( ( ( ( ( ( HPV ( vaccines ( ( Gardasil and ) Cervarix ) ) ) , ) ( which ( ( block ( initial infection ) ) ( with ( some ( of ( ( the ( most common ) ) ( sexually ( transmitted ( HPV types ) ) ) ) ) ) ) ) ) ) , ) ( may ( ( ( lead ( to ( ( further decreases ) ( in ( ( the incidence ) ( of ( HPV-induced cancer ) ) ) ) ) ) ) , ) however ) ) ) ( , ( they ( ( ( do not ) ( address ( ( the millions ) ( of ( people ( worldwide ( already ( infected ( with ( the virus ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (NP (NNP HPV) (NNP vaccines) (NNP Gardasil) (CC and) (NNP Cervarix)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VB block) (NP (JJ initial) (NN infection)) (PP (IN with) (NP (NP (DT some)) (PP (IN of) (NP (NP (DT the) (RBS most) (JJ common)) (VP (ADVP (RB sexually)) (VBN transmitted) (NP (NNP HPV) (NNS types)))))))))) (, ,)) (VP (MD may) (VP (VB lead) (PP (TO to) (NP (NP (JJ further) (NNS decreases)) (PP (IN in) (NP (NP (DT the) (NN incidence)) (PP (IN of) (NP (JJ HPV-induced) (NN cancer))))))) (, ,) (ADVP (RB however))))) (, ,) (NP (PRP they)) (VP (VBP do) (RB not) (VP (VB address) (NP (NP (DT the) (NNS millions)) (PP (IN of) (NP (NP (NNS people)) (VP (ADVP (RB worldwide)) (ADVP (RB already)) (VBN infected) (PP (IN with) (NP (DT the) (NN virus))))))))) (. .)))
HPV vaccines Gardasil and Cervarix, which block initial infection with some of the most common sexually transmitted HPV types, may lead to further decreases in the incidence of HPV-induced cancer, however, they do not address the millions of people worldwide already infected with the virus.
(ROOT (S (NP (NNP Gardasil)) (VP (VBZ is) (NP (DT the) (NN vaccine) (S (VP (TO to) (VP (VB prevent) (NP (NP (NN infection)) (PP (IN of) (NP (NN hpv))))))))) (. .)))