few in number [6-9]. Some surveillance systems did not always record date of symp- tom onset of disease; some analysed time intervals that were omitted by oth- ers, such as the period between hospital admission and notification date [9,10].
The incubation period of a disease, as a proxy for its period of transmissibil- ity, has been used as a quantitative measure to evaluate timeliness of reporting [6,8]. This is justified, as it relates to the time before secondary cases may occur and is also the most effective time for prevention and control measures, such as active or passive immunisation of close contacts or the use of post-exposure prophylaxis [6,11]. In addition, outbreaks are often assumed to have ended af- ter two incubation periods have passed since the end of the period of infec- tiousness of the last case.
In the Netherlands, physicians are legally obliged to report laboratory-con- firmed diagnoses of certain communicable diseases to the local Municipal Health Service (MHS). They should report within one day or within three days if a weekend intervenes. In turn, the MHS reports overnight to the National Institute for Public Health and the Environment (RIVM), using a web-based ap- plication [5].
The introduction of mandatory reporting by laboratories as well as by phy- sicians could potentially improve timeliness [12-15]. During our study period, this hypothesis was investigated by examining physician-laboratory-MHS agree- ments that authorised direct reporting by one or more local laboratories.
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