Table 4—

Data on spirometric parameters

	All weeks of illness			Influenza-positive weeks
	Vaccine	Placebo	p-value	Vaccine	Placebo	p-value
Outcomes n	172	157		21	20
FEV₁	1.95±0.75	2.00±0.86	0.63	1.77±0.82	1.59±0.67	0.31
% predicted	87±17	85±17	0.24	89±22	80±20	0.09
FVC	2.25±0.85	2.31±1.02	0.60	2.06±0.52	1.92±0.82	0.53
% predicted	87±16	85±17	0.14	91±18	80±19	0.08
MEF₅₀	2.36±1.0	2.38±1.0	0.87	2.08±0.50	1.83±1.0	0.32
% predicted	81±25	79±24	0.69	78±17	75±29	0.66
MEF₂₅	1.29±0.64	1.33±0.71	0.56	1.11±0.28	0.98±0.56	0.35
% predicted	88±36	88±35	0.86	83±21	82±33	0.92
Differences^# n	162	153		21	20
FEV₁	−7±13	−8±12	0.31	−4±12	−12±11	0.06
FVC	−5±14	−6±14	0.34	−0±12	−11±15	0.01
MEF₅₀	−10±16	−11±20	0.59	−11±15	−17±15	0.17
MEF₂₅	−8±29	−10±30	0.37	−13±22	−13±19	0.88

Data are presented as mean±sd. FEV₁: forced expiratory volume in one second; FVC: forced vital capacity; MEF₅₀: maximum expiratory flow (MIF) at 50% of FVC; MEF₂₅: MIF at 25% of FVC. ^#: differences in % predicted comparing spirometry at baseline and during illness weeks