The role of facemasks and hand hygiene in the prevention of influenza transmission in households: results from a cluster randomised trial; Berlin, Germany, 2009-2011

Table 3 Separate models for predictors of qRT-PCR confirmed influenza infection and clinical influenza among included households.

Variable	RT-PCR confirmed Influenza			ILI
	OR	95% CI	p-value	OR	95% CI	p-value
Intervention Group
Control Group	Ref.			Ref.
Mask Group	0.39	0.13-1.19	0.10	0.56	0.18-1.68	0.3
Mask & Hygiene Group	0.61	0.23-1.66	0.34	0.47	0.15-1.49	0.2
Intervention Groups combined
Control Group	Ref.			Ref.
Mask Group + Mask & Hygiene Group	0.50	0.21-1.20	0.12	0.51	0.2-1.28	0.15
Sex*
Female	Ref.			Ref.
Male	1.2	0.62-2.28	0.52	0.65	0.3-1.42	0.28
Age*
Adult (> 14 yrs)	Ref.			Ref.
Child	1.52	0.71-3.23	0.28	2.22	0.97-5.08	0.06
Time spent at home*
< 18 hours/day	Ref.			Ref.
≥18 hours/day	3.1	1.3-7.33	0.01	3.98	1.34-11.77	0.01
Therapy of Index patient*
No timely therapy	Ref.			Ref.
Timely therapy	1.63	0.70-3.81	0.26	1.07	0.42-2.7	0.89
Vaccination of Contact*
No vaccination	Ref.			Ref.
Vaccination	0.62	0.11-3.56	0.6	0.48	0.06-3.94	0.49

Independent variables: (i) intervention group, (ii) intervention group (with pooled data of Mask- and Mask&Hygiene group), (iii) one separate model for each individual variable that may influence household transmission of influenza (i.e. age, sex, timely antiviral therapy of the index, vaccination of household contacts) adjusted for intervention group
OR Odds ratio, 95% CI 95% Confidence Interval
*Models also included intervention group as independent variable

ISSN: 1471-2334