Table 1. Basic data used in the test-negative case-control study and the case-series study.

	Data from national reference and state laboratories (test-negative case-control method)					Data from reporting system (case-series method)
Variable	With information		among those with information
	N	%		N	%	N	%
Lab result for pIV	6195	100%	positive	2837	46%	NA	NA
			negative	3358	54%	NA	NA
Vaccination against pandemic A/(H1N1) 2009	3836	62%	Vaccinated more than 14 days before illness onset	42	1%	57	0.1%
			Not vaccinated or not in time	3794	99%	73229	99.9%
Vaccination against seasonal influenza	5180	90%	Vaccinated more than 14 days before illness onset	491	9%	NA	NA
			Not vaccinated or not in time	4689	91%	NA	NA
Age	6156	99%	0–9	2452	40%	18877	26%
			10–19	1797	29%	28634	39%
			20–29	568	9%	8173	11%
			30–39	437	7%	5671	8%
			40–49	459	7%	6963	10%
			50–59	300	5%	3715	5%
			60–69	77	1%	853	1.2%
			70+	66	1%	393	0.5%
Sex	6124	99%	Male	3173	52%	36628	50%
			Female	2951	48%	36387	50%
Underlying disease	2653	43%	Respiratory	237	9%	NA	NA
			Cardiovascular	75	3%	NA	NA
			Diabetes	28	1%	NA	NA
			unspecified	141	5%	NA	NA
			none	2172	82%	NA	NA

Completeness and frequency distribution of variables describing (a) the study population of patients whose sample was sent to the National Reference Center for Influenza or to one of four state laboratories and tested for pandemic influenza virus A/(H1N1) 2009 (test-negative case-control method); and (b) characteristics of the patients reported to the public health system (used in the case-series method); Germany, 2009/10.