Gender-specific mortality in DTP-IPV- and MMR ± MenC-eligible age groups to determine possible sex-differential effects of vaccination: an observational study

Table 5 Incidence rate ratios (IRR) for girls compared with boys for indigenous Dutch children only, for the periods before and from September 2002 onwards, and for natural causes of death other than complications of pregnancy, childbirth, perinatal period and congenital abnormalities

Age group	IRR^a	p-value	IRR^a	p-value	IRR^a	p-value	IRR^a	p-value	IRR^a	p-value
Age group	(95% CI) for natural causes for indigenous Dutch children only(N_deaths = 9,328)	p-value	(95% CI) for natural causes before September 2002(N_deaths = 3,529)	p-value	(95% CI) for natural causes from September 2002 onwards(N_deaths = 9,221)	p-value	(95% CI) for natural causes other than complications of pregnancy, childbirth, perinatal period and congenital abnormalities(N_deaths = 4,029)	p-value	(95% CI) for infectious and parasitic diseases(N_deaths = 374)	p-value
0-1 months	0.80 (0.76-0.84)		0.81 (0.74-0.88)		0.82 (0.78-0.86)		0.97 (0.82-1.15)		1.13 (0.67-1.90)
2-13 months	0.78 (0.70-0.87)		0.86 (0.73-1.02)		0.79 (0.71-0.88)		0.74 (0.65-0.84)		0.79 (0.55-1.13)
14 months – 3 years	0.79 (0.69-0.90)	0.882^b	0.81 (0.66-0.99)	0.637^b	0.87 (0.76-0.99)	0.266^b	0.82 (0.73-0.93)	0.789^b	0.90 (0.63-1.27)	0.621^b
4-8 years	0.83 (0.72-0.96)	0.637^c	0.75 (0.59-0.96)	0.652^c	0.87 (0.75-1.01)	0.973^c	0.85 (0.74-0.97)	0.217^c	0.95 (0.52-1.75)	0.863^c
9-11 years	0.92 (0.75-1.11)		0.72 (0.52-0.98)		1.00 (0.82-1.21)		0.89 (0.75-1.06)		0.71 (0.33-1.54)
		0.673^d		0.835^d		0.248^d		0.112^d		0.817^d

^aAdjusted for calendar year.
^bp-value for interaction (df = 1) between age group and gender for 14 months – 3 years of age versus 2–14 months of age.
^cp-value for interaction (df = 1) between age group and gender for 4–8 years of age versus 14 months – 3 years of age.
^dp-value for interaction (df = 4) between age group and gender for all age groups.

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