Validity and timeliness of syndromic influenza surveillance during the autumn/winter wave of A (H1N1) influenza 2009: results of emergency medical dispatch, ambulance and emergency department data from three European regions

Table 2 Properties of the reference data

				Influenza pandemic according to reference data in 2009
Reference data for…	Reference data source	Geographical level	Reporting delay*	Start week	Peak week	Duration (weeks)	Duration (days)
EMD-AT^†, EP-AT^†	Information on sick leave due to acute respiratory infections from a major Tyrolean health insurance.	regional	information for week x available on week x + 1	44	47	9	67^$
EMD-AT^†, EP-AT^†		(Tyrol, Austria)	information for week x available on week x + 1	44	47	9	67^$
EP-BE,	Notified influenza cases of the sentinel general practitioner system.	national	information for week x available on week x + 3	40	44	10	70
ED-BE		(Belgium)	information for week x available on week x + 3	40	44	10	70
ED-ES	Notified influenza cases of the sentinel general practitioner system.	regional	information for week x available on week x + 3	41 (period 1)	43	8	56
		(Autonomous Region Cantabria, Spain)		49 (period 2)

*week: Monday (day 1), …, Sunday (day 7).
^†The course of the autumn/winter wave was derived from regional data of the Tyrolean health insurance; the start week of the autumn/winter wave was derived from national data [27].
^$last week of 2009 (week 52) contained 11 days.

ISSN: 1471-2458