Table 4.

Incidence Rate Ratios of genital warts among girls who initiated vaccination prior to age 15, comparing girls receiving 3 doses with those receiving 2 doses with a >5-month inter-dose interval, IRR (95%CI)

	Base Model (N=33,851*)	Full Model (N=33,851)
2 doses with a 5-month interval	0.91 (0.53, 1.58)	0.97 (0.56, 1.68)
Age** (ref= 9–11)
12	0.43 (0.23, 0.82)	0.50 (0.26, 0.97)
13	0.68 (0.39, 1.20)	0.83 (0.46, 1.48)
14	0.60 (0.34, 1.05)	0.72 (0.41, 1.29)
Region (ref=South)
Northeast		0.74 (0.44, 1.23)
North Central		0.97 (0.65, 1.44)
West		0.68 (0.44, 1.05)
Income (ref= >57,000)
<4,7000		0.65 (0.44, 0.96)
4,7000–5,7000		0.69 (0.48, 1.00)
% of minority population (ref= >35%)
<20%		1.02 (0.67, 1.56)
20%–35%		1.12 (0.75, 1.67)
Year (beginning of exposure period)
2008		0.85 (0.59, 1.24)
2009		0.55 (0.34, 0.91)
2010		0.62 (0.34, 1.13)
2011–2012		0.69 (0.29, 1.67)

^*3 dose group: n=30,527 total girls, 156 cases of genital warts (0.51%); 2 dose group: n=3,154 total girls, 14 genital warts (0.44%)

^**Patient age at start of exposure period. Sample limited to females aged 9–14 at start of exposure periods.