Table 5.

Two-dose vaccine efficacy stratified by timing of the second dose. Modified total vaccinated cohort in the Costa Rica Vaccine Trial only.

Timing of 2nd doses	Arm	Women, no.	Events, no.	Person years	Rate per 1000 PY (95%CI)	Vaccine Efficacy
Incident one-time detection of HPV16/18
1 month	HPV	300	12	1334	0·90 (0·49 to 1·53)	75·3% (54·2 to 87·5%)
	Control	283	44	1208	3·64 (2·68 to 4·85)
6 months	HPV	97	3	441	0·68 (0·17 to 1·85)	82·6% (42·3 to 96·1%)
	Control	72	12	307	3·91 (2·12 to 6·65)
Incident one-time detection of HPV31/33/45
1 month	HPV	303	36	1304	2·76 (1·96 to 3·78)	10·2% (−42·0 to 43·3%)
	Control	286	38	1236	3·07 (2·21 to 4·18)
6 months	HPV	98	8	431	1·86 (0·86 to 3·53)	68·1% (27·0 to 87·0%)*
	Control	72	17	292	5·82 (3·50 to 9·13)

^*The observed difference in the cross-protective VEs was significantly greater among women who received their second dose at six months compared to one month (p= 0·029).