. 2015 Oct 14;108(1):djv302. doi: 10.1093/jnci/djv302

Table 5.

HPV16/18 vaccine efficacy among individuals with cervical HPV16 or HPV18 DNA detected at enrollment

Study population	Arm	Women or sites	No. events	HPV prevalence, %	Efficacy (95% CI), %
Anal or oral HPV16/18 at the four-year visit	HPV vaccine	192	16	8.3	25.3 (-40.4 to 61.1)
Anal or oral HPV16/18 at the four-year visit	Control	215	24^*	11.2	25.3 (-40.4 to 61.1)
Redetection of cervical HPV16/18 (among women with HPV16/18 at enrollment who subsequently cleared their infection)†	HPV vaccine	180	10	5.6	38.9 (-31.7 to 72.9)
	Control	198	18	9.1	38.9 (-31.7 to 72.9)
HPV16/18 at two or three sites at the four-year visit	HPV vaccine	192	3	1.6	44.0 (-124.9 to 88.6)
HPV16/18 at two or three sites at the four-year visit	Control	215	6	2.8	44.0 (-124.9 to 88.6)

* Only two of the 40 total anal/oral events were oral HPV16/18 infections. These two oral HPV16/18 infections were both detected in the control arm, but oral HPV16/18-specific vaccine efficacy did not approach statistical significance given its small sample size. CI = confidence interval; HPV = human papillomavirus. † Clearance defined as one negative cervical HPV16/18 DNA test after the positive cervical HPV16/18 DNA test.