Immunization coverage and risk factors for failure to immunize within the Expanded Programme on Immunization in Kenya after introduction of new Haemophilus influenzae type b and hepatitis b virus antigens

Table 4 The effect of explanatory factors on age-specific immunization rates with pentavalent vaccine among children in the simple random survey aged 9–23 months in Kilifi District, Kenya

Variable	Univariate immunization rate ratio (95% CI)		Adjusted Immunization rate ratio (95 % CI)
rainy season*	0.73	(0.61–0.89)	0.73	(0.61–0.89)
recent rainfall >3 mm/day^†‡	0.94	(0.88–1.00)	-
distance to vaccine clinic (per 1 km)	0.94	(0.89–0.98)	0.95	(0.91–1.00)
mother's age = 20 years^‡	0.56	(0.40–0.80)	-
one child in the family	1		1
two children in the family	0.71	(0.51–0.97)	0.74	(0.53–1.04)
three children in the family	0.62	(0.45–0.87)	0.61	(0.43–0.87)
four or more children in the family	0.53	(0.41–0.70)	0.55	(0.41–0.73)

* Survival time, the 28 days before the vaccine due date, began during a rainy season month defined as a mean daily rainfall ≥ 3 mm throughout the years 1992–2004.
^† mean rainfall in the 14 days before the vaccine was due
‡ These variables were excluded from the multivariable model because a Likelihood Ratio Test of their contribution to the model yielded p > 0.05

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