Table 1 Thirteen strategies to improve influenza surveillance

(1) Increase the number/density of traditional reporting sources

   Increasing the number of traditional reporting sources, e.g., doctors, clinics, hospitals, would increase the percentage of the population covered through surveillance.

(2) Develop community-based alert and response systems

   Community-based surveillance systems would help increase coverage by capturing information on illnesses within the community that may not otherwise reach government attention.

(3) Incorporate new human disease sources and signals

   Gaps in surveillance coverage could potentially be addressed through reporting from new sources (e.g., workplaces, schools, local media, web logs) and new signals (e.g., work or school absenteeism, rumors of compatible cases or outbreaks, or local reports of surge in hospital demand).

(4) Increase reporting compliance

   Assuring the regular voluntary reporting of cases by various surveillance sources (doctors, hospitals, communities, businesses, etc.) assures that the surveillance system in place captures information from all designated reporting sites, thereby improving coverage.

(5) Improve human laboratory sample preparation and diagnostic capacity

   Laboratory diagnosis confirms the occurrence of influenza disease and is an important element of surveillance quality; this strategy involves the development and deployment of standard laboratory protocols, training, and regular proficiency testing.

(6) Implement targeted laboratory testing appropriate to the pandemic phase and location

   Potentially scarce laboratory resources can better assure quality services when they are not overwhelmed by demand; criteria for targeted testing, e.g., clinically compatible cases with specified epidemiologic risk factors, should be widely disseminated to and applied by clinical providers.

(7) Improve epidemiologic capacity

   Training in surveillance and applied epidemiology will help improve surveillance quality, including analysis and interpretation of surveillance data and investigation of suspicious cases.

(8) Use data mining methods for early warning

   Capitalizing on data mining methods, such as the Global Public Health Intelligence Network (GPHIN), which employs data mining techniques to systematically scour the electronic news media in multiple languages worldwide for reports of disease occurrences and then process to help discern "signal" from "noise" (14), can improve the timeliness of influenza surveillance.

(9) Expand expedited transport of specimens to in-country and international reference laboratories

   Efforts must be scaled up to assure that specimens anywhere in the world can reach an international laboratory in timely fashion; rapid transport of laboratory specimens from their point of origin (the sick individual) to the first and any subsequent in-country laboratories is also critical.

(10) Streamline notification, analysis and reporting

   Transmission of surveillance data between sub-national and national levels should employ the efficient modalities and channels; reporting electronically or even by telephone should be the desired global norm for surveillance of diseases for which timeliness is a particular priority, including human cases of avian influenza, and electronic technologies should be harnessed for streamlined data processing and analysis.

(11) Implement active surveillance when appropriate

   While active surveillance, in which government authorities directly solicit information about disease occurrence from potential sources such as hospitals and clinical providers, is more labor intensive than routine approaches in which such providers submit reports at regular intervals, selective use of active surveillance can be critical to enhance timeliness of case detection.

(12) Develop and deploy rapid laboratory diagnostics with greater sensitivity and reproducibility

   The development and widespread deployment of more accurate rapid diagnostic tests, including tests that could identify influenza virus subtype, could improve the timeliness of influenza surveillance.

(13) Develop and deploy in-country and international Rapid Response Teams to investigate cases/outbreaks

   The development and deployment of in-country and international Rapid Response Teams can improve the timeliness of surveillance by triggering rapid investigation and subsequent control measures.