The use of near patient tests in influenza surveillance: Swiss experience and EISS recommendations

Surveillance requires time for analysis and for the communication to physicians. In order to reduce this delay, a new surveillance system based on the use of a near patient test (NPT) has been evaluated. The high specificity of NPT together with the rapidity in obtaining the results, make these tests attractive for surveillance of influenza epidemic in community practice. Such surveillance has been used in several countries including Switzerland. Four different seasons - between 1999 and 2003 - of this type of surveillance experienced in Switzerland have been analysed. The heterogeneity in terms of intensity and type of strains detected during these four epidemics seasons allowed an efficient evaluation. The average gain of time with NPT compared to cell culture was nine days. Furthermore, training of participants appeared to be essential to assure the quality of the surveillance system. A statement on the use of NPTs for influenza surveillance has finally been endorsed by EISS members. Included are recommendations that the network should use the NPTs data, which provides additional information to the classical surveillance systems, as an "early warning" system of a change in influenza activity.