Influenza vaccination effectiveness for people aged under 65 years in Japan, 2013/2014 season: application of a doubly robust method to a large-scale, real-world dataset

Table 6 Hazard ratios (HR) for onsets of influenza and pneumonia during pre-epidemic periods (2013 Oct 1~ Dec 16) in Japanese subjects: time-dependent Cox hazard model

Outcome definition	Age
	1–4 years		5–12 years		13–19 years		20–64 years
	No. (%) HR (95% CI)	P value	No. (%) HR (95% CI)	P value	No. (%) HR (95% CI)	P value	No. (%) HR (95% CI)	P value
Influenza diagnosis codes only ^a	112 (0.235)	0.991	225 (0.239)	0.806	44 (0.088)	0.665	112 (0.063)	0.281
Influenza diagnosis codes only ^a	1.003 (0.612–1.644)	0.991	0.954 (0.653–1.392)	0.806	0.760 (0.219–2.636)	0.665	1.389 (0.764–2.524)	0.281
ICD10 J101 code + Use of rapid testing ^b	28 (0.059)	0.782	76 (0.081)	0.757	17 (0.034)	0.459	38 (0.021)	0.551
ICD10 J101 code + Use of rapid testing ^b	1.143 (0.443–2.948)	0.782	0.906 (0.485–1.692)	0.757	0.452 (0.055–3.698)	0.459	1.349 (0.505–3.602)	0.551
Pneumonia ^c	1094 (2.293)	0.004	579 (0.615)	0.001	84 (0.168)	0.420	425 (0.239)	0.760
Pneumonia ^c	1.319 (1.091–1.595)	0.004	1.543 (1.182–2.013)	0.001	0.551 (0.129–2.348)	0.420	0.932 (0.594–1.464)	0.760

^aDefined by ICD-10 influenza diagnosis codes (J101, J110, J111, J118)
^bDefined by combination of ICD-10 influenza diagnosis codes (J101: influenza due to identified seasonal influenza virus) with use of a rapid-testing as outcome
^cPneumonia including the ICD-10 codes J12-J18

ISSN: 1471-2334