Table 2. Practitioner participation, Influenza-like illness (ILI) patients recruited by case control status, vaccination status, and study site, I-MOVE multi-centre case control study, influenza season 2010-11.

Study site	Number of practitioners in the National sentinel system	Number of practitioners accepting to participate in the study	Number of practitioners recruiting at least one ILI *	Number of ILI patients* recruited by practitioners	Inclusion period for the study†	Number of ILI patients included in the study positive for influenza ‡		Number of ILI patients included in the study negative for influenza ‡
						Total	Vaccinated	Total	Vaccinated
France	571	425	317	1186	wk 51, 2010 –wk 11, 2011	597	15	589	39
Hungary	1400	98	78	727	wk 50, 2010 –wk 13, 2011	119	4	608	52
Ireland	135	48	17	190	wk 48, 2010 –wk 9, 2011	106	0	84	6
Italy	1009+	38	27	415	wk 46, 2010 –wk 13, 2011	116	17	299	64
Poland	971	33	29	180	wk 48, 2010 –wk 14, 2011	98	6	81	10
Portugal	144	58	34	253	wk 45, 2010 –wk 11, 2011	144	6	109	19
Romania	270	89	66	255	wk 52, 2010 –wk 15, 2011	154	7	101	13
Spain	848	246	197	1205	wk 49, 2010 –wk 12, 2011	685	26	520	53
Total	5348	1035	765	4410		2019	81	2391	256

*ILI patients meeting the EU case definition, swabbed < 8 days after onset of symptoms within the study period.

^†For each study site, from 15 days after the start of the vaccination campaign up to the week that preceded two consecutive weeks in which none of the ILI patients recruited tested positive for influenza. Week number as defined by the International Standards Organization to ensure consistency across study sites (ISO weeks used).

^‡ILI patients in the study after applying exclusion criteria (contraindications for vaccine, antiviral use before swabbing, missing lab results) and excluding those not adhering to the EU ILI case definition, having a delay between symptom onset and swabbing of less than 8 days and presenting outside the study period.

⁺Mean number of participating GPs.