We also noted significant cross-protective vaccine efficacy against @-month persistent infection with HPV @ ( @ % , @ % CI @-@ ) and HPV @ ( @ % , @-@ -RSB- ) Serious adverse events occurred in @ ( @ % ) of @ women in the vaccine group and @ ( @ % ) of @ in the control group ; five ( < @ % ) and eight ( < @ % ) of these events , respectively , were believed to be related to vaccination .