Table 3.

Mean Weekly Numbers of Hospitalizations With Ventilator Use and Rate Ratios (RR) for All Study Years Comparing Non-ITP to PIOP

Individual Hospitalizations	Mean Weekly No. of Hospitalizations Associated With Ventilators			RRa of Increases From Non-ITP to PIOP
Associated With:	During Non-ITP	During PIOP	% Increase From Non-ITP to PIOP	[95% CI]
	(%)	(%)		(P Value)
Ventilators	397 (100)	444 (100)	12	1.07 [1.05-1.10] (<.0001)
Ventilators associated with MAARI	147 (37)	181 (41)	23	1.15 [1.11-1.18] (<.0001)
Ventilators not associated with MAARI	250 (63)	263 (59)	5	1.03 [1.006-1.055] (.01)

Abbreviations: MAARI, medically attended acute respiratory illness; non-ITP, noninfluenza time period; PIOP, peak influenza outbreak period.

^aAdjusted for month and calendar year.