Estimating severity of influenza epidemics from severe acute respiratory infections (SARI) in intensive care units

Table 1 Number of ICUs in the NICE registration and medical and SARI admissions per season (2007–2016)

Season	Mean number of ICUs^a	Medical ICU admissions ^b			SARI admissions
Season	Mean number of ICUs^a	Weekly mean (SD)	Weekly minimum and maximum	Total	Weekly mean (SD)	Weekly minimum and maximum	Total (percentage^c)	Weekly minimum and maximum (percentage^c)	Standardized SARI incidence^d	SARI rate^e
2007–2016	70	503 (145)	161–784	236,282	65 (28)	11–176	30,515 (13%)	5–25%
2007/2008	39	239 (44)	161–316	12,411	32 (10)	11–55	1657 (13%)	6–18%	4596	3.27
2008/2009	54	343 (64)	228–494	17,851	46 (19)	14–99	2369 (13%)	5–22%	4568	3.25
2009/2010	68	434 (38)	311–502	23,023	56 (15)	25–87	2947 (13%)	7–19%	4406	3.13
2010/2011	73	485 (46)	364–601	25,222	66 (19)	33–119	3452 (14%)	7–21%	4711	3.35
2011/2012	75	523 (52)	417–658	27,188	66 (18)	36–105	3447 (13%)	8–18%	4364	3.10
2012/2013	77	574 (63)	447–735	29,862	78 (29)	35–163	4060 (14%)	8–25%	4680	3.33
2013/2014	77	608 (46)	515–733	31,620	68 (16)	39–97	3539 (11%)	7–15%	3853	2.74
2014/2015	81	667 (56)	537–784	34,682	88 (30)	46–154	4561 (13%)	8–20%	4527	3.22
2015/2016	81	649 (55)	555–744	34,423	85 (36)	39–176	4483 (13%)	6–24%	4483	3.19

NICE National Intensive Care Evaluation, SARI Severe acute respiratory infections
^aNumber of participating ICUs were calculated per calendar year (starting from 1 January)
^bExcluding ICU admissions for surgery or trauma
^cPercentage of total medical ICU admissions
^dSARI admissions standardized to the total number of medical ICU admissions in season 2015/2016 (with near 100% national ICU coverage)
^eRate was calculated with total 15+ Dutch population size in 2015 (at a scale of 1/10,000)

ISSN: 1364-8535