Influenza vaccine effectiveness among healthcare workers in comparison to hospitalized patients: A 2004-2009 case-test, negative-control, prospective study

Figures & data

Table 1. Baseline characteristics of HCW with ILI and patients with or without confirmed influenza, at Edouard Herriot Hospital in Lyon, France, from 2004 to 2009

	HCW with ILI			Hospitalized patients with ILI^b
	HCW with confirmed influenza	HCW without influenza		Patients with confirmed influenza	Patients without influenza
Variables, N (%)	n = 27 (%)	n = 123 (%)	P-value^a	n = 43 (%)	n = 134 (%)	P-value^a
Gender
Male	4 (15)	16 (13)	0.760	8 (19)	50 (37)	0.025
Female	23 (85)	107 (87)		35 (81)	84 (63)
Age (years)
Median (min-max)	42 (22–58)	37 (18–58)	0.800	74 (22–97)	80 (19–101)	0.024
Vaccination	2 (7)	40 (33)	0.008	18 (42)	88 (66)	0.007
Co-morbidities	4 (14.18)	30 (24)	0.324	37 (86)	120 (90)	0.581
Smoking	7 (26)	38 (31)	0.610	5 (12)	13 (10) n = 130	0.776
Influenza season
2004–2005	8 (30)	11 (9)	0.010	12 (28)	34 (25)
2005–2006	2 (7)	35 (28)	5 (12)	51 (38)
2006–2007	10 (37)	27 (22)	18 (42)	17 (13)	<0.001
2007–2008	3 (11)	21 (17)	2 (5)	10 (8)
2008–2009	4 (15)	29 (24)	6 (14)	22 (16)
Ward
Geriatrics	2(7)	32 (26)	0.042	21 (49)	77 (58)	0.379
Other wards	25 (93)	91 (74)	22 (51)	57 (42)
Profession
Medical	2 (7)	23 (19)	0.056	—	—	—
Paramedical	23 (85)	71 (58)	—	—
Administration	2 (7)	19 (15)	—	—
Other	0 (0)	10 (8)	—	—

^a Fisher's exact test or Mann-Whitney test.

^b Amour S, Voirin N, Regis C, Bouscambert-Duchamp M, Comte B, Coppére B, et al. Influenza vaccine effectiveness among adult patients in a University of Lyon hospital (2004-2009). Vaccine 2012; 30(5):821–4.

Table 2. Characteristics of 150 HCW enrolled in ILI and confirmed influenza surveillance at Edouard Herriot Hospital, Lyon, 2004–2009

	November 15 to April 15 (2004–2007)			January 1 to April 15 (2008–2008)
	2004–2005	2005–2006	2006–2007	2007–2008	2008–2009
Variables	n = 19 (%^a)	n = 37 (%^a)	n = 37 (%^a)	n = 24 (%^a)	n = 33 (%^a)	Total n = 150(%^a)
Gender
Male	3 (15.8)	4 (10.8)	6 (15.0)	2 (8.3)	5 (15.2)	20 (13.3)
Women	16 (84.2)	33 (89.2)	31 (83.8)	22 (91.7)	28(84.8)	130 (86.7)
Age (years) median (min-max)	42(23–58)	39 (21–58)	33 (18–52)	35.5 (21–54)	37 (27–58)	38 (18–58)
Vaccinated	8 (42.1)	14 (37.8)	3 (7.5)	7 (29.2)	10 (30.3)	42 (28.0)
Underlying disease	5 (26.3)	11 (29.7)	6 (16.2)	5 (20.8)	7 (21.2)	34 (22.7)
Tobacco use	2 (10.5)	10 (73.0)	18 (48.6)	8 (33.3)	7 (21.2)	45 (30.0)
Number of wards surveyed (n)	13	29	32	7	7	-

^a Unless stated otherwise.

Table 3. Influenza vaccine coverage as percentage of HCW by flu season, Edouard Herriot Hospital, Lyon, France, 2004–2009

	2004–2005	2005–2006	2006–2007	2007–2008	2008–2009	2004 to 2009
Influenza season	n = 19	n = 37	n = 37	n = 24	n = 33	N = 150	P-value^a^b
Number of units (n)	13	29	32	7	7	37	—
Vaccinated individuals, %	42	38	8	29	30	28	—
By ward, %
Geriatrics	86	44	33	50	55	55	<0.001
Other wards	17	36	6	22	21	19
By professional category, %
Medical doctor	50	80	17	67	50	50	0.070
Other HCW	33	39	4	19	23	22
Administrative staff	50	17	25	0	50	32
Others	—	0	0	67	0	20

^a For the 5 seasons (n = 150)

^b Fisher's exact test.

Figure 1. Comparison of vaccine effectiveness (VE) among HCW and patients in 5 influenza seasons, Edouard Herriot Hospital, Lyon, France, 2004–2009. *Adjusted for age, gender and influenza season.